J Nutr Health Aging
THE JOURNAL OF NUTRITION, HEALTH & AGING©
MULTIMORBIDITY TYPE, HOSPITALIZATIONS AND EMERGENCY DEPARTMENT VISITS AMONG NURSING HOME RESIDENTS: A PRELIMINARY STUDY. P. DE SOUTO BARRETO1,2, M. LAPEYRE-MESTRE3,4, B. VELLAS1,3, Y. ROLLAND1,3 1. Gérontopôle de Toulouse, Institut du Vieillissement, Centre Hospitalo-Universitaire de Toulouse (CHU Toulouse), Toulouse, France; 2. UMR7268 ADES, Aix-Marseille Univ., Marseille, France; 3. UMR INSERM 1027, University of Toulouse III, Toulouse, France; 4. Service de Pharmacologie Clinique, CHU de Toulouse, Toulouse, France. Corresponding author: Philipe de Souto Barreto. Gérontopôle de Toulouse, Institut du Vieillissement. 37, Allées Jules Guesde, F-31073 Toulouse, France. Telephone number: (+33) 561 145 664, Fax: (+33) 561 145 640, E-mail: [email protected]
Abstract: Background: The burden of multimorbidity in institutionalized elderly is poorly investigated. We examined the associations of the type of multimorbidity (i.e., physical, mental or both) with the number of hospitalizations and emergency department (ED) visits in nursing home (NH) residents. Methods: This is a crosssectional study among NH residents. Information on residents’ health, number of hospitalizations in the last 12 months and hospital department of admission (having been seen in ED vs. non) was recorded by NH staff of 175 French NHs (data was collected in 2011). Participants were screened for the presence of several mental (e.g., dementia) and physical conditions (e.g., diabetes). Results: Data on hospitalization was available for 6076 NH residents. Compared to having no diseases, the concomitant presence of ≥ 2 physical conditions was the multimorbidity type more strongly associated with both the number of hospitalizations (incidence rate ratio (IRR) =1.93; 95% confidence interval (CI) =1.57 – 2.37) and ED visits (odds ratio (OR)= 1.79; 95% CI=1.24 – 2.58). The presence of a mental condition appeared to moderate the associations between physical conditions and hospitalizations, since the estimate effects were lower among people who had both physical and mental conditions, compared to those with only physical conditions. For example, compared to people with ≥ 2 physical conditions, those with multiple physical and mental conditions had lower IRR (IRR = 0.84; 95% CI=0.75 – 0.95) for the number of hospitalizations. Conclusions: Mental diseases in very old and multimorbid NH residents probably moderate the associations between physical diseases and hospitalizations. To what extent this represents either a mirror of better clinical practice in NHs or the under-recognition from the NH staff of symptoms leading to justifiable hospitalizations remains unclear. Key words: Older adults, multimorbidity, nursing home, hospitalization, emergency department.
Introduction
Methods
Research on multimorbidity in older people is scarce (1). Recently, a panel of experts proposed a set of health outcomes to be addressed in multimorbid patients (2), and concluded that gaps remain regarding the evaluation of disease burden and cognitive function in such a complex population. Although some studies have investigated the burden of co-morbid diseases in older adults (1), most of them investigated the association between specific diseases, such as depression and diabetes or heart diseases (3, 4). Despite its relevance for individuals’ health and the health system, multimorbidity in older adults living in NHs has been poorly investigated (5). Yet, NH residents are characterized by the presence of several concomitant diseases, multiple medications (6-8), and an increased use of health care services (9), which increase their risk of developing adverse health outcomes. To our knowledge, no study has quantified the risk of hospitalizations and emergency department (ED) visits according with the type of multimorbidity (i.e., mental, physical, or a mix between mental and physical diseases) in very old residents of NHs. We therefore investigated the burden of multimorbidity type by examining the associations of multimorbidity with the total number of hospitalizations and the probability of ED visits in a large sample of NH residents.
