To examine the relationship among patient-reported diabetes symptoms, severity of depressive illness and objective measures of diabetes control and severity among a population-based sample of patients with diabetes.

A mailed survey was sent to all patients with diabetes from nine primary care clinics of a Health Maintenance Organization. The Patient Health Questionnaire (PHQ-9) was used to diagnose major depression, the Self-Completion Patient Outcome instrument assessed diabetes symptoms and automated medical record data were used to measure diabetes treatment intensity, HbA_1c levels, diabetes complications and medical comorbidity. Analysis of covariance (ANCOVA) was used to determine if the number of diabetes symptoms was related to having major depression and to number of depressive symptoms. Logistic regression analyses determined the relative strengths of the associations between each individual diabetic symptom and presence of major depression, HbA_1c levels above 8.0% and two or more diabetes complications.

Among 4168 patients with diabetes, those with major depression (N=487) reported significantly more diabetes symptoms (mean=4.40) than participants without depression (mean=2.46) after adjusting for demographic characteristics, objective measures of diabetes severity and medical comorbidity [F(1,4029)=339.31, P<.0001]. The overall number of diabetes symptoms was related to the number of depressive symptoms (from 0 to 9) endorsed by participants [F(9,4021)=110.05, P<.0001]. Logistic regression analyses found that depression was significantly related to each of the 10 diabetes symptoms (all P<.001).

The depression-diabetes symptom association is stronger than the association of diabetes symptoms with measures of glycemic control and diabetes complications.