Background: This longitudinal study of patients with diabetes examined the relationship between changes in depressive symptoms and changes in diabetes self-care behaviors over 5 years.
Design, patients and measurements: A total of 2759 patients with diabetes enrolled in a large HMO were followed over a 5-year period. Patients filled out a baseline mail survey and participated in a telephone interview 5 years later. Depression was measured with the Patient Health Questionnaire (PHQ-9) and diabetes self-care was measured with the Summary of Diabetes Self-Care Activities (SDSCA) questionnaire. Baseline and longitudinal evidence of diabetes and medical disease severity and complications were measured using ICD-9 and CPT codes and verified by chart review.
Results: At the 5-year follow-up, patients with diabetes with either persistent or worsening depressive symptoms compared to those in the no depression group had significantly fewer days per week of following a healthy diet or participating in > or = 30 min of exercise. At 5-year follow-up, patients with clinical improvement in depression symptoms showed no differences compared to the no depression group on number of days per week of adherence to diet but showed deterioration in adherence to exercise on some, but not all, measures.
Conclusions: Patients with diabetes with persistent or worsening depressive symptoms over 5 years had significantly worse adherence to dietary and exercise regimens than patients in the no depression group. These results emphasize the need to further develop and test interventions to improve both quality of care for depression and self-care in diabetes patients.