This work used the baseline data (cross-sectional design) from the IQUARE study; data was collected in 2011 and analyzed in 2012/2013. IQUARE’s protocol was fully described elsewhere (7); it will be briefly reported herein. IQUARE is a multicentric individually-tailored controlled trial developed in NHs from Midi-Pyrénées, South-Western, France (trial registration number: NCT01703689). This is a 6-month intervention, with a 18-month follow-up, designed to improve NH quality indicators. NHs were allocated to one of the following two groups: 1) audit and feedback intervention on quality indicators associated to cooperative work meetings between hospital geriatricians and NH staff, or 2) audit and feedback only. IQUARE followed the principles of the Declaration of Helsinki and complied with ethical standards in France; study protocol was approved by the ethic committee of the Toulouse University Hospital and the Consultative Committee for the Treatment of Research Information on Health (CNIL: 07-438). Since the functioning and integration of NHs in the whole health system vary among countries, we will briefly describe how it operates in France. In this country, each registered NH is required to have a coordinating physician among its staff
Received October 28, 2013 Accepted for publication December 16, 2013
1
J Nutr Health Aging
DEPRESSION AND MULTIMORBIDITY IN NURSING HOMES members; this coordinating physician, generally a geriatrician, is responsible for comprehensive health evaluation of each NH resident and for health care coordination. Drug prescription remains under the responsibility of the resident’s primary care physician. Participants A total of 6275 residents from 175 NHs participate in IQUARE. People were randomly selected (excepted for NHs that had ≤ 30 potential participants, in which all residents were included in the study) on the basis of alphabetical order within each NH: NHs having between 31 and 90 residents had to randomly select (at a pace of 1 / 2 persons) from 30 to 45 participants; NHs with > 90 residents had to randomly select from 45 to 60 participants (at a pace of 1 / 3 persons). Participants were 86 years-old (±8.2) and were mostly women (73.7%). Outcomes The main outcome measures were the number of hospitalizations (i.e., the number of times participants were seen in the hospital) in the last 12 months (discrete variable) and ED visits (binary variable: people who were not seen in ED in the last 12 months vs. people who were seen in ED). Procedures Participants were screened for the presence of: 1) physical conditions. cancer, diabetes, pain, stroke, myocardial infarction, congestive heart failure, peripheral vascular disease, and chronic pulmonary disease; 2) mental conditions. dementia, psychiatric diseases (other than depression), and depression. Information on residents’ health status, including diseases’ screening, was obtained through an on-line questionnaire completed by the NH medical staff, mainly the coordinating physician; this questionnaire was completed on the basis of information contained in the patients’ medical charts. These diseases were selected due to their high burden to the society according with information from a recent report on multimorbidity of the Institute of Medicine (1). The selection of diseases to be included was limited by data availability in the IQUARE study: therefore some diseases, such as osteoarthritis or atrial fibrillation, were not selected because there were no data on these conditions. Participants were then divided into one of the following “multimorbid groups”: none (none of the physical and mental diseases described above, n=495), only 1 physical condition (PC1, n=678), only 1 mental condition (MC1, n=960), ≥2 physical conditions (PC2, n=781), ≥2 mental conditions (MC2, n=497), 1 mental and 1 physical condition (PMC1, n= 971), or multiple physical and mental conditions (MPMC, n=1893. People in this group had both physical and mental conditions for a minimum of 3 diseases). “Multimorbid groups” constitutes our independent variable of interest. Information on medical conditions, the number of hospitalizations and ED visits were reported by the NH 2
coordinating physician. It is important to note that, for the purposes of public funding in France, residents’ diseases reported by the NH coordinating physician are regularly evaluated to confirm their exactness. This medical control, which is made by a physician from the Regional Agency of Health by consulting the medical charts of a fraction of the NH residents, supports the reliability of our data. Confounders Individual-related variables: age, sex, disability in activities of daily living (measured using a 6-item scale (e.g., bathing, toileting) – scores vary from 6 to 18, with higher scores indicating higher disability), use of antipsychotics, antidepressants, anxiolytics, hypnotics/sedatives, number of medications (summation of drugs other than those indicated before), history of fractures in vertebra, hip, femur, or wrist (single dichotomy: yes vs. no), falls in the last year (yes vs. no), living in a special care unit in the NH, weight change in the last two months (weight maintenance, loss, or