Diabetes in primary care: prospective associations between depression, nonadherence and glycemic control.
BACKGROUND
Findings are inconsistent regarding the degree to which depression may exert a negative impact on glycemic control in patients with type 2 diabetes. We therefore aimed to examine the longitudinal relationship between depression, behavioral factors, and glycemic control.


METHODS
In a prospective component of a nationally representative sample, 866 patients with type 2 diabetes aged >or=18 years completed a standardized assessment including a laboratory screening, questionnaires, and diagnostic measures. Subsequent to baseline (t(0)), patients were tracked over a period of 12 months (t(1)). Depression was assessed according to DSM-IV and ICD-10 criteria. Glycemic control was determined by levels of glycosylated hemoglobin (HbA(1c)); a level of >or=7% was judged as unsatisfactory. Regression analyses were performed to analyze the prospective relationship between depression, medication adherence, diabetes-related health behavior, and HbA(1c).


RESULTS
Patients with depression at t(0) revealed increased rates of medication nonadherence (adjusted OR: 2.67; CI: 1.38-5.15) at t(1). Depression (adjusted regression coefficient: beta = 0.96; p = 0.001) and subthreshold depression (beta = 1.01; p < 0.001) at t(0) also predicted increased problems with diabetes-related health behavior at t(1). Adjusted ORs for poor glycemic control (HbA(1c) >or=7%) at t(1) were also increased for patients with baseline depression (2.01; CI: 1.10-3.69). However, problems with medication adherence as well as problems with diabetes-related health behavior at t(0) did not predict poor glycemic control at t(1).


CONCLUSIONS
In a prospective representative study of patients with type 2 diabetes, baseline depression predicted problems with medication adherence, problems with health-related behaviors, and unsatisfactory glycemic control at follow-up.
Dirmaier
Jörg
J
Department of Medical Psychology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. dirmaier@uke.uni-hamburg.de
Watzke
Birgit
B
Koch
Uwe
U
Schulz
Holger
H
Lehnert
Hendrik
H
Pieper
Lars
L
Wittchen
Hans-Ulrich
HU
D000368:Aged; D003866:Depressive Disorder / Q000097:blood* / Q000175:diagnosis / Q000523:psychology*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000188:drug therapy / Q000523:psychology*; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism*; D015438:Health Behavior; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage*; D008019:Life Style; D008137:Longitudinal Studies; D008297:Male; D055118:Medication Adherence / Q000523:psychology*; D008875:Middle Aged; D010555:Personality Inventory; D011320:Primary Health Care; D011446:Prospective Studies
D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; C517652:hemoglobin A1c protein, human