ORIGINAL RESEARCH
Correlation Between Nutritional Markers and Appetite Self-Assessments in Hemodialysis Patients Claudia M. C. Oliveira, PhD, Marcos Kubrusly, PhD, Andre. T. Lima, Danielle M. Torres, Natasha M. R. Cavalcante, Ant^onio L. C. Jer^onimo, MD, and Thiago. C. B. Oliveira Objective: Protein–energy malnutrition is among the comorbidities that most strongly affect the prognosis of patients with chronic kidney disease. Anorexia, defined as a loss of desire to eat, is one cause of such malnutrition. Tools that evaluate appetite and the correlation between appetite and nutritional parameters require further study. To evaluate the appetite status in patients from 2 hemodialysis clinics in Fortaleza, Brazil and the correlations between appetite (evaluated in the past week and in the past 4 weeks) and demographic, laboratory, and nutritional parameters. Methods: This was a cross-sectional study of patients aged $18 years who had undergone dialysis for .3 months. Appetite was evaluated using the first 3 questions of the Appetite and Diet Assessment Tool (ADAT) questionnaire, which evaluate the appetite status during the past week as well as 1 question from the Kidney Disease and Quality of LifeÔ Short Form that assesses appetite in the past 4 weeks. The patients were divided into 3 groups according to the degree of appetite: group 1: very good and good appetite (ADAT) or not and somewhat (Kidney Disease and Quality of LifeÔ Short Form); group 2: fair or moderately; and group 3: poor and very poor, or very much and extremely. The nutritional parameters evaluated were body mass index (BMI), serum albumin, Geriatric Nutritional Risk Index (GNRI) and lean body mass index (lean mass in kilogram per square meter) as obtained by multifrequency bioelectrical impedance analysis. Patients with a BMI ,23 kg/m2, albumin ,4 g/dL, GNRI ,98, and lean body mass index below the lowest quartile were considered malnourished. The associations between appetite and nutritional variables were tested using Fisher exact test and by comparing the means of the variables in the 3 groups using the analysis of variance and Kruskal–Wallis tests. Results: A total of 136 patients were included in the study with a mean age of 50.9 years and a median time on dialysis of 45 months; 57% of the patients were male. Regarding the first question on the ADAT questionnaire, 36% of patients exhibited anorexia in the past week. Furthermore, 28.7% of the population reported a lack of appetite in the last month. Moreover, 34.3% of the patients were considered malnourished according to BMI, 34.1% according to albumin, and 31.6% according to GNRI. Among the studied variables, the mean values of the following variables were different between groups 1, 2, and 3: hemoglobin (P 5 .0186), creatinine (P 5 .0392), albumin (P 5 .0065), GNRI (P 5 .0274), and lean BMI (P 5 .0274). Conclusions: The prevalence of a lack of appetite in hemodialysis patients in both the past week and the past month was high in the present study. The questionnaire evaluating appetite in the last 4 weeks could be used as a malnutrition screening tool in hemodialysis patients as suggested by the correlation of decreased appetite in the last month with variables that assess nutritional status such as albumin, lean body mass index, and GNRI. Ó 2015 by the National Kidney Foundation, Inc. All rights reserved.
P
Introduction
ROTEIN–ENERGY MALNUTRITION (PEM) is among the factors that most strongly affect the prognosis of patients with chronic kidney disease and is associated with increased morbidity and mortality even in the presence of adequate dialysis and protein intake.1-3 Studies have demonstrated evidence of malnutrition in 23% to 76% of hemodialysis patients and in 18% to 50% of patients undergoing peritoneal dialysis.4-6 The etiology of PEM is multifactorial and could be related to a concomitant Nephrology Department of Unichristus University, Fortaleza-Ceara, Brazil. Financial Disclosure: The authors declare that they have no relevant financial interests. Address correspondence to Claudia M.C. Oliveira, PhD, Centro Universitario de Medicina Christus, UniChristus, Universidade Federal do Ceara, Professor Jacinto Botelho Street 500, Fortaleza 60810-050, Ceara, Brazil. E-mail:
[email protected] Ó
2015 by the National Kidney Foundation, Inc. All rights reserved. 1051-2276/$36.00 http://dx.doi.org/10.1053/j.jrn.2014.09.006
Journal of Renal Nutrition, Vol -, No - (-), 2014: pp 1-7
inflammatory process, nutrient loss during dialysis, uremic endocrine disorders, low food intake, and anorexia.7 Anorexia is defined as the loss of desire to eat and is commonly observed in patients undergoing hemodialysis; this eating disorder contributes to the development of malnutrition and cachexia, poor quality of life, mortality, and hospitalization.8-10 Nutritional status assessment of dialysis patients and early detection of the causes of malnutrition are crucial to its prevention. There is no gold standard to evaluate the nutritional status of hemodialysis patients; however, in clinical practice, some methods have been suggested for this purpose such as the body mass index (BMI), serum albumin level, lean body mass (LBM), Geriatric Nutritional Risk Index (GNRI), and appetite assessment questionnaires.11,12 Appetite can easily be self-assessed by the patient through answering questions from different questionnaires such as the appetite and diet assessment tool (ADAT),13,14 Subjective Global Assessment (SGA)15 and the Kidney Disease Quality of Life Short Form (KDQOL-SF).16 The 1
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ADAT was developed by the National Institutes of Health to evaluate appetite and the factors that affect food intake in hemodialysis patients in the past week; the first 3 questions address appetite.14 A question from the KDQOLSFÔ addresses appetite during the past 4 weeks. This single question regarding a lack of appetite has been associated with a worse nutritional status, inflammation, depression, and increased risks of hospitalization and death.11 Studies evaluating the prevalence of lack of appetite in hemodialysis patients and the relevance of questionnaires for anorexia diagnosis are scarce. An association between decreased appetite and some nutritional markers as BMI, creatinine, and albumin has been previously demonstrated, but more recent parameters such as GNRI and LBM assessed by bioelectrical impedance have not been studied. The present study aims to estimate the prevalence of anorexia in hemodialysis patients in 2 clinics in Fortaleza, Brazil according to 2 different questions and to evaluate the correlations between appetite and nutritional parameters.