gain), and the following diseases (each disease being a binary variable “yes” vs. “no”): hypertension, hemiplegia, peptic ulcer, liver disease, connective tissue disease, moderate/severe kidney failure, and epilepsy. NH-related variables. ownership (public, private non-profit, or private for-profit), NH geographical localization (rural, lowurbanized, intermediate-urbanized, or highly urbanized), fulltime equivalent per 100 NH beds for coordinating physician, for nurses, and for nurses’ aide. Statistical Analysis We reported incidence rate ratios (IRR) with 95% confidence intervals (CIs) after performing a mixed-effects Poisson regression on the number of hospitalizations; this procedure allowed us to adjust the model for the fact of living in a particular NH (variable entered as a random effect). For the binary variable “ED visits”, we reported odds ratios (OR) with 95% CI after performing a mixed-effects binary logistic regression (living in a particular NH entered into the model as a random effect). Potential multicollinearity was checked by using the variance inflation factor (VIF). Multivariate models contained the variable “multimorbid groups” and all the confounders. All analyses were performed using Stata version 11 (College Station, TX: StataCorp LP). Results Data on the number of hospitalizations were available for 6076 individuals (n=199 missing data). A total of 1944 subjects totalized 2921 hospitalizations in the last 12 months: 1119 persons had been admitted in the ED, 707 in other departments, and 4132 were not hospitalized (information about the department of admission was lacking for 118 hospitalized subjects). The distribution of hospitalizations according with multimorbid groups gave the following results (mean ±
J Nutr Health Aging
THE JOURNAL OF NUTRITION, HEALTH & AGING© standard deviation): “no diseases” had an average of 0.2 (±0.6) multicollinearity was probably not an issue since VIF values hospitalizations, with 11.3% of participants (n=54) having been were < 2 for all independent variables in the models (mean VIF seen in ED; “PC1” 0.4 (±0.9) hospitalizations, with 16% = 1.12). Table 1 shows the mixed-effects Poisson regression on (n=105) of ED visits; “MC1” 0.3 (±0.7) hospitalizations, with the number of hospitalizations. As expected, adjusted analysis 13.1% (n=121) of ED visits; “PC2” 0.7 (±1.3) hospitalizations, showed that the IRRs were higher for almost all multimorbid with 22.7% (n=172) of ED visits; “MC2” 0.4 (±0.8), with groups compared to “none” (except for the group MC1). 17.6% (n=85) of ED visits; “PMC1” 0.4 (±0.8), with 18.7% Moreover, it is interesting to note that the IRRs for the “only (n=176) of ED visits; “MPMC” 0.6 (±1.0), with 22.1% (n=406) physical conditions” groups (i.e., PC1 and PC2) were higher than the IRRs for the groups with a mix of physical and mental of ED visits. The prevalence of chronic conditions was: cancer – 12.7% diseases (i.e., PMC1 and MPMC): people with one physical (n=799), diabetes – 15.8% (n=992), pain – 23.4% (n=1467), condition (PC1) had a IRR of 1.36 whereas those with both one stroke – 12.7% (n=795), myocardial infarction – 7.5% (n=472), physical and one mental condition (PMC1) had a IRR of 1.29; congestive heart failure – 19.4% (n=1219), peripheral vascular the same trend was found when comparing the group PC2 with disease – 17.9% (n=1122) and chronic pulmonary disease – the group MPMC. Table 2 displays the results of the mixed-effects binary 10.3% (n=645), dementia – 42.8% (n=2688), depression – 34.2% (n=2148) and psychiatric disease (other than depression) logistic regression on ED visits. Adjusted analysis showed that – 17.6% (n=1107). Participants were staying in the NH for people in the multiple physical conditions group (PC2) and longer than 41 months (median [25th – 75th percentiles]=1240 those in the multiple physical and mental conditions (MPMC) group had higher probabilities of having been seen in ED, [527–2330] days). With regards to the multivariate regression models, compared to those in the “no diseases” group. As it was found Table 1 Impact of multimorbidity on the number of hospitalizations among nursing home residents using mixed-effects Poisson regression Unadjusted model (n=6076)* IRR (95% CI) P Value Multimorbidity (ref. none) PC1 MC1 PC2 MC2 PMC1 MPMC
1.58 (1.27 – 1.96) 1.19 (0.96 – 1.47) 2.57 (2.1 – 3.14) 1.68 (1.34 – 2.11) 1.67 (1.35 – 2.05) 2.35 (1.94 – 2.84)
< 0.001 0.117 < 0.001 < 0.001 < 0.001 < 0.001
Adjusted model (n=6002)† IRR (95% CI) P Value 1.36 (1.09 – 1.69) 1.01 (0.81 – 1.26) 1.93 (1.57 – 2.37) 1.41 (1.17 – 1.79) 1.29 (1.05 – 1.60) 1.63 (1.33 – 1.99)
0.006 0.91 < 0.001 0.004 0.017 < 0.001
*The unadjusted model contained only the variable “multimorbid groups”, estimated as a fixed effect, and the fact of living in a particular nursing home, estimated as a random effect. †The adjusted model contained the variables of the unadjusted model and all the confounders. Note: CI, confidence interval; IRR, incidence rate ratio; PC1, only 1 physical conditions; MC1, only 1 mental condition; PC2, ≥ 2 physical conditions; MC2, ≥ 2 mental conditions; PMC, 1 physical + 1 mental conditions; MPMC, multiple physical and mental conditions.
