Purpose : Diabetes patients with depression generally have worse diabetes care than those without depression, but mechanisms that account for this are not fully elucidated. Here we test the hypothesis that diabetes patients with a depression diagnosis have lower rates of glycated hemoglobin (A1c) and LDL-cholesterol monitoring.
Methods : Among 14,144 adults with diabetes receiving care at a large multispecialty medical group in Minnesota, 2,179 were classified as having a depression diagnosis based on having either (a) two or more depression ICD-9 codes, or (b) one depression ICD-9 code plus at least one prescription fill for depression medication in a one-year period of time. Subjects were tracked for four years. Data on A1c and lipid tests were extracted from claims data, and verified by chart audit in a sub-sample of patients.
Results : The 2,179 subjects with a depression diagnosis had mean age 60 years, 8.2 primary care visits per year, 38% were male, 86% took an antidepressant, and 12% had newly diagnosed diabetes. Relative to those without a depression diagnosis, significantly fewer of those with a depression diagnosis had recommended frequencies of A1c and LDL tests in bivariate analysis (35% compared with 30%, p<.001). This finding persisted after adjustment in multivariate models for age, sex, co-morbidity, number of primary care visits, and incident diagnosis of diabetes.
Conclusion : Having a depression diagnosis is associated with less frequent A1c and LDL monitoring in diabetes patients. Lower frequency of monitoring may contribute to the worse diabetes care in depressed patients. Strategies to increase monitoring, such as point of care A1c and direct LDL measurement may lead to better diabetes care. The data also suggest that diabetes care accountability measures may need to be adjusted for differences in depression occurrence across providers, clinics, or medical groups.