DIABETICMedicine
Letters DOI: 10.1111/dme.12419
Depressive symptoms and HbA1c in patients with Type 1 and Type 2 diabetes Diabet. Med. 31, 759–760 (2014)
Bot et al. [1] conducted a cross-sectional and 1-year follow-up study to predict HbA1c by depressive symptoms using the Patient Health Questionnaire 9-item version (PHQ-9) in patients, aged ≥ 18 years, with Type 1 (n = 277) or Type 2 (n = 365) diabetes. The authors used multiple regression analysis to adjust for sex, age, education, ethnic minority, insulin treatment, BMI and smoking. As a main result of the follow-up study, significant positive relationships were observed in patients with Type 1 diabetes between HbA1c and PHQ-9 items such as sleeping difficulties, appetite problems, concentration problems and psychomotor changes. I have some concerns regarding this study. First, the prevalence of depression is higher in patients with Type 1 diabetes [2] and depression is closely related to inadequate glycaemic control in patients with Type 1 diabetes [3]. Although Bot et al. used PHQ-9 as a substitute for the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), to specify major depressive disorder, the authors only used nine components of the PHQ-9 to predict HbA1c. The PHQ-9 is used either as a diagnostic algorithm to make a screening of major depressive disorder or as a continuous measure, with PHQ-9 scores ranging from 0 to 27 to classify the severity of depressive symptoms [4]. When a diagnostic algorithm is selected, major depressive disorder was considered in patients who endorse five or more of the nine symptoms as present, with more than half the days and at least one of the first two symptoms (lack of interest or depressed mood) endorsed. Although the authors selected the cut-off value of ≥ 10 as an elevated depressive symptom by quoting a reference [5], they did not use it as an independent variable for multivariate analysis. Not only components of PHQ-9, but also depressive status by PHQ-9 should be included to clarify predictors of HbA1c. As a second concern, the authors clarified the association between sleeping difficulties and HbA1c. Borel et al. [6] reported that short sleep duration of < 6.5 h, vs. sleep duration of ≥ 6.5 h, by wrist actigraph, was associated with higher levels of HbA1c in 79 patients with Type 1 diabetes by multivariable regression analysis. Unfortunately, the U-shaped relationship between sleep duration and HbA1c value that had been observed in Type 2 diabetes was not
ª 2014 The Authors. Diabetic Medicine ª 2014 Diabetes UK
reported [7]. In addition, sleeping difficulties are determined by the elongation of sleep latency, disturbance of sleep maintenance and early morning awakening. Sleep duration is one indicator of sleep quality, and validity of actigraphy should be validated by other methods, including sleep polysomnography [8]. Johnson et al. [9] recently conducted a systematic review on the association between depression and Type 1 diabetes in young people up to 25 years old. Evidence from the previous 10 years was inconclusive regarding whether there is an increased prevalence of depression among young adults with Type 1 diabetes, although there was a tendency towards patients who were more depressed having a higher HbA1c level. Bot et al. dealt with patients (aged ≥ 18 years) and two indispensable symptoms such as ‘lack of interest’ and ‘depressed mood’ were not selected as significant predictors of HbA1c in patients with Type 1 or Type 2 diabetes. As the authors concluded, continuous assessment is recommended to know the causality of the association.
Funding sources
None.
Competing interests
None declared. T. Kawada Department of Hygiene and Public Health, Nippon Medical School, Tokyo, Japan
References 1 Bot M, Pouwer F, de Jonge P, Tack CJ, Geelhoed-Duijvestijn PH, Snoek FJ. Differential associations between depressive symptoms and glycaemic control in outpatients with diabetes. Diabet Med 2013; 30: e115–122. 2 Roy T, Lloyd CE. Epidemiology of depression and diabetes: a systematic review. J Affect Disord 2012; 142: S8–21. 3 Melin EO, Thunander M, Svensson R, Landin-Olsson M, Thulesius HO. Depression, obesity and smoking were independently associated with inadequate glycemic control in patients with type 1 diabetes. Eur J Endocrinol 2013; 168: 861–869. 4 Kroenke K, Spitzer RL, Williams JB, Lowe B. The Patient Health Questionnaire Somatic, Anxiety, and Depressive Symptom Scales: a systematic review. Gen Hosp Psychiatry 2010; 32: 345–359. 5 Kroenke K, Spitzer RL, Williams JB. The PHQ-9: validity of a brief depression severity measure. J Gen Intern Med 2001; 16: 606–613. 6 Borel AL, Pepin JL, Nasse L, Baguet JP, Netter S, Benhamou PY. Short sleep duration measured by wrist actimetry is associated with
759
DIABETICMedicine
deteriorated glycemic control in type 1 diabetes. Diabetes Care 2013; 36: 2902–2908. 7 Koren D. Levitt Katz LE, Brar PC, Gallagher PR, Berkowitz RI, Brooks LJ. Sleep architecture and glucose and insulin homeostasis in obese adolescents. Diabetes Care 2011; 34: 2442–2447. 8 Sadeh A. The role and validity of actigraphy in sleep medicine: an update. Sleep Med Rev 2011; 15: 259–267. 9 Johnson B, Eiser C, Young V, Brierley S, Heller S. Prevalence of depression among young people with Type 1 diabetes: a systematic review. Diabet Med 2013; 30: 199–208.