Methods The study was conducted between July 2011 and July 2012. Patients aged $18 years who had undergone dialysis for .3 months were included in the study. The ability to respond to questionnaires and undergo anthropometric measurements in addition to providing signed informed consent forms was required. Pregnant women, patients with amputated limbs and paraplegics, in whom the application of bioelectrical impedance was not viable, were excluded. Appetite was evaluated using the first 3 questions of the ADAT questionnaire,14 which evaluate the appetite status during the last week (very good, good, fair, poor, or very poor) and whether there was a change in appetite in the last week (increased or decreased). An additional question from the KDQOL-SFÔ (version 1.3) was given to patients to evaluate their appetite during the past month (not at all bothered, somewhat bothered, moderately bothered, very much bothered, or extremely bothered).16 The responses ‘‘fair, poor, and very poor’’ on the ADAT and the responses ‘‘moderately bothered, very much bothered, and extremely bothered’’ on the KDQOL-SFÔ were defined as a lack of appetite (anorexia). For the statistical analysis, the patients were categorized into 3 groups according to their 5 possible answers to the 2 questions: group 1 (very good or good on ADAT/not at all bothered or somewhat bothered on the KDQOL-SFÔ); group 2 (fair on ADAT/moderately bothered on KDQOL-SFÔ); and group 3 (poor or very poor on ADAT/moderately to extremely bothered on KDQOL-SFÔ). The nutritional status of the patients was evaluated according to their BMI, serum albumin, GNRI, and LBM. The patients’ weights and heights were obtained after a dialysis session, and the BMI (kilogram per square meter) values
were subsequently calculated. Patients with a BMI ,23 kg/ m217 were considered malnourished. The albumin levels were measured during the predialysis period according to the bromocresol green method.18 Albumin levels ,4 g/dL were considered to indicate malnutrition.17 GNRI was calculated using the following equation: GNRI 5 [1.489 3 albumin (g/L)] 1 [41.7 3 weight/ideal weight].19,20 Ideal body weight was calculated according to the patient’s height and the ideal BMI of 22 kg/m2. The nutritional status was classified according to the following: GNRI ,82, severe malnutrition; GNRI 82 to 92, moderate malnutrition; GNRI 92 to 98, low risk; and GNRI .98, no risk. LBM was estimated via multifrequency bioelectrical impedance with a Body Composition Monitor device (Fresenius Medical Care, Bad Homburg vor der H€ ohe, Germany).21 Bioelectrical impedance was performed before initiating the dialysis session. Disposable electrodes were placed on the dorsal aspect of the wrist and on the third finger contralateral to the vascular access as well as on the anterior aspect of the ankle and on the third ipsilateral toe. The Body Composition Monitor report card data were transferred to the Dialysis Clinic’s microcomputer, which calculated lean and fat body masses. The index of lean body mass (LBMI) was calculated by dividing LBM by height squared. Patients with an LBMI below the lowest quartile were considered malnourished.17 The evaluated demographic data included age, gender, and time on dialysis. The variables related to dialysis treatment included the frequency and duration of treatment, type of vascular access, and adequacy of dialysis as estimated by Kt/V. Kt/V was obtained via 2-point urea kinetics modeling.22 Other evaluated laboratory variables included hemoglobin, urea, creatinine, potassium, and phosphorus.
Statistical Analysis The SPSS 20.0 (IBM Corp, Armonk, NY) software was used for the statistical analysis. Continuous variables are expressed as means 6 standard deviations, and the categorical variables are expressed as a frequency or a percentage. The association between the nutritional variables and the degree of appetite was assessed by comparing the mean values of the variables in the 3 groups using one-way analysis of variance followed by Bonferroni test. A P value , .05 was considered significant.
Results A total of 136 patients were included in this study, of whom 57% were male; the mean age was 50.9 years, and the median time on dialysis was 45 months. The demographic characteristics, dialysis treatment, and laboratory data of the study population are shown in Table 1. According to the ADAT, the appetite in the past week was very good in 11.8% of patients, good in 52.2%, fair
NUTRITIONAL MARKERS AND APPETITE IN DIALYSIS Table 1. Demographic, Dialysis Treatment, and Laboratory Characteristics of the Studied Patients Variable Age Gender Time on dialysis (mo) Duration of dialysis (h) Dry weight (kg) Height (m) Hemoglobin Urea Creatinine Potassium Phosphorus Kt/V
Mean
Std. Dev.
50.9 Male: 57% 69 4.0 57.5 1.60 12.2 123 9.9 5.0 5.0 1.60
15.6 Female: 43% 59 0.2 12.2 0.08 1.7 30 2.8 0.7 15 0.42
in 27.2%, poor in 5.1%, and very poor in 3.7%. Furthermore, 22% of the patients reported a change in appetite in the past week (n 5 30); the appetite increased in 13 patients (43.3%) and decreased in 17 patients (56.7%). According to the KDQOL-SFÔ question regarding the past month, 18.4% of patients reported being not at all bothered by a lack of appetite, 52.9% were somewhat bothered, 19.9% were moderately bothered, 5.9% were very much bothered, and 2.9% were extremely bothered. In summary, the prevalence of decreased appetite was 36% in the past week according to ADAT question 1 and 28.7% in the past 4 weeks according to KDQOL-SFÔ question. There was no significant difference between the prevalence of lack of appetite on days with (36%) and without dialysis (38.2%). The nutritional status variables are listed in Table 2. The results showed that 34.3% of the patients were considered malnourished according to the BMI, 34.1% according to albumin levels, 31.6% according to GNRI, and 24.6% according to the LBMI. There were no significant differences between the degree of appetite in the past week (groups 1, 2, and 3) with respect to the study variables (Table 3). A time on dialysis $60 months was observed in 50.5%, 27%, and 25% of patients in groups 1, 2, and 3, respectively (P 5.024). When assessing the degree of appetite in the past 4 weeks, the results showed significant differences between groups 1, 2, and 3 for mean values of the following variables: hemoTable 2. Nutritional Status Variables in the Study Population Variable
Mean
Std. Dev. Median Minimum Maximum
BMI 22.51 4.50 22.40 Albumin (g/dL) 4.08 0.33 4.11 GNRI 103.0 11.1 103.3 12.5 2.4 12.4 Lean BMI (kg/m2) Percentage of 56.2 14.2 55.5 lean mass
12.60 3.05 64.6 6.2 30
36.75 4.89 132.4 18.5 97.9
BMI, body mass index; GNRI, geriatric nutritional risk index.
3
globin (P 5 .0186), creatinine (P 5 .0392), albumin (P 5 .0065), GNRI (P 5 .0274), and LBMI (P 5 .0274; Table 4). The prevalence of malnutrition according to albumin, GNRI (lowest quartile), and the LBMI (lowest quartile) differed significantly among the 3 appetite groups in the past 4 weeks (Fig. 1).
