Association Between Specific Depression Symptoms and Glycemic Control Among Patients With Comorbid Type 2 Diabetes and Provisional Depression

Objective: To determine whether specific depression symptoms are associated with glycemic control independent of potential demographic and clinical covariates among primary care patients with comorbid type 2 diabetes and provisional threshold or subthreshold depression.

Method: We examined a convenience sample of patients diagnosed with type 2 diabetes and provisional threshold or subthreshold depression (N = 82) at 2 family health centers. Cases were identified using a population-based registry of patients diagnosed with type 2 diabetes (ICD-9 codes 250.00 for controlled type 2 diabetes and 250.02 for uncontrolled type 2 diabetes). Data from patients with a primary care provider appointment from the beginning of April 2011 through the end of June 2012 and with at least one 9-item Patient Health Questionnaire (PHQ-9) depression screener and a glycated hemoglobin A1c (HbA1c) laboratory test between 2 weeks before and 10 weeks after PHQ-9 screening were eligible for inclusion. We defined provisional threshold or subthreshold depression using PHQ-9 scoring criteria, which were designed to yield provisional diagnostic information about major depressive disorder based on DSM-5 diagnostic criteria.

Results: Patients reporting higher severity of sleep problems on the PHQ-9 had significantly higher HbA1c levels (mean = 8.48, SD = 2.17) compared to patients reporting lower severity or absence of this symptom (mean = 7.19, SD = 1.34, t48.88 = −3.13, P = .003). Problems with sleep contributed unique variance on glycemic control (β = 0.27, P = .02) when controlling for potential clinical and demographic covariates, with those reporting more sleep difficulties having higher HbA1c levels.

Conclusions: For patients with type 2 diabetes and provisional threshold or subthreshold depression, it may be prudent to aggressively address sleep problems as a potential mechanism toward improving diabetes control.