Table 2 Impact of multimorbidity on emergency department visits among nursing home residents using mixed-effects logistic regression Unadjusted model (n=6076)* OR (95% CI) P Value Multimorbidity (ref. none) PC1 MC1 PC2 MC2 PMC1 MPMC
1.55 (1.08 – 2.22) 1.22 (0.85 – 1.73) 2.38 (1.69 – 3.36) 1.78 (1.21 – 2.60) 1.91 (1.36 – 2.68) 2.33 (1.69 – 3.20)
0.018 0.28 < 0.001 0.003 < 0.001 < 0.001
Adjusted model (n=6002)† OR (95% CI) P Value 1.33 (0.91 – 1.95) 0.98 (0.67 – 1.43) 1.79 (1.24 – 2.58) 1.50 (0.99 – 2.28) 1.39 (0.96 – 2.00) 1.48 (1.04 – 2.10)
0.15 0.92 0.002 0.054 0.078 0.029
*The unadjusted model contained only the variable “multimorbid groups”, estimated as a fixed effect, and the fact of living in a particular nursing home, estimated as a random effect. †The adjusted model contained the variables of the unadjusted model and all the confounders. Note: CI, confidence interval; ED, emergency department; OR, odds ratio; PC1, only 1 physical conditions; MC1, only 1 mental condition; PC2, ≥ 2 physical conditions; MC2, ≥ 2 mental conditions; PMC, 1 physical + 1 mental conditions; MPMC, multiple physical and mental conditions.
3
J Nutr Health Aging
DEPRESSION AND MULTIMORBIDITY IN NURSING HOMES for the outcome “number of hospitalizations”, PC2 group had a OR of having been seen in ED higher than the OR for the MPMC group. On the basis of the unexpected results showing that people with only physical conditions had higher probabilities of hospitalizations and ED visits than people with both physical and mental conditions, we decided to further explore the differences in hospitalization-related variables according with multimorbidity type. For this, we ran exploratory analyses by performing the same adjusted regressions than before and changing the reference category to oppose the group PC1 against the group PMC1, and to oppose the group PC2 against the group MPMC. Mixed-effects Poisson regressions showed that, compared to PC1 (reference category), PMC1 group was not significantly associated with the number of hospitalizations (IRR = 0.95; 95% CI=0.81 – 1.12; p=0.56); however, the MPMC group had lower IRR (IRR = 0.84; 95% CI=0.75 – 0.95; p=0.005) for the number of hospitalizations, compared to the PC2 (reference category) group. For ED visits, mixedeffects logistic regressions showed the same pattern for the comparison between the groups PC1 (reference category) and PMC1 (OR = 1.04; 95% CI=0.77 – 1.41; p=0.77); the MPMC group (OR = 0.83; 95% CI=0.65 – 1.06; p=0.13) tended to have a lower probability of being seen in ED compared to the PC2 (reference category) group. We then examined if these results could be explained by a higher disease burden (as measured by the Charlson Comorbidity Index (10) in the groups PC1 vs. PMC and PC2 vs. MPMC: student t-test for independent samples showed that the groups PMC1 (1.9 ± 1.5) and MPMC (3.3 ± 1.9) had higher scores in the Charlson comorbidity index than the groups PC1 (1.6 ± 1.8) and PC2 (3.2 ± 2.3), respectively (statistically significant differences only for the PMC1 vs. PC1 comparison; p
THE JOURNAL OF NUTRITION, HEALTH & AGING©
MULTIMORBIDITY TYPE, HOSPITALIZATIONS AND EMERGENCY DEPARTMENT VISITS AMONG NURSING HOME RESIDENTS: A PRELIMINARY STUDY. P. DE SOUTO BARRETO1,2, M. LAPEYRE-MESTRE3,4, B. VELLAS1,3, Y. ROLLAND1,3 1. Gérontopôle de Toulouse, Institut du Vieillissement, Centre Hospitalo-Universitaire de Toulouse (CHU Toulouse), Toulouse, France; 2. UMR7268 ADES, Aix-Marseille Univ., Marseille, France; 3. UMR INSERM 1027, University of Toulouse III, Toulouse, France; 4. Service de Pharmacologie Clinique, CHU de Toulouse, Toulouse, France. Corresponding author: Philipe de Souto Barreto. Gérontopôle de Toulouse, Institut du Vieillissement. 37, Allées Jules Guesde, F-31073 Toulouse, France. Telephone number: (+33) 561 145 664, Fax: (+33) 561 145 640, E-mail: [email protected]