Discussion The early and accurate detection of a decreased appetite is important to the implementation of nutritional and medical interventions that can prevent PEM. The ADAT questionnaire is a practical tool for evaluating the relationship between appetite and dietary intake in hemodialysis patients.14 Appetite has been evaluated via the first question of ADAT (During the past week, how would you rate your appetite?), and it was observed an association with hospitalization23,24 as well as lower protein–energy intake and nutritional status marker levels.25 The question of KDQOL-SFÔ that addresses appetite during the past 4 weeks has been associated with a worse nutritional status, inflammation, depression, and increased risks of hospitalization and death.11 In the present study, decreased appetite in the past week was observed in 36% of patients, with 3.7%, 5.1%, and 27.2% reporting very poor, poor, and fair appetites, respectively. Kalantar-Zadeh et al26 reported a decreased appetite in 38% of the 331 patients studied according to the first question of the ADAT questionnaire; in that study, 0%, 7%, and 31% of the patients reported a very poor, poor, or fair appetite, respectively. In the Hemodialysis Study, one-third of the 1,846 patients included in the study reported a decreased appetite; 23.8% reported a fair appetite; and 8.8% reported a poor or very poor appetite.24 Regarding appetite in the past month, 28.7% of the patients in the present study reported a decreased appetite. Lopes et al11 observed that 23.9% of 14,406 studied patients reported a low appetite in the past month, with 14.4% reporting that they were moderately bothered, 14.6% that they were very much bothered, and 15.8% that they were extremely bothered by the lack of appetite. The degree of reduction in appetite might vary daily, and the literature indicates a trend toward a greater reduction in appetite on dialysis days.24,25 Some authors believe that the patient would be expected to experience improved appetite on the day of dialysis, particularly after dialysis, given the reduction in uremic toxins. Other authors argue that fatigue after dialysis might cause an appetite reduction, and that this fatigue might be caused by a higher rate of fluid removal and more frequent episodes of hypotension during dialysis.26 Additionally, when evaluating the results of the Hemodialysis Study, the prevalence of anorexia was related to the day on which the patient was undergoing dialysis.25 Burrowes et al, when considering the combined poor and very poor ADAT responses, reported a higher
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Table 3. Assessment of Demographic, Laboratory, and Nutritional Variables According to the Appetite Status in the Past Week (ADAT Question 1) Variable N Age Gender (male) Time on dialysis (mo) Dry weight (kg) Height (m) Hemoglobin Urea Creatinine Potassium Phosphorus Kt/V BMI Albumin (g/dL) GNRI Lean BMI (kg/m2)
Group 1
Group 2
Group 3
P
87 49.4 6 14.4 56.3% 76 6 60 57.7 6 12.1 1.59 6 0.07 12.2 6 1.5 124 6 30 10.0 6 2.6 5.0 6 0.7 5.0 6 1.5 1.57 6 0.36 22.87 6 4.53 4.09 6 0.31 103.8 6 11.9 12.8 6 2.5
37 51.5 6 18.1 62.2% 56 6 53 57.0 6 9.0 1.62 6 0.07 12.2 6 1.9 120 6 32 10.1 6 2.8 5.0 6 0.7 5.1 6 1.4 1.68 6 0.57 21.90 6 3.78 4.09 6 0.32 102.4 6 8.8 11.9 6 2.2
12 59.8 6 14.0 50% 58 6 59 57.8 6 20.2 1.62 6 0.12 11.6 6 2.4 123 6 35 8.6 6 3.9 5.0 6 0.8 5.2 6 1.9 1.55 6 0.37 21.85 6 6.20 3.91 6 0.49 99.6 6 16.6 11.6 6 2.9
.1009 .9969 .1780 .9506 .1800 .5463 .8271 .2038 .9840 .8427 .4046 .4790 .2032 .4450 .2827
BMI, body mass index; GNRI, geriatric nutritional risk index.
prevalence of anorexia on dialysis days (12.7%), whereas the prevalence was only 5.4% on days without dialysis. In the present study, the prevalence of low appetite on hemodialysis days did not differ from that on days without dialysis (11% and 10.3%), even when using the same criteria.25 The first question of the ADAT questionnaire, regarding appetite in the past week, indicated no association between the degree of appetite and nutritional parameters; this finding was similar to that of Kalantar-Zadeh et al.26 The latter authors also reported no correlation between the intensity of appetite and nutritional markers such as BMI, percentage of fat mass, skinfold measurement, and muscle circumference. In contrast, in the present study, the SFKDQOL question regarding appetite during the past
4 weeks revealed a significant association between the degree of appetite, which was classified into 3 groups, and the following nutritional variables: albumin (P 5 .0065), creatinine (P 5 .0392), GNRI (P 5 .0274), and LBMI (P 5.0274); the lower nutritional parameter values corresponded to the group with the lowest degree of appetite satisfaction. Lopes et al11 also previously used this question about appetite during the past 4 weeks and demonstrated significant differences in the levels of serum albumin, creatinine, BMI, and Kt/Vamong 5 appetite satisfaction groups. However, no significant differences were observed relative to the BMI, Kt/V, time on dialysis, and degree of appetite in the present study. Lopes et al11 also found no significant difference relative to the time on dialysis (P 5 .91).
Table 4. Assessment of Demographic, Laboratory, and Nutritional Variables According to the State of Appetite in the Past Four Weeks (KDQOL-SFTM) Variable N Age Male gender (%) Dialysis time (mo) Dry weight (kg) Height (m) Hemoglobin Urea Creatinine Potassium Phosphorus Kt/V BMI Albumin (g/dL) GNRI Lean BMI (kg/m2)
Group 1
Group 2
Group 3
P
97 50.1 6 16.1 60.8 66 6 53 58.9 6 12.3 1.60 6 0.08 12.3 6 1.50* 126 6 29 10.20 6 2.72* 5.0 6 0.7 5.2 6 1.6 1.57 6 0.46 22.9 6 4.6 4.11 6 0.32* 104.2 6 11.3* 13.0 6 2.5
27 52.4 6 15.1 55.6 75 6 66 54.8 6 8.7 1.58 6 0.08 12.5 6 2.1* 115 6 37 9.84 6 2.97 5.1 6 0.7 4.8 6 1.2 1.65 6 0.30 22.0 6 3.9 4.07 6 0.31* 102.2 6 8.6 11.2 6 1.9†
12 54.3 6 12.9 33.3 78 6 86 52.8 6 16.1 1.59 6 0.09 10.9 6 2.0 116 6 25 8.04 6 2.44 4.7 6 0.6 4.8 6 1.4 1.65 6 0.32 20.5 6 4.9 3.79 6 0.38 95.3 6 11.6 11.2 6 1.7
.5488 .1879 .6691 .1068 .4588 .0186 .1818 .0392* .3080 .0711 .6407 .1713 .0065* .0274* .0232*
BMI, body mass index; GNRI, geriatric nutritional risk index. *P , .05 versus group 3. †P , .05 versus group 1.
NUTRITIONAL MARKERS AND APPETITE IN DIALYSIS
Figure 1. Percentage of malnourished patients according to nutritional variables and degrees of appetite in the study population. BMI, body mass index; GNRI, geriatric nutritional risk index.
