title: Impact of medication adherence on renal function in comorbid patients with type 2 diabetes and depression: protocol for a cohort study.
abstract: BACKGROUND
  Prevention, or slowing the progression, of diabetic nephropathy is one of the important goals in diabetes care. Although the impact of depression is a concern in patients with diabetes, it is unknown whether there is an association between adherence to hypoglycemic medication and the decline of renal function in comorbid patients with diabetes and depression. We will conduct a cohort study aimed at examining (1) depression as a predictor of renal function decline, and (2) how adherence to hypoglycemic medication relates to depression and renal function decline in patients with type 2 diabetes.
  
  
  METHODS
  In this multicenter cohort study, 550 patients with type 2 diabetes aged 20 years and older will be recruited at 20 outpatient clinics in general medicine and psychiatry. We will measure depression (Patient Health Questionnaire), medication adherence (medication possession ratio, Morisky Medication Adherence Scale, and one-item hypoglycemic medication adherence scale), and renal function (urinary albumin-creatinine ratio and estimated glomerular filtration rate) at baseline and at the 12-month follow-up. The primary endpoint is decline of renal function at 12 months. The secondary endpoints include clinical variables, quality of life, and the attitude of professionals toward depression. We will perform multivariable linear regression analysis to evaluate the effects of medication adherence on the decline of renal function in comorbid patients with type 2 diabetes and depression.
  
  
  CONCLUSIONS
  To our knowledge, this will be the first study to examine how adherence to hypoglycemic medication relates to the decline of renal function in comorbid patients with type 2 diabetes and depression. The results of the study will have implications for practitioners of diabetes care, policy makers, and researchers for the prevention and treatment of diabetic nephropathy.
  
  
  BACKGROUND
  UMIN000017513 (Registered on May 22, 2015).
authors.affiliation: Department of Social Psychiatry, National Institute of Mental Health, National Center of Neurology and Psychiatry, Tokyo, Japan. ItoHiroto@ncnp.go.jp.
authors.forename: Hiroto
authors.initials: H
authors.lastname: Ito
authors.affiliation: Department of Biostatistics, Kyoto University School of Public Health, Kyoto, Japan.
authors.forename: Tosiya
authors.initials: T
authors.lastname: Sato
authors.affiliation: Division of Diabetic Research, Clinical Research Institute, National Hospital Organization Kyoto Medical Center, Kyoto, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Satoh-Asahara
authors.affiliation: Department of Diabetes and Metabolic Medicine, National Centre for Global Health and Medicine, Tokyo, Japan.
authors.forename: Mitsuhiko
authors.initials: M
authors.lastname: Noda
mesh_terms: D001291:Attitude of Health Personnel; D002985:Clinical Protocols; D015331:Cohort Studies; D003863:Depression / Q000150:complications*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000188:drug therapy* / Q000523:psychology; D003928:Diabetic Nephropathies / Q000453:epidemiology / Q000209:etiology*; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D055118:Medication Adherence; D011788:Quality of Life
chemical_list: D007004:Hypoglycemic Agents