Abstract: Background: The burden of multimorbidity in institutionalized elderly is poorly investigated. We examined the associations of the type of multimorbidity (i.e., physical, mental or both) with the number of hospitalizations and emergency department (ED) visits in nursing home (NH) residents. Methods: This is a crosssectional study among NH residents. Information on residents’ health, number of hospitalizations in the last 12 months and hospital department of admission (having been seen in ED vs. non) was recorded by NH staff of 175 French NHs (data was collected in 2011). Participants were screened for the presence of several mental (e.g., dementia) and physical conditions (e.g., diabetes). Results: Data on hospitalization was available for 6076 NH residents. Compared to having no diseases, the concomitant presence of ≥ 2 physical conditions was the multimorbidity type more strongly associated with both the number of hospitalizations (incidence rate ratio (IRR) =1.93; 95% confidence interval (CI) =1.57 – 2.37) and ED visits (odds ratio (OR)= 1.79; 95% CI=1.24 – 2.58). The presence of a mental condition appeared to moderate the associations between physical conditions and hospitalizations, since the estimate effects were lower among people who had both physical and mental conditions, compared to those with only physical conditions. For example, compared to people with ≥ 2 physical conditions, those with multiple physical and mental conditions had lower IRR (IRR = 0.84; 95% CI=0.75 – 0.95) for the number of hospitalizations. Conclusions: Mental diseases in very old and multimorbid NH residents probably moderate the associations between physical diseases and hospitalizations. To what extent this represents either a mirror of better clinical practice in NHs or the under-recognition from the NH staff of symptoms leading to justifiable hospitalizations remains unclear. Key words: Older adults, multimorbidity, nursing home, hospitalization, emergency department.
Introduction
Methods
Research on multimorbidity in older people is scarce (1). Recently, a panel of experts proposed a set of health outcomes to be addressed in multimorbid patients (2), and concluded that gaps remain regarding the evaluation of disease burden and cognitive function in such a complex population. Although some studies have investigated the burden of co-morbid diseases in older adults (1), most of them investigated the association between specific diseases, such as depression and diabetes or heart diseases (3, 4). Despite its relevance for individuals’ health and the health system, multimorbidity in older adults living in NHs has been poorly investigated (5). Yet, NH residents are characterized by the presence of several concomitant diseases, multiple medications (6-8), and an increased use of health care services (9), which increase their risk of developing adverse health outcomes. To our knowledge, no study has quantified the risk of hospitalizations and emergency department (ED) visits according with the type of multimorbidity (i.e., mental, physical, or a mix between mental and physical diseases) in very old residents of NHs. We therefore investigated the burden of multimorbidity type by examining the associations of multimorbidity with the total number of hospitalizations and the probability of ED visits in a large sample of NH residents.