Carrero et al27 also reported a significant association between poor appetite and a worse nutritional status (e.g., lower serum concentrations of albumin, urea, creatinine, and insulin-like growth factor I) in a population of 223 hemodialysis patients. Poor appetite was also associated with a poorer anthropometric assessment (BMI and percentage fat mass). However, in that study, appetite was evaluated according to a question from the SGA,28 in which appetite is graded as either good, sometimes poor, often poor, or always poor. There is no gold standard for the detection of hemodialysis-related malnutrition, and screening methods such as the GNRI and bioelectrical impedance assessments have gained prominence in recent years. Among the parameters chosen to evaluate the nutritional status, the GNRI and percentage lean mass obtained via bioelectrical impedance had not been evaluated in previously published studies. In the present study, we found a significant correlation between the GNRI and altered appetite in the past 4 weeks; however, the literature is not unanimous regarding this index. GNRI was developed and validated by Bouillanne et al19, who modified the Nutritional Risk Index to facilitate its use in elderly subjects. The normal weight (variable present in the Nutritional Risk Index) is difficult to obtain in older patients, and accordingly, this parameter was replaced by the ideal weight in the GNRI. The applicability of the GNRI results from the fact that it is a practical tool to screen elderly patients for malnutrition.29 Szeto et al29 found that, in Chinese patients who were undergoing peritoneal dialysis, GNRI exhibited statistically significant correlations with other indicators of nutritional status such as the Malnutrition Inflammation Score and SGA. However, this correlation was modest and, according to the previously described study, the GNRI was not accurate as a malnutrition screening test in this group of patients, a finding that contrasted with the results reported by Yamanda et al.20 It could be argued that the GNRI was developed for elderly patients, and in the present study, all the patients independent of age were evaluated by the
5
GNRI. However, previously published studies also calculated GNRI to patients ,60 years on dialysis because the mean age was around 60 years but the standard deviation was 12.30 Although the GNRI was developed for elderly patients, both components of the GNRI—i.e., serum albumin and BMI—have been proven to correlate with morbidity and mortality in hemodialysis patients. Furthermore, these components have been shown to be representative of all aspects of nutrition, inflammation, and anemia in dialysis patients. The elements comprising lean mass are predominantly water, proteins, and minerals. Lean mass is calculated by subtracting the body fat from the total weight of the individual. Bioelectrical impedance is a rapid and noninvasive method to evaluate the body compartments.31 Lean tissues are good conductors of electric current given that they contain large amounts of water and electrolytes; accordingly, lean mass is easily estimated using bioelectrical impedance.32 In the present study, an association was observed between a decreased lean mass and low appetite; similar results have not been demonstrated in previous studies. Currently, bioelectrical impedance is not recommended by the K/DOQI guidelines (2000) for assessments of nutritional status in hemodialysis patients; although in the near future, this tool might be more widely used for this purpose.33 Regarding the demographic variables, the study by Lopes et al. 11 demonstrated an increased presence of anorexia in older patients, women, and individuals of African ancestry. Data have suggested that differences in the prevalence of anorexia according to gender might be mediated by gender-dependent cytokine and sex hormone responses.34 In the present study, the associations of appetite with age, gender, and race were not found to be significant. One limitation of the present study was the absence of a concomitant assessment of inflammatory markers as it is well known that the frequent occurrence of inflammation in hemodialysis patients might contribute to a poorer appetite and nutritional status. A state of chronic low-grade inflammation, characterized by increased levels of C-reactive protein and proinflammatory cytokines such as tumor necrosis factor a and interleukin 6, has been recognized as one of the most important PEM-related factors in patients with chronic kidney disease. This is because proinflammatory cytokines can increase protein catabolism and resting energy expenditure and may also affect appetite.35 The prevalence of chronic inflammation, as determined from the C-reactive protein levels, has been reported to range from 37% to 59% among Brazilian hemodialysis patients.36 The lack of data on dietary intake is another important limitation of the present study. A patient who reports reduction in appetite does not necessarily have a reduction in dietary intake. Possibly, many patients who referred reduction in appetite to ADAT question did not have a reduction in caloric and protein intakes, and some patients with reduced appetite may maintain an adequate
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OLIVEIRA ET AL
nutritional status by receiving nutritional supplements. This may explain why it was not observed strong association between degree of appetite in the past week and some nutritional indicators. Another limitation of the present study was the fact that this was a cross-sectional study that did not perform longitudinal assessments of the appetite and nutritional status, either of which could have positively or negatively affected the usefulness of the simple appetite self-assessment question. Additional studies are therefore needed to test this association during a follow-up of hemodialysis patients. One positive aspect of this study is the fact that, in Brazil, studies evaluating the prevalence of anorexia in hemodialysis patients and analyzing the associations between the degree of appetite and nutritional parameters had hitherto not been published. In conclusion, our findings suggest that the question of KDQOL addressing the bothering of lack of appetite in the last 4 weeks could be used as a malnutrition screening tool in hemodialysis patients as suggested by the correlation of decreased appetite in the last month with variables that assess nutritional status. However, the evaluation of appetite for a single question can be considered very subjective, and the answer may be doubtful because of the interference of other factors such as quality of life, presence of depression, socioeconomic level of the patient, and gender.
Practical Application Our findings confirmed the usefulness of appetite selfassessment questionnaire based on a single simple question that evaluated appetite in the last month but not in the last week in dialysis patients. The evaluation of appetite for a single question can be considered very subjective, and the answer may be doubtful because of the interference of other factors such as quality of life, presence of depression, socioeconomic level of the patient, and gender. The correlation of decreased appetite in the last month with variables that assess nutritional status suggest that this simple question can be used in the nutritional screening of dialysis patients.
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sclerosis (MIA syndrome) in chronic renal failure patients]. J Bras Nefrol. 2002;24:136-146. 7. Carrero JJ. Mechanisms of altered regulation of food intake in chronic kidney disease. J Ren Nutr. 2011;21:7-11. 8. Tisdale MJ. Biology of cachexia. J Natl Cancer Inst. 1997;89:1763-1773. 9. Carrero JJ, Aguilera A, Stenvinkel P, et al. Appetite disorders in uremia. J Ren Nutr. 2008;18:107-113. 10. Chung SH, Carrero JJ, Lindholm B. Causes of poor appetite in patients on peritoneal dialysis. J Ren Nutr. 2011;21:12-15. 11. Lopes AA, Elder SJ, Ginsberg N, et al. Lack of appetite in haemodialysis patients-associations with patient characteristics, indicators of nutritional status and outcomes in the international DOPPS. Nephrol Dial Transplant. 2007;22:3538-3546. 12. Buckner S, Dwyer J. Do we need a nutrition-specific quality of life questionnaire for dialysis patients? J Ren Nutr. 2003;13:295-302. 13. Carrero JJ. Identification of patients with eating disorders: clinical and biochemical signs of appetite loss in dialysis patients. J Ren Nutr. 2009; 19:10-15. 14. Burrowes JD, Powers SN, Cockram DB, et al. Use of an appetite and diet assessment tool in the pilot phase of a hemodialysis clinical trial: mortality and morbidity in hemodialysis study. J Ren Nutr. 1996;6:229-232. 15. Kalantar-Zadeh K, Kleiner M, Dunne E, et al. A modified quantitative subjective global assessment of nutrition for dialysis patients. Nephrol Dial Transplant. 1999;14:1732-1738. 16. Hays RD, Kallich JD, Mapes DL, et al. Development of the kidney disease quality of life (KDQOL) instrument. Qual Life Res. 1994;3:329-338. 17. Fouque D, Kalantar-Zadeh K, Kopple J, et al. A proposed nomenclature and diagnostic criteria for protein-energy wasting in acute and chronic kidney disease. Kidney Int. 2008;73:391-398. 18. Tietz NW, ed. Fundamentals of Clinical Chemistry. 3rd Edition Philadelphia, PA: W.B. Saunders; 1987. 19. Bouillanne O, Morineau G, Dupont C, et al. Geriatric Nutritional Risk Index: a new index for evaluating at-risk elderly medical patients. Am J Clin Nutr. 2005;82:777-783. 20. Yamada K, Furuya R, Takita T, et al. Simplified nutritional screening tools for patients on maintenance hemodialysis. Am J Clin Nutr. 2008;87: 106-113. 21. Machek P, Jirka T, Moissl U, et al. Guided optimization of fluid status in haemodialysis patients. Nephrol Dial Transplant. 2010;25:538-544. 22. Daugirdas JT. Simplified equations for monitoring Kt/V, PCRn, eKt/ V, and ePCRn. Adv Ren Replace Ther. 1995;2:295-304. 23. Bossola M, Giungi S, Luciani G, et al. Appetite in chronic haemodialysis patients: a longitudinal study. J Ren Nutr. 2009;19:372-379. 24. Burrowes JD, Larive B, Chertow GM, et al. Self-reported appetite, hospitalization and death in haemodialysis patients: findings from the Hemodialysis (HEMO) Study. Nephrol Dial Transplant. 2005;20: 2765-2774. 25. Burrowes JD, Larive B, Cockram DB, et al. Effects of dietary intake, appetite, and eating habits on dialysis and non-dialysis treatment days in hemodialysis patients: cross-sectional results from the HEMO study. J Ren Nutr. 2003;13:191-198. 26. Kalantar- Zadeh K, Block G, McAllister CJ, Humphreys MH, Kopple JD. Appetite and inflammation, nutrition, anemia, and clinical outcome in hemodialysis patients. Am J Clin Nutr. 2004;80:299-307. 27. Carrero JJ, Qureshi AR, Axelsson J, et al. Comparison of nutritional and inflammatory markers in dialysis patients with reduced appetite. Am J Clin Nutr. 2007;85:695-701. 28. Detsky AS, McLaughlin JR, Baker JP, et al. What is subjective global assessment of nutritional status? J Parent Ent Nutr. 1987;11:8-13. 29. Szeto CC, Kwan BC, Chow KM, et al. Geriatric nutritional risk index as a screening tool for malnutrition in patients on chronic peritoneal dialysis. J Ren Nutr. 2010;20:29-37. 30. Kobayashi I, Ishimura E, Kato Y, et al. Geriatric Nutritional Risk Index, a simplified nutritional screening index, is a significant predictor of mortality in chronic dialysis patients. Nephrol Dial Transplant. 2010;25:3361-3365.