DOI: 10.1111/dme.12421
Response to Kawada. Depressive symptoms and HbA1c in patients with Type 1 and Type 2 diabetes Diabet. Med. 31, 760–761 (2014) We thank Kawada for raising several concerns [1] about our paper ‘Differential associations between depressive symptoms and glycaemic control in outpatients with diabetes’ [2]. First, Kawada discusses the use of the Patient Health Questionnaire (PHQ-9) instrument in our study. In addition to the individual symptoms of depression, Kawada points out that the association of depression and HbA1c should be studied using the diagnostic algorithm of the PHQ-9 to classify major depressive disorder. The relationship between major depressive disorder and HbA1c in diabetes has been the topic of many papers, including a meta-analysis that showed a positive association between depression and HbA1c [3]. Depression is, however, a very heterogeneous construct, and persons with depression can differ substantially in the symptoms they express. Therefore, instead of looking at the overall depression construct, the specific purpose of the study was to study the relationship between the individual symptoms of depression and HbA1c in patients with diabetes. We did not report nor intend to propose that the individual symptoms of the PHQ-9 can be used as a substitute for the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) major depressive disorder. Although the approach suggested by Kawada would provide further evidence for the potential relationship between depression and HbA1c, this would not result in differentiation of depression at the symptom level. Second, Kawada regrets that we did not discuss the potential U-shaped relationship between sleep duration and HbA1c, which has been observed in obese adolescents [4]. We believe that this specific study supports many observations that both short and long sleep duration appear to be related to poorer health in general [5,6]. Although we could only devote a limited amount of words to this important topic in the discussion section of our paper, it would be interesting to investigate the direction of the relationship between sleep duration and HbA1c. We completely agree with Kawada’s
760
Letters
suggestion to include more valid measurement of sleep quality in studies that investigate the relationship between sleep and glycaemic control, which has been carried out in the very recent study of Borel et al. [7]. Finally, Kawada incorrectly pointed out that lack of interest and depressed mood were not related to HbA1c. As shown in table 2 [2], depressed mood was a significant predictor for HbA1c in the overall sample and in individuals with Type 1 diabetes. We hope that our analysis and Kawada’s comments spur future longitudinal research that will further expand our understanding of the potential bidirectional relationship of depressive symptoms and glycaemic control in people with diabetes. We believe that the heterogenic nature of depression should not be overlooked here and may help to guide research and interventions for improving both mental health and glycaemic control in individuals with diabetes.
Funding sources
None.
Competing interests
None declared. M. Bot1, F. Pouwer2, P. de Jonge3 and F. Snoek4 Department of Psychiatry and the EMGO Institute for Health and Care Research, VU University Medical Centre, and GGZ inGeest, Amsterdam, 2Department of Medical and Clinical Psychology, Center of Research on Psychology in Somatic Diseases CoRPS, Tilburg University, Tilburg, 3Interdisciplinary Centre for Psychiatric Epidemiology, University Medical Centre Groningen, Groningen and 4Diabetes Psychology Research Group, Department of Medical Psychology, EMGO-Institute, VU University Medical Centre, Amsterdam, the Netherlands 1
References 1 Kawada T. Depressive symptoms and HbA1c in patients with Type 1 and Type 2 diabetes. Diabet Med 2014; 31: 759–760. 2 Bot M, Pouwer F, de Jonge P, Tack CJ, Geelhoed-Duijvestijn PHLM, Snoek FJ. Differential associations between depressive symptoms and glycaemic control in outpatients with diabetes. Diabet Med 2013; 30: e115–e122. 3 Lustman PJ, Anderson RJ, Freedland KE, de Groot M, Carney RM, Clouse RE. Depression and poor glycemic control: a meta-analytic review of the literature. Diabetes Care 2000; 23: 934–942. 4 Koren D. Levitt Katz LE, Brar PC, Gallagher PR, Berkowitz RI, Brooks LJ. Sleep architecture and glucose and insulin homeostasis in obese adolescents. Diabetes Care 2011; 34: 2442–2447. 5 Ayas NT, White DP, Manson JE, Stampfer MJ, Speizer FE, Malhotra A et al. A prospective study of sleep duration and
ª 2014 The Authors. Diabetic Medicine ª 2014 Diabetes UK
Letters DOI: 10.1111/dme.12419
Depressive symptoms and HbA1c in patients with Type 1 and Type 2 diabetes Diabet. Med. 31, 759–760 (2014)