This work used the baseline data (cross-sectional design) from the IQUARE study; data was collected in 2011 and analyzed in 2012/2013. IQUARE’s protocol was fully described elsewhere (7); it will be briefly reported herein. IQUARE is a multicentric individually-tailored controlled trial developed in NHs from Midi-Pyrénées, South-Western, France (trial registration number: NCT01703689). This is a 6-month intervention, with a 18-month follow-up, designed to improve NH quality indicators. NHs were allocated to one of the following two groups: 1) audit and feedback intervention on quality indicators associated to cooperative work meetings between hospital geriatricians and NH staff, or 2) audit and feedback only. IQUARE followed the principles of the Declaration of Helsinki and complied with ethical standards in France; study protocol was approved by the ethic committee of the Toulouse University Hospital and the Consultative Committee for the Treatment of Research Information on Health (CNIL: 07-438). Since the functioning and integration of NHs in the whole health system vary among countries, we will briefly describe how it operates in France. In this country, each registered NH is required to have a coordinating physician among its staff
Received October 28, 2013 Accepted for publication December 16, 2013
1
J Nutr Health Aging
DEPRESSION AND MULTIMORBIDITY IN NURSING HOMES members; this coordinating physician, generally a geriatrician, is responsible for comprehensive health evaluation of each NH resident and for health care coordination. Drug prescription remains under the responsibility of the resident’s primary care physician. Participants A total of 6275 residents from 175 NHs participate in IQUARE. People were randomly selected (excepted for NHs that had ≤ 30 potential participants, in which all residents were included in the study) on the basis of alphabetical order within each NH: NHs having between 31 and 90 residents had to randomly select (at a pace of 1 / 2 persons) from 30 to 45 participants; NHs with > 90 residents had to randomly select from 45 to 60 participants (at a pace of 1 / 3 persons). Participants were 86 years-old (±8.2) and were mostly women (73.7%). Outcomes The main outcome measures were the number of hospitalizations (i.e., the number of times participants were seen in the hospital) in the last 12 months (discrete variable) and ED visits (binary variable: people who were not seen in ED in the last 12 months vs. people who were seen in ED). Procedures Participants were screened for the presence of: 1) physical conditions. cancer, diabetes, pain, stroke, myocardial infarction, congestive heart failure, peripheral vascular disease, and chronic pulmonary disease; 2) mental conditions. dementia, psychiatric diseases (other than depression), and depression. Information on residents’ health status, including diseases’ screening, was obtained through an on-line questionnaire completed by the NH medical staff, mainly the coordinating physician; this questionnaire was completed on the basis of information contained in the patients’ medical charts. These diseases were selected due to their high burden to the society according with information from a recent report on multimorbidity of the Institute of Medicine (1). The selection of diseases to be included was limited by data availability in the IQUARE study: therefore some diseases, such as osteoarthritis or atrial fibrillation, were not selected because there were no data on these conditions. Participants were then divided into one of the following “multimorbid groups”: none (none of the physical and mental diseases described above, n=495), only 1 physical condition (PC1, n=678), only 1 mental condition (MC1, n=960), ≥2 physical conditions (PC2, n=781), ≥2 mental conditions (MC2, n=497), 1 mental and 1 physical condition (PMC1, n= 971), or multiple physical and mental conditions (MPMC, n=1893. People in this group had both physical and mental conditions for a minimum of 3 diseases). “Multimorbid groups” constitutes our independent variable of interest. Information on medical conditions, the number of hospitalizations and ED visits were reported by the NH 2
coordinating physician. It is important to note that, for the purposes of public funding in France, residents’ diseases reported by the NH coordinating physician are regularly evaluated to confirm their exactness. This medical control, which is made by a physician from the Regional Agency of Health by consulting the medical charts of a fraction of the NH residents, supports the reliability of our data. Confounders Individual-related variables: age, sex, disability in activities of daily living (measured using a 6-item scale (e.g., bathing, toileting) – scores vary from 6 to 18, with higher scores indicating higher disability), use of antipsychotics, antidepressants, anxiolytics, hypnotics/sedatives, number of medications (summation of drugs other than those indicated before), history of fractures in vertebra, hip, femur, or wrist (single dichotomy: yes vs. no), falls in the last year (yes vs. no), living in a special care unit in the NH, weight change in the last two months (weight maintenance, loss, or