NUTRITIONAL MARKERS AND APPETITE IN DIALYSIS 31. Kushner RF, De Vries PM, Gudivaka R. Use of bioelectrical impedance analysis measurements in the clinical management of patients undergoing dialysis. Am J Clin Nutr. 1996;64:503S-509S. 32. Kurtin PS, Shapiro AC, Tomita H, Raizman D. Volume status and body composition of chronic dialysis patients: utility of bioelectric impedance plethysmography. Am J Nephrol. 1990;10:363-367. 33. National Kidney Foundation: K/DOQI. Clinical Practice Guidelines for Nutrition in Chronic Renal Failure. Am J Kidney Dis. 2000;35(suppl 2):S1-S140.
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34. Geary N. Sex differences in disease anorexia. Nutrition. 2001;17: 499-507. 35. Lindholm B, Heimb€ urger O, Stenvinkel P. What are the causes of protein-energy malnutrition in chronic renal insufficiency? Am J Kidney Dis. 2002;39:422-425. 36. Nascimento MM, Pecoits-Filho R, Qureshi AR, et al. The prognostic impact of fluctuating levels of C-reactive protein in Brazilian hemodialysis patients: a prospective study. Nephrol Dial Transplant. 2004;19:2803-2809.
Correlation Between Nutritional Markers and Appetite Self-Assessments in Hemodialysis Patients Claudia M. C. Oliveira, PhD, Marcos Kubrusly, PhD, Andre. T. Lima, Danielle M. Torres, Natasha M. R. Cavalcante, Ant^onio L. C. Jer^onimo, MD, and Thiago. C. B. Oliveira Objective: Protein–energy malnutrition is among the comorbidities that most strongly affect the prognosis of patients with chronic kidney disease. Anorexia, defined as a loss of desire to eat, is one cause of such malnutrition. Tools that evaluate appetite and the correlation between appetite and nutritional parameters require further study. To evaluate the appetite status in patients from 2 hemodialysis clinics in Fortaleza, Brazil and the correlations between appetite (evaluated in the past week and in the past 4 weeks) and demographic, laboratory, and nutritional parameters. Methods: This was a cross-sectional study of patients aged $18 years who had undergone dialysis for .3 months. Appetite was evaluated using the first 3 questions of the Appetite and Diet Assessment Tool (ADAT) questionnaire, which evaluate the appetite status during the past week as well as 1 question from the Kidney Disease and Quality of LifeÔ Short Form that assesses appetite in the past 4 weeks. The patients were divided into 3 groups according to the degree of appetite: group 1: very good and good appetite (ADAT) or not and somewhat (Kidney Disease and Quality of LifeÔ Short Form); group 2: fair or moderately; and group 3: poor and very poor, or very much and extremely. The nutritional parameters evaluated were body mass index (BMI), serum albumin, Geriatric Nutritional Risk Index (GNRI) and lean body mass index (lean mass in kilogram per square meter) as obtained by multifrequency bioelectrical impedance analysis. Patients with a BMI ,23 kg/m2, albumin ,4 g/dL, GNRI ,98, and lean body mass index below the lowest quartile were considered malnourished. The associations between appetite and nutritional variables were tested using Fisher exact test and by comparing the means of the variables in the 3 groups using the analysis of variance and Kruskal–Wallis tests. Results: A total of 136 patients were included in the study with a mean age of 50.9 years and a median time on dialysis of 45 months; 57% of the patients were male. Regarding the first question on the ADAT questionnaire, 36% of patients exhibited anorexia in the past week. Furthermore, 28.7% of the population reported a lack of appetite in the last month. Moreover, 34.3% of the patients were considered malnourished according to BMI, 34.1% according to albumin, and 31.6% according to GNRI. Among the studied variables, the mean values of the following variables were different between groups 1, 2, and 3: hemoglobin (P 5 .0186), creatinine (P 5 .0392), albumin (P 5 .0065), GNRI (P 5 .0274), and lean BMI (P 5 .0274). Conclusions: The prevalence of a lack of appetite in hemodialysis patients in both the past week and the past month was high in the present study. The questionnaire evaluating appetite in the last 4 weeks could be used as a malnutrition screening tool in hemodialysis patients as suggested by the correlation of decreased appetite in the last month with variables that assess nutritional status such as albumin, lean body mass index, and GNRI. Ó 2015 by the National Kidney Foundation, Inc. All rights reserved.
