Diabetes prevalence, diabetes regimen and co-morbidity in depressed patients compared with non-depressed patients in primary care in the Netherlands

Aims To assess the prevalence of diabetes in depressed patients compared with non-depressed matched controls and to compare diabetes regimen and co-morbidity in depressed patients with diabetes vs. non-depressed patients with diabetes in primary care in the Netherlands. Methods A retrospective case-control study over 3 years (2002-2004). Data for depressed patients (n = 7128) and non-depressed matched controls (n = 23772) were available from an electronic medical record system of 20 general practices organized in one large primary care organization in the Netherlands. Matching was based on year and month of birth, sex and general practitioner. Diabetes, diabetes regimen (i.e. oral glucose medication, insulin or both) and co-morbidity were defined using Anatomical Therapeutic Chemical classification codes of delivered medication. Results The prevalence of diabetes was 5.5% (n = 393) among depressed patients, which was 2.6 times higher than in non-depressed matched controls where the figure was 2.1%(n = 494; P < 0.001). Diabetes regimen, i.e. the proportions of subjects on oral glucose medication, insulin or both did not differ among depressed patients with diabetes (51, 27 and 22%, respectively) compared with non-depressed patients with diabetes (51, 30, 19%; P = 0.53). Co-morbidity was significantly more prevalent among depressed patient with diabetes than in non-depressed patients with diabetes. Conclusions Compared with non-depressed matched controls, adults with treated depression have almost three times higher rates of diabetes. Depressed patients with diabetes had more co-morbidities compared with non-depressed patients with diabetes, whereas diabetes regimen did not differ.