gain), and the following diseases (each disease being a binary variable “yes” vs. “no”): hypertension, hemiplegia, peptic ulcer, liver disease, connective tissue disease, moderate/severe kidney failure, and epilepsy. NH-related variables. ownership (public, private non-profit, or private for-profit), NH geographical localization (rural, lowurbanized, intermediate-urbanized, or highly urbanized), fulltime equivalent per 100 NH beds for coordinating physician, for nurses, and for nurses’ aide. Statistical Analysis We reported incidence rate ratios (IRR) with 95% confidence intervals (CIs) after performing a mixed-effects Poisson regression on the number of hospitalizations; this procedure allowed us to adjust the model for the fact of living in a particular NH (variable entered as a random effect). For the binary variable “ED visits”, we reported odds ratios (OR) with 95% CI after performing a mixed-effects binary logistic regression (living in a particular NH entered into the model as a random effect). Potential multicollinearity was checked by using the variance inflation factor (VIF). Multivariate models contained the variable “multimorbid groups” and all the confounders. All analyses were performed using Stata version 11 (College Station, TX: StataCorp LP). Results Data on the number of hospitalizations were available for 6076 individuals (n=199 missing data). A total of 1944 subjects totalized 2921 hospitalizations in the last 12 months: 1119 persons had been admitted in the ED, 707 in other departments, and 4132 were not hospitalized (information about the department of admission was lacking for 118 hospitalized subjects). The distribution of hospitalizations according with multimorbid groups gave the following results (mean ±
J Nutr Health Aging
THE JOURNAL OF NUTRITION, HEALTH & AGING© standard deviation): “no diseases” had an average of 0.2 (±0.6) multicollinearity was probably not an issue since VIF values hospitalizations, with 11.3% of participants (n=54) having been were < 2 for all independent variables in the models (mean VIF seen in ED; “PC1” 0.4 (±0.9) hospitalizations, with 16% = 1.12). Table 1 shows the mixed-effects Poisson regression on (n=105) of ED visits; “MC1” 0.3 (±0.7) hospitalizations, with the number of hospitalizations. As expected, adjusted analysis 13.1% (n=121) of ED visits; “PC2” 0.7 (±1.3) hospitalizations, showed that the IRRs were higher for almost all multimorbid with 22.7% (n=172) of ED visits; “MC2” 0.4 (±0.8), with groups compared to “none” (except for the group MC1). 17.6% (n=85) of ED visits; “PMC1” 0.4 (±0.8), with 18.7% Moreover, it is interesting to note that the IRRs for the “only (n=176) of ED visits; “MPMC” 0.6 (±1.0), with 22.1% (n=406) physical conditions” groups (i.e., PC1 and PC2) were higher than the IRRs for the groups with a mix of physical and mental of ED visits. The prevalence of chronic conditions was: cancer – 12.7% diseases (i.e., PMC1 and MPMC): people with one physical (n=799), diabetes – 15.8% (n=992), pain – 23.4% (n=1467), condition (PC1) had a IRR of 1.36 whereas those with both one stroke – 12.7% (n=795), myocardial infarction – 7.5% (n=472), physical and one mental condition (PMC1) had a IRR of 1.29; congestive heart failure – 19.4% (n=1219), peripheral vascular the same trend was found when comparing the group PC2 with disease – 17.9% (n=1122) and chronic pulmonary disease – the group MPMC. Table 2 displays the results of the mixed-effects binary 10.3% (n=645), dementia – 42.8% (n=2688), depression – 34.2% (n=2148) and psychiatric disease (other than depression) logistic regression on ED visits. Adjusted analysis showed that – 17.6% (n=1107). Participants were staying in the NH for people in the multiple physical conditions group (PC2) and longer than 41 months (median [25th – 75th percentiles]=1240 those in the multiple physical and mental conditions (MPMC) group had higher probabilities of having been seen in ED, [527–2330] days). With regards to the multivariate regression models, compared to those in the “no diseases” group. As it was found Table 1 Impact of multimorbidity on the number of hospitalizations among nursing home residents using mixed-effects Poisson regression Unadjusted model (n=6076)* IRR (95% CI) P Value Multimorbidity (ref. none) PC1 MC1 PC2 MC2 PMC1 MPMC
1.58 (1.27 – 1.96) 1.19 (0.96 – 1.47) 2.57 (2.1 – 3.14) 1.68 (1.34 – 2.11) 1.67 (1.35 – 2.05) 2.35 (1.94 – 2.84)
< 0.001 0.117 < 0.001 < 0.001 < 0.001 < 0.001
Adjusted model (n=6002)† IRR (95% CI) P Value 1.36 (1.09 – 1.69) 1.01 (0.81 – 1.26) 1.93 (1.57 – 2.37) 1.41 (1.17 – 1.79) 1.29 (1.05 – 1.60) 1.63 (1.33 – 1.99)
0.006 0.91 < 0.001 0.004 0.017 < 0.001
*The unadjusted model contained only the variable “multimorbid groups”, estimated as a fixed effect, and the fact of living in a particular nursing home, estimated as a random effect. †The adjusted model contained the variables of the unadjusted model and all the confounders. Note: CI, confidence interval; IRR, incidence rate ratio; PC1, only 1 physical conditions; MC1, only 1 mental condition; PC2, ≥ 2 physical conditions; MC2, ≥ 2 mental conditions; PMC, 1 physical + 1 mental conditions; MPMC, multiple physical and mental conditions.