P
Introduction
ROTEIN–ENERGY MALNUTRITION (PEM) is among the factors that most strongly affect the prognosis of patients with chronic kidney disease and is associated with increased morbidity and mortality even in the presence of adequate dialysis and protein intake.1-3 Studies have demonstrated evidence of malnutrition in 23% to 76% of hemodialysis patients and in 18% to 50% of patients undergoing peritoneal dialysis.4-6 The etiology of PEM is multifactorial and could be related to a concomitant Nephrology Department of Unichristus University, Fortaleza-Ceara, Brazil. Financial Disclosure: The authors declare that they have no relevant financial interests. Address correspondence to Claudia M.C. Oliveira, PhD, Centro Universitario de Medicina Christus, UniChristus, Universidade Federal do Ceara, Professor Jacinto Botelho Street 500, Fortaleza 60810-050, Ceara, Brazil. E-mail:
[email protected] Ó
2015 by the National Kidney Foundation, Inc. All rights reserved. 1051-2276/$36.00 http://dx.doi.org/10.1053/j.jrn.2014.09.006
Journal of Renal Nutrition, Vol -, No - (-), 2014: pp 1-7
inflammatory process, nutrient loss during dialysis, uremic endocrine disorders, low food intake, and anorexia.7 Anorexia is defined as the loss of desire to eat and is commonly observed in patients undergoing hemodialysis; this eating disorder contributes to the development of malnutrition and cachexia, poor quality of life, mortality, and hospitalization.8-10 Nutritional status assessment of dialysis patients and early detection of the causes of malnutrition are crucial to its prevention. There is no gold standard to evaluate the nutritional status of hemodialysis patients; however, in clinical practice, some methods have been suggested for this purpose such as the body mass index (BMI), serum albumin level, lean body mass (LBM), Geriatric Nutritional Risk Index (GNRI), and appetite assessment questionnaires.11,12 Appetite can easily be self-assessed by the patient through answering questions from different questionnaires such as the appetite and diet assessment tool (ADAT),13,14 Subjective Global Assessment (SGA)15 and the Kidney Disease Quality of Life Short Form (KDQOL-SF).16 The 1
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OLIVEIRA ET AL
ADAT was developed by the National Institutes of Health to evaluate appetite and the factors that affect food intake in hemodialysis patients in the past week; the first 3 questions address appetite.14 A question from the KDQOLSFÔ addresses appetite during the past 4 weeks. This single question regarding a lack of appetite has been associated with a worse nutritional status, inflammation, depression, and increased risks of hospitalization and death.11 Studies evaluating the prevalence of lack of appetite in hemodialysis patients and the relevance of questionnaires for anorexia diagnosis are scarce. An association between decreased appetite and some nutritional markers as BMI, creatinine, and albumin has been previously demonstrated, but more recent parameters such as GNRI and LBM assessed by bioelectrical impedance have not been studied. The present study aims to estimate the prevalence of anorexia in hemodialysis patients in 2 clinics in Fortaleza, Brazil according to 2 different questions and to evaluate the correlations between appetite and nutritional parameters.
Methods The study was conducted between July 2011 and July 2012. Patients aged $18 years who had undergone dialysis for .3 months were included in the study. The ability to respond to questionnaires and undergo anthropometric measurements in addition to providing signed informed consent forms was required. Pregnant women, patients with amputated limbs and paraplegics, in whom the application of bioelectrical impedance was not viable, were excluded. Appetite was evaluated using the first 3 questions of the ADAT questionnaire,14 which evaluate the appetite status during the last week (very good, good, fair, poor, or very poor) and whether there was a change in appetite in the last week (increased or decreased). An additional question from the KDQOL-SFÔ (version 1.3) was given to patients to evaluate their appetite during the past month (not at all bothered, somewhat bothered, moderately bothered, very much bothered, or extremely bothered).16 The responses ‘‘fair, poor, and very poor’’ on the ADAT and the responses ‘‘moderately bothered, very much bothered, and extremely bothered’’ on the KDQOL-SFÔ were defined as a lack of appetite (anorexia). For the statistical analysis, the patients were categorized into 3 groups according to their 5 possible answers to the 2 questions: group 1 (very good or good on ADAT/not at all bothered or somewhat bothered on the KDQOL-SFÔ); group 2 (fair on ADAT/moderately bothered on KDQOL-SFÔ); and group 3 (poor or very poor on ADAT/moderately to extremely bothered on KDQOL-SFÔ). The nutritional status of the patients was evaluated according to their BMI, serum albumin, GNRI, and LBM. The patients’ weights and heights were obtained after a dialysis session, and the BMI (kilogram per square meter) values
were subsequently calculated. Patients with a BMI ,23 kg/ m217 were considered malnourished. The albumin levels were measured during the predialysis period according to the bromocresol green method.18 Albumin levels ,4 g/dL were considered to indicate malnutrition.17 GNRI was calculated using the following equation: GNRI 5 [1.489 3 albumin (g/L)] 1 [41.7 3 weight/ideal weight].19,20 Ideal body weight was calculated according to the patient’s height and the ideal BMI of 22 kg/m2. The nutritional status was classified according to the following: GNRI ,82, severe malnutrition; GNRI 82 to 92, moderate malnutrition; GNRI 92 to 98, low risk; and GNRI .98, no risk. LBM was estimated via multifrequency bioelectrical impedance with a Body Composition Monitor device (Fresenius Medical Care, Bad Homburg vor der H€ ohe, Germany).21 Bioelectrical impedance was performed before initiating the dialysis session. Disposable electrodes were placed on the dorsal aspect of the wrist and on the third finger contralateral to the vascular access as well as on the anterior aspect of the ankle and on the third ipsilateral toe. The Body Composition Monitor report card data were transferred to the Dialysis Clinic’s microcomputer, which calculated lean and fat body masses. The index of lean body mass (LBMI) was calculated by dividing LBM by height squared. Patients with an LBMI below the lowest quartile were considered malnourished.17 The evaluated demographic data included age, gender, and time on dialysis. The variables related to dialysis treatment included the frequency and duration of treatment, type of vascular access, and adequacy of dialysis as estimated by Kt/V. Kt/V was obtained via 2-point urea kinetics modeling.22 Other evaluated laboratory variables included hemoglobin, urea, creatinine, potassium, and phosphorus.
Statistical Analysis The SPSS 20.0 (IBM Corp, Armonk, NY) software was used for the statistical analysis. Continuous variables are expressed as means 6 standard deviations, and the categorical variables are expressed as a frequency or a percentage. The association between the nutritional variables and the degree of appetite was assessed by comparing the mean values of the variables in the 3 groups using one-way analysis of variance followed by Bonferroni test. A P value , .05 was considered significant.
Results A total of 136 patients were included in this study, of whom 57% were male; the mean age was 50.9 years, and the median time on dialysis was 45 months. The demographic characteristics, dialysis treatment, and laboratory data of the study population are shown in Table 1. According to the ADAT, the appetite in the past week was very good in 11.8% of patients, good in 52.2%, fair
NUTRITIONAL MARKERS AND APPETITE IN DIALYSIS Table 1. Demographic, Dialysis Treatment, and Laboratory Characteristics of the Studied Patients Variable Age Gender Time on dialysis (mo) Duration of dialysis (h) Dry weight (kg) Height (m) Hemoglobin Urea Creatinine Potassium Phosphorus Kt/V
Mean
Std. Dev.