Bot et al. [1] conducted a cross-sectional and 1-year follow-up study to predict HbA1c by depressive symptoms using the Patient Health Questionnaire 9-item version (PHQ-9) in patients, aged ≥ 18 years, with Type 1 (n = 277) or Type 2 (n = 365) diabetes. The authors used multiple regression analysis to adjust for sex, age, education, ethnic minority, insulin treatment, BMI and smoking. As a main result of the follow-up study, significant positive relationships were observed in patients with Type 1 diabetes between HbA1c and PHQ-9 items such as sleeping difficulties, appetite problems, concentration problems and psychomotor changes. I have some concerns regarding this study. First, the prevalence of depression is higher in patients with Type 1 diabetes [2] and depression is closely related to inadequate glycaemic control in patients with Type 1 diabetes [3]. Although Bot et al. used PHQ-9 as a substitute for the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), to specify major depressive disorder, the authors only used nine components of the PHQ-9 to predict HbA1c. The PHQ-9 is used either as a diagnostic algorithm to make a screening of major depressive disorder or as a continuous measure, with PHQ-9 scores ranging from 0 to 27 to classify the severity of depressive symptoms [4]. When a diagnostic algorithm is selected, major depressive disorder was considered in patients who endorse five or more of the nine symptoms as present, with more than half the days and at least one of the first two symptoms (lack of interest or depressed mood) endorsed. Although the authors selected the cut-off value of ≥ 10 as an elevated depressive symptom by quoting a reference [5], they did not use it as an independent variable for multivariate analysis. Not only components of PHQ-9, but also depressive status by PHQ-9 should be included to clarify predictors of HbA1c. As a second concern, the authors clarified the association between sleeping difficulties and HbA1c. Borel et al. [6] reported that short sleep duration of < 6.5 h, vs. sleep duration of ≥ 6.5 h, by wrist actigraph, was associated with higher levels of HbA1c in 79 patients with Type 1 diabetes by multivariable regression analysis. Unfortunately, the U-shaped relationship between sleep duration and HbA1c value that had been observed in Type 2 diabetes was not
ª 2014 The Authors. Diabetic Medicine ª 2014 Diabetes UK
reported [7]. In addition, sleeping difficulties are determined by the elongation of sleep latency, disturbance of sleep maintenance and early morning awakening. Sleep duration is one indicator of sleep quality, and validity of actigraphy should be validated by other methods, including sleep polysomnography [8]. Johnson et al. [9] recently conducted a systematic review on the association between depression and Type 1 diabetes in young people up to 25 years old. Evidence from the previous 10 years was inconclusive regarding whether there is an increased prevalence of depression among young adults with Type 1 diabetes, although there was a tendency towards patients who were more depressed having a higher HbA1c level. Bot et al. dealt with patients (aged ≥ 18 years) and two indispensable symptoms such as ‘lack of interest’ and ‘depressed mood’ were not selected as significant predictors of HbA1c in patients with Type 1 or Type 2 diabetes. As the authors concluded, continuous assessment is recommended to know the causality of the association.
Funding sources
None.
Competing interests
None declared. T. Kawada Department of Hygiene and Public Health, Nippon Medical School, Tokyo, Japan
References 1 Bot M, Pouwer F, de Jonge P, Tack CJ, Geelhoed-Duijvestijn PH, Snoek FJ. Differential associations between depressive symptoms and glycaemic control in outpatients with diabetes. Diabet Med 2013; 30: e115–122. 2 Roy T, Lloyd CE. Epidemiology of depression and diabetes: a systematic review. J Affect Disord 2012; 142: S8–21. 3 Melin EO, Thunander M, Svensson R, Landin-Olsson M, Thulesius HO. Depression, obesity and smoking were independently associated with inadequate glycemic control in patients with type 1 diabetes. Eur J Endocrinol 2013; 168: 861–869. 4 Kroenke K, Spitzer RL, Williams JB, Lowe B. The Patient Health Questionnaire Somatic, Anxiety, and Depressive Symptom Scales: a systematic review. Gen Hosp Psychiatry 2010; 32: 345–359. 5 Kroenke K, Spitzer RL, Williams JB. The PHQ-9: validity of a brief depression severity measure. J Gen Intern Med 2001; 16: 606–613. 6 Borel AL, Pepin JL, Nasse L, Baguet JP, Netter S, Benhamou PY. Short sleep duration measured by wrist actimetry is associated with
759
DIABETICMedicine
deteriorated glycemic control in type 1 diabetes. Diabetes Care 2013; 36: 2902–2908. 7 Koren D. Levitt Katz LE, Brar PC, Gallagher PR, Berkowitz RI, Brooks LJ. Sleep architecture and glucose and insulin homeostasis in obese adolescents. Diabetes Care 2011; 34: 2442–2447. 8 Sadeh A. The role and validity of actigraphy in sleep medicine: an update. Sleep Med Rev 2011; 15: 259–267. 9 Johnson B, Eiser C, Young V, Brierley S, Heller S. Prevalence of depression among young people with Type 1 diabetes: a systematic review. Diabet Med 2013; 30: 199–208.
