Depression in patients with type 2 diabetes: impact on adherence to oral hypoglycemic agents.
BACKGROUND
Adherence to oral hypoglycemic agents (OHAs) is important for adequate glycemic control and prevention of future complications in patients with type 2 diabetes.


OBJECTIVE
To examine the impact of depression on adherence to OHAs in patients newly diagnosed with type 2 diabetes.


METHODS
Patients newly diagnosed with type 2 diabetes during a 4 year period were identified from a Medicaid claims database. Presence of preexisting depression was determined on the basis of ICD-9-CM codes. Adherence to OHAs was computed using prescription refill data for a 12 month follow-up period from the date of the index OHA prescription. Two separate adherence indices (Medication Possession Ratio-1 [MPR-1], Medication Possession Ratio-2 [MPR-2]) were computed. The impact of depression on adherence was assessed after controlling for confounders such as demographics, comorbidity, provider interaction, complexity of regimen, and diabetes severity.


RESULTS
A total of 1326 newly diagnosed patients with type 2 diabetes were identified (depressed = 471; nondepressed = 855). Results of the study indicated that patients with depression had significantly lower adherence (MPR-1 86%; MPR-2 66%) to OHAs compared with patients without depression (MPR-1 89%; MPR-2 73%). Multivariate results indicated that depression was a significant predictor of adherence, with depressed patients being 3-6% less adherent to OHAs than nondepressed patients, after controlling for confounding factors.


CONCLUSIONS
Depression significantly impacts adherence to OHAs in patients with type 2 diabetes. The study results imply that depression screening and treatment need to be included in the protocol for management of patients with type 2 diabetes.
Department of Pharmacy Practice, College of Pharmacy and Health Sciences, Butler University, Indianapolis, IN 46208, USA. ikalseka@butler.edu
Iftekhar D
ID
Kalsekar
Suresh S
SS
Madhavan
Mayur M
MM
Amonkar
Eugene H
EH
Makela
Virginia G
VG
Scott
Stratford M
SM
Douglas
Betsy L Meredith
BL
Elswick
D000284:Administration, Oral; D015331:Cohort Studies; D003863:Depression / Q000517:prevention & control* / Q000523:psychology; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy / Q000523:psychology*; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance / Q000523:psychology; D012044:Regression Analysis; D012189:Retrospective Studies
D007004:Hypoglycemic Agents