50.9 Male: 57% 69 4.0 57.5 1.60 12.2 123 9.9 5.0 5.0 1.60
15.6 Female: 43% 59 0.2 12.2 0.08 1.7 30 2.8 0.7 15 0.42
in 27.2%, poor in 5.1%, and very poor in 3.7%. Furthermore, 22% of the patients reported a change in appetite in the past week (n 5 30); the appetite increased in 13 patients (43.3%) and decreased in 17 patients (56.7%). According to the KDQOL-SFÔ question regarding the past month, 18.4% of patients reported being not at all bothered by a lack of appetite, 52.9% were somewhat bothered, 19.9% were moderately bothered, 5.9% were very much bothered, and 2.9% were extremely bothered. In summary, the prevalence of decreased appetite was 36% in the past week according to ADAT question 1 and 28.7% in the past 4 weeks according to KDQOL-SFÔ question. There was no significant difference between the prevalence of lack of appetite on days with (36%) and without dialysis (38.2%). The nutritional status variables are listed in Table 2. The results showed that 34.3% of the patients were considered malnourished according to the BMI, 34.1% according to albumin levels, 31.6% according to GNRI, and 24.6% according to the LBMI. There were no significant differences between the degree of appetite in the past week (groups 1, 2, and 3) with respect to the study variables (Table 3). A time on dialysis $60 months was observed in 50.5%, 27%, and 25% of patients in groups 1, 2, and 3, respectively (P 5.024). When assessing the degree of appetite in the past 4 weeks, the results showed significant differences between groups 1, 2, and 3 for mean values of the following variables: hemoTable 2. Nutritional Status Variables in the Study Population Variable
Mean
Std. Dev. Median Minimum Maximum
BMI 22.51 4.50 22.40 Albumin (g/dL) 4.08 0.33 4.11 GNRI 103.0 11.1 103.3 12.5 2.4 12.4 Lean BMI (kg/m2) Percentage of 56.2 14.2 55.5 lean mass
12.60 3.05 64.6 6.2 30
36.75 4.89 132.4 18.5 97.9
BMI, body mass index; GNRI, geriatric nutritional risk index.
3
globin (P 5 .0186), creatinine (P 5 .0392), albumin (P 5 .0065), GNRI (P 5 .0274), and LBMI (P 5 .0274; Table 4). The prevalence of malnutrition according to albumin, GNRI (lowest quartile), and the LBMI (lowest quartile) differed significantly among the 3 appetite groups in the past 4 weeks (Fig. 1).
Discussion The early and accurate detection of a decreased appetite is important to the implementation of nutritional and medical interventions that can prevent PEM. The ADAT questionnaire is a practical tool for evaluating the relationship between appetite and dietary intake in hemodialysis patients.14 Appetite has been evaluated via the first question of ADAT (During the past week, how would you rate your appetite?), and it was observed an association with hospitalization23,24 as well as lower protein–energy intake and nutritional status marker levels.25 The question of KDQOL-SFÔ that addresses appetite during the past 4 weeks has been associated with a worse nutritional status, inflammation, depression, and increased risks of hospitalization and death.11 In the present study, decreased appetite in the past week was observed in 36% of patients, with 3.7%, 5.1%, and 27.2% reporting very poor, poor, and fair appetites, respectively. Kalantar-Zadeh et al26 reported a decreased appetite in 38% of the 331 patients studied according to the first question of the ADAT questionnaire; in that study, 0%, 7%, and 31% of the patients reported a very poor, poor, or fair appetite, respectively. In the Hemodialysis Study, one-third of the 1,846 patients included in the study reported a decreased appetite; 23.8% reported a fair appetite; and 8.8% reported a poor or very poor appetite.24 Regarding appetite in the past month, 28.7% of the patients in the present study reported a decreased appetite. Lopes et al11 observed that 23.9% of 14,406 studied patients reported a low appetite in the past month, with 14.4% reporting that they were moderately bothered, 14.6% that they were very much bothered, and 15.8% that they were extremely bothered by the lack of appetite. The degree of reduction in appetite might vary daily, and the literature indicates a trend toward a greater reduction in appetite on dialysis days.24,25 Some authors believe that the patient would be expected to experience improved appetite on the day of dialysis, particularly after dialysis, given the reduction in uremic toxins. Other authors argue that fatigue after dialysis might cause an appetite reduction, and that this fatigue might be caused by a higher rate of fluid removal and more frequent episodes of hypotension during dialysis.26 Additionally, when evaluating the results of the Hemodialysis Study, the prevalence of anorexia was related to the day on which the patient was undergoing dialysis.25 Burrowes et al, when considering the combined poor and very poor ADAT responses, reported a higher
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OLIVEIRA ET AL
Table 3. Assessment of Demographic, Laboratory, and Nutritional Variables According to the Appetite Status in the Past Week (ADAT Question 1) Variable N Age Gender (male) Time on dialysis (mo) Dry weight (kg) Height (m) Hemoglobin Urea Creatinine Potassium Phosphorus Kt/V BMI Albumin (g/dL) GNRI Lean BMI (kg/m2)
Group 1
Group 2
Group 3
P
87 49.4 6 14.4 56.3% 76 6 60 57.7 6 12.1 1.59 6 0.07 12.2 6 1.5 124 6 30 10.0 6 2.6 5.0 6 0.7 5.0 6 1.5 1.57 6 0.36 22.87 6 4.53 4.09 6 0.31 103.8 6 11.9 12.8 6 2.5
37 51.5 6 18.1 62.2% 56 6 53 57.0 6 9.0 1.62 6 0.07 12.2 6 1.9 120 6 32 10.1 6 2.8 5.0 6 0.7 5.1 6 1.4 1.68 6 0.57 21.90 6 3.78 4.09 6 0.32 102.4 6 8.8 11.9 6 2.2
12 59.8 6 14.0 50% 58 6 59 57.8 6 20.2 1.62 6 0.12 11.6 6 2.4 123 6 35 8.6 6 3.9 5.0 6 0.8 5.2 6 1.9 1.55 6 0.37 21.85 6 6.20 3.91 6 0.49 99.6 6 16.6 11.6 6 2.9
.1009 .9969 .1780 .9506 .1800 .5463 .8271 .2038 .9840 .8427 .4046 .4790 .2032 .4450 .2827
BMI, body mass index; GNRI, geriatric nutritional risk index.
prevalence of anorexia on dialysis days (12.7%), whereas the prevalence was only 5.4% on days without dialysis. In the present study, the prevalence of low appetite on hemodialysis days did not differ from that on days without dialysis (11% and 10.3%), even when using the same criteria.25 The first question of the ADAT questionnaire, regarding appetite in the past week, indicated no association between the degree of appetite and nutritional parameters; this finding was similar to that of Kalantar-Zadeh et al.26 The latter authors also reported no correlation between the intensity of appetite and nutritional markers such as BMI, percentage of fat mass, skinfold measurement, and muscle circumference. In contrast, in the present study, the SFKDQOL question regarding appetite during the past
4 weeks revealed a significant association between the degree of appetite, which was classified into 3 groups, and the following nutritional variables: albumin (P 5 .0065), creatinine (P 5 .0392), GNRI (P 5 .0274), and LBMI (P 5.0274); the lower nutritional parameter values corresponded to the group with the lowest degree of appetite satisfaction. Lopes et al11 also previously used this question about appetite during the past 4 weeks and demonstrated significant differences in the levels of serum albumin, creatinine, BMI, and Kt/Vamong 5 appetite satisfaction groups. However, no significant differences were observed relative to the BMI, Kt/V, time on dialysis, and degree of appetite in the present study. Lopes et al11 also found no significant difference relative to the time on dialysis (P 5 .91).