Table 2 Impact of multimorbidity on emergency department visits among nursing home residents using mixed-effects logistic regression Unadjusted model (n=6076)* OR (95% CI) P Value Multimorbidity (ref. none) PC1 MC1 PC2 MC2 PMC1 MPMC
1.55 (1.08 – 2.22) 1.22 (0.85 – 1.73) 2.38 (1.69 – 3.36) 1.78 (1.21 – 2.60) 1.91 (1.36 – 2.68) 2.33 (1.69 – 3.20)
0.018 0.28 < 0.001 0.003 < 0.001 < 0.001
Adjusted model (n=6002)† OR (95% CI) P Value 1.33 (0.91 – 1.95) 0.98 (0.67 – 1.43) 1.79 (1.24 – 2.58) 1.50 (0.99 – 2.28) 1.39 (0.96 – 2.00) 1.48 (1.04 – 2.10)
0.15 0.92 0.002 0.054 0.078 0.029
*The unadjusted model contained only the variable “multimorbid groups”, estimated as a fixed effect, and the fact of living in a particular nursing home, estimated as a random effect. †The adjusted model contained the variables of the unadjusted model and all the confounders. Note: CI, confidence interval; ED, emergency department; OR, odds ratio; PC1, only 1 physical conditions; MC1, only 1 mental condition; PC2, ≥ 2 physical conditions; MC2, ≥ 2 mental conditions; PMC, 1 physical + 1 mental conditions; MPMC, multiple physical and mental conditions.
3
J Nutr Health Aging
DEPRESSION AND MULTIMORBIDITY IN NURSING HOMES for the outcome “number of hospitalizations”, PC2 group had a OR of having been seen in ED higher than the OR for the MPMC group. On the basis of the unexpected results showing that people with only physical conditions had higher probabilities of hospitalizations and ED visits than people with both physical and mental conditions, we decided to further explore the differences in hospitalization-related variables according with multimorbidity type. For this, we ran exploratory analyses by performing the same adjusted regressions than before and changing the reference category to oppose the group PC1 against the group PMC1, and to oppose the group PC2 against the group MPMC. Mixed-effects Poisson regressions showed that, compared to PC1 (reference category), PMC1 group was not significantly associated with the number of hospitalizations (IRR = 0.95; 95% CI=0.81 – 1.12; p=0.56); however, the MPMC group had lower IRR (IRR = 0.84; 95% CI=0.75 – 0.95; p=0.005) for the number of hospitalizations, compared to the PC2 (reference category) group. For ED visits, mixedeffects logistic regressions showed the same pattern for the comparison between the groups PC1 (reference category) and PMC1 (OR = 1.04; 95% CI=0.77 – 1.41; p=0.77); the MPMC group (OR = 0.83; 95% CI=0.65 – 1.06; p=0.13) tended to have a lower probability of being seen in ED compared to the PC2 (reference category) group. We then examined if these results could be explained by a higher disease burden (as measured by the Charlson Comorbidity Index (10) in the groups PC1 vs. PMC and PC2 vs. MPMC: student t-test for independent samples showed that the groups PMC1 (1.9 ± 1.5) and MPMC (3.3 ± 1.9) had higher scores in the Charlson comorbidity index than the groups PC1 (1.6 ± 1.8) and PC2 (3.2 ± 2.3), respectively (statistically significant differences only for the PMC1 vs. PC1 comparison; p