DOI: 10.1111/dme.12421
Response to Kawada. Depressive symptoms and HbA1c in patients with Type 1 and Type 2 diabetes Diabet. Med. 31, 760–761 (2014) We thank Kawada for raising several concerns [1] about our paper ‘Differential associations between depressive symptoms and glycaemic control in outpatients with diabetes’ [2]. First, Kawada discusses the use of the Patient Health Questionnaire (PHQ-9) instrument in our study. In addition to the individual symptoms of depression, Kawada points out that the association of depression and HbA1c should be studied using the diagnostic algorithm of the PHQ-9 to classify major depressive disorder. The relationship between major depressive disorder and HbA1c in diabetes has been the topic of many papers, including a meta-analysis that showed a positive association between depression and HbA1c [3]. Depression is, however, a very heterogeneous construct, and persons with depression can differ substantially in the symptoms they express. Therefore, instead of looking at the overall depression construct, the specific purpose of the study was to study the relationship between the individual symptoms of depression and HbA1c in patients with diabetes. We did not report nor intend to propose that the individual symptoms of the PHQ-9 can be used as a substitute for the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) major depressive disorder. Although the approach suggested by Kawada would provide further evidence for the potential relationship between depression and HbA1c, this would not result in differentiation of depression at the symptom level. Second, Kawada regrets that we did not discuss the potential U-shaped relationship between sleep duration and HbA1c, which has been observed in obese adolescents [4]. We believe that this specific study supports many observations that both short and long sleep duration appear to be related to poorer health in general [5,6]. Although we could only devote a limited amount of words to this important topic in the discussion section of our paper, it would be interesting to investigate the direction of the relationship between sleep duration and HbA1c. We completely agree with Kawada’s
760
Letters
suggestion to include more valid measurement of sleep quality in studies that investigate the relationship between sleep and glycaemic control, which has been carried out in the very recent study of Borel et al. [7]. Finally, Kawada incorrectly pointed out that lack of interest and depressed mood were not related to HbA1c. As shown in table 2 [2], depressed mood was a significant predictor for HbA1c in the overall sample and in individuals with Type 1 diabetes. We hope that our analysis and Kawada’s comments spur future longitudinal research that will further expand our understanding of the potential bidirectional relationship of depressive symptoms and glycaemic control in people with diabetes. We believe that the heterogenic nature of depression should not be overlooked here and may help to guide research and interventions for improving both mental health and glycaemic control in individuals with diabetes.
Funding sources
None.
Competing interests
None declared. M. Bot1, F. Pouwer2, P. de Jonge3 and F. Snoek4 Department of Psychiatry and the EMGO Institute for Health and Care Research, VU University Medical Centre, and GGZ inGeest, Amsterdam, 2Department of Medical and Clinical Psychology, Center of Research on Psychology in Somatic Diseases CoRPS, Tilburg University, Tilburg, 3Interdisciplinary Centre for Psychiatric Epidemiology, University Medical Centre Groningen, Groningen and 4Diabetes Psychology Research Group, Department of Medical Psychology, EMGO-Institute, VU University Medical Centre, Amsterdam, the Netherlands 1
References 1 Kawada T. Depressive symptoms and HbA1c in patients with Type 1 and Type 2 diabetes. Diabet Med 2014; 31: 759–760. 2 Bot M, Pouwer F, de Jonge P, Tack CJ, Geelhoed-Duijvestijn PHLM, Snoek FJ. Differential associations between depressive symptoms and glycaemic control in outpatients with diabetes. Diabet Med 2013; 30: e115–e122. 3 Lustman PJ, Anderson RJ, Freedland KE, de Groot M, Carney RM, Clouse RE. Depression and poor glycemic control: a meta-analytic review of the literature. Diabetes Care 2000; 23: 934–942. 4 Koren D. Levitt Katz LE, Brar PC, Gallagher PR, Berkowitz RI, Brooks LJ. Sleep architecture and glucose and insulin homeostasis in obese adolescents. Diabetes Care 2011; 34: 2442–2447. 5 Ayas NT, White DP, Manson JE, Stampfer MJ, Speizer FE, Malhotra A et al. A prospective study of sleep duration and
ª 2014 The Authors. Diabetic Medicine ª 2014 Diabetes UK