Table 4. Assessment of Demographic, Laboratory, and Nutritional Variables According to the State of Appetite in the Past Four Weeks (KDQOL-SFTM) Variable N Age Male gender (%) Dialysis time (mo) Dry weight (kg) Height (m) Hemoglobin Urea Creatinine Potassium Phosphorus Kt/V BMI Albumin (g/dL) GNRI Lean BMI (kg/m2)
Group 1
Group 2
Group 3
P
97 50.1 6 16.1 60.8 66 6 53 58.9 6 12.3 1.60 6 0.08 12.3 6 1.50* 126 6 29 10.20 6 2.72* 5.0 6 0.7 5.2 6 1.6 1.57 6 0.46 22.9 6 4.6 4.11 6 0.32* 104.2 6 11.3* 13.0 6 2.5
27 52.4 6 15.1 55.6 75 6 66 54.8 6 8.7 1.58 6 0.08 12.5 6 2.1* 115 6 37 9.84 6 2.97 5.1 6 0.7 4.8 6 1.2 1.65 6 0.30 22.0 6 3.9 4.07 6 0.31* 102.2 6 8.6 11.2 6 1.9†
12 54.3 6 12.9 33.3 78 6 86 52.8 6 16.1 1.59 6 0.09 10.9 6 2.0 116 6 25 8.04 6 2.44 4.7 6 0.6 4.8 6 1.4 1.65 6 0.32 20.5 6 4.9 3.79 6 0.38 95.3 6 11.6 11.2 6 1.7
.5488 .1879 .6691 .1068 .4588 .0186 .1818 .0392* .3080 .0711 .6407 .1713 .0065* .0274* .0232*
BMI, body mass index; GNRI, geriatric nutritional risk index. *P , .05 versus group 3. †P , .05 versus group 1.
NUTRITIONAL MARKERS AND APPETITE IN DIALYSIS
Figure 1. Percentage of malnourished patients according to nutritional variables and degrees of appetite in the study population. BMI, body mass index; GNRI, geriatric nutritional risk index.
Carrero et al27 also reported a significant association between poor appetite and a worse nutritional status (e.g., lower serum concentrations of albumin, urea, creatinine, and insulin-like growth factor I) in a population of 223 hemodialysis patients. Poor appetite was also associated with a poorer anthropometric assessment (BMI and percentage fat mass). However, in that study, appetite was evaluated according to a question from the SGA,28 in which appetite is graded as either good, sometimes poor, often poor, or always poor. There is no gold standard for the detection of hemodialysis-related malnutrition, and screening methods such as the GNRI and bioelectrical impedance assessments have gained prominence in recent years. Among the parameters chosen to evaluate the nutritional status, the GNRI and percentage lean mass obtained via bioelectrical impedance had not been evaluated in previously published studies. In the present study, we found a significant correlation between the GNRI and altered appetite in the past 4 weeks; however, the literature is not unanimous regarding this index. GNRI was developed and validated by Bouillanne et al19, who modified the Nutritional Risk Index to facilitate its use in elderly subjects. The normal weight (variable present in the Nutritional Risk Index) is difficult to obtain in older patients, and accordingly, this parameter was replaced by the ideal weight in the GNRI. The applicability of the GNRI results from the fact that it is a practical tool to screen elderly patients for malnutrition.29 Szeto et al29 found that, in Chinese patients who were undergoing peritoneal dialysis, GNRI exhibited statistically significant correlations with other indicators of nutritional status such as the Malnutrition Inflammation Score and SGA. However, this correlation was modest and, according to the previously described study, the GNRI was not accurate as a malnutrition screening test in this group of patients, a finding that contrasted with the results reported by Yamanda et al.20 It could be argued that the GNRI was developed for elderly patients, and in the present study, all the patients independent of age were evaluated by the
5
GNRI. However, previously published studies also calculated GNRI to patients ,60 years on dialysis because the mean age was around 60 years but the standard deviation was 12.30 Although the GNRI was developed for elderly patients, both components of the GNRI—i.e., serum albumin and BMI—have been proven to correlate with morbidity and mortality in hemodialysis patients. Furthermore, these components have been shown to be representative of all aspects of nutrition, inflammation, and anemia in dialysis patients. The elements comprising lean mass are predominantly water, proteins, and minerals. Lean mass is calculated by subtracting the body fat from the total weight of the individual. Bioelectrical impedance is a rapid and noninvasive method to evaluate the body compartments.31 Lean tissues are good conductors of electric current given that they contain large amounts of water and electrolytes; accordingly, lean mass is easily estimated using bioelectrical impedance.32 In the present study, an association was observed between a decreased lean mass and low appetite; similar results have not been demonstrated in previous studies. Currently, bioelectrical impedance is not recommended by the K/DOQI guidelines (2000) for assessments of nutritional status in hemodialysis patients; although in the near future, this tool might be more widely used for this purpose.33 Regarding the demographic variables, the study by Lopes et al. 11 demonstrated an increased presence of anorexia in older patients, women, and individuals of African ancestry. Data have suggested that differences in the prevalence of anorexia according to gender might be mediated by gender-dependent cytokine and sex hormone responses.34 In the present study, the associations of appetite with age, gender, and race were not found to be significant. One limitation of the present study was the absence of a concomitant assessment of inflammatory markers as it is well known that the frequent occurrence of inflammation in hemodialysis patients might contribute to a poorer appetite and nutritional status. A state of chronic low-grade inflammation, characterized by increased levels of C-reactive protein and proinflammatory cytokines such as tumor necrosis factor a and interleukin 6, has been recognized as one of the most important PEM-related factors in patients with chronic kidney disease. This is because proinflammatory cytokines can increase protein catabolism and resting energy expenditure and may also affect appetite.35 The prevalence of chronic inflammation, as determined from the C-reactive protein levels, has been reported to range from 37% to 59% among Brazilian hemodialysis patients.36 The lack of data on dietary intake is another important limitation of the present study. A patient who reports reduction in appetite does not necessarily have a reduction in dietary intake. Possibly, many patients who referred reduction in appetite to ADAT question did not have a reduction in caloric and protein intakes, and some patients with reduced appetite may maintain an adequate
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OLIVEIRA ET AL
nutritional status by receiving nutritional supplements. This may explain why it was not observed strong association between degree of appetite in the past week and some nutritional indicators. Another limitation of the present study was the fact that this was a cross-sectional study that did not perform longitudinal assessments of the appetite and nutritional status, either of which could have positively or negatively affected the usefulness of the simple appetite self-assessment question. Additional studies are therefore needed to test this association during a follow-up of hemodialysis patients. One positive aspect of this study is the fact that, in Brazil, studies evaluating the prevalence of anorexia in hemodialysis patients and analyzing the associations between the degree of appetite and nutritional parameters had hitherto not been published. In conclusion, our findings suggest that the question of KDQOL addressing the bothering of lack of appetite in the last 4 weeks could be used as a malnutrition screening tool in hemodialysis patients as suggested by the correlation of decreased appetite in the last month with variables that assess nutritional status. However, the evaluation of appetite for a single question can be considered very subjective, and the answer may be doubtful because of the interference of other factors such as quality of life, presence of depression, socioeconomic level of the patient, and gender.
Practical Application Our findings confirmed the usefulness of appetite selfassessment questionnaire based on a single simple question that evaluated appetite in the last month but not in the last week in dialysis patients. The evaluation of appetite for a single question can be considered very subjective, and the answer may be doubtful because of the interference of other factors such as quality of life, presence of depression, socioeconomic level of the patient, and gender. The correlation of decreased appetite in the last month with variables that assess nutritional status suggest that this simple question can be used in the nutritional screening of dialysis patients.
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