Depressive symptoms, co-morbidities, and glycemic control in Hong Kong Chinese elderly patients with type 2 diabetes mellitus

Background and objectives: Undiagnosed depression is an important comorbidity in type 2 diabetes (T2D) which can be detected using the Geriatric Depression Scale (GDS-15) questionnaire. In this cross-sectional study, we examined the associations of depression using GDS score with control of cardiometabolic risk factors and health status in elderly patients with T2D. Setting and participants: Between February and December 2013, patients aged ≥ 65 years who underwent structured comprehensive assessment as a quality improvement program at the Diabetes Center of a teaching hospital were invited to complete the GDS-15 questionnaire. Main outcome measures: Depression was defined as a GDS score ≥ 7. Demographic data, prior history of co-morbidities, frequency of self-reported hypoglycemia, and attainment of treatment targets defined as HbA_1c, < 7%, blood pressure < 130/80 mmHg, and LDL-C < 2.6 mmol/L were documented. Results: Among 325 participants (65% male, median [interquartile range] age: 69 [8] years), 42 (13%) had depression. Patients with depression had longer disease durations (mean ± SD: 15.1 ± 9.1 vs. 11.6 ± 8.1 years, P = 0.02), more frequent self-reported hypoglycemic events (17 vs. 6%, P = 0.03) and were less likely to attain all three treatment targets (0 vs. 16%, P = 0.004) than those without depression. On multivariable analysis, patients with depression had an odds ratio of 2.84 (95% confidence intervals: 1.35-6.00, P = 0.006) of reporting prior history of co-morbidities. Conclusion: In elderly patients with T2D, depression was not uncommon especially in those with poor control of risk factors, hypoglycemia, and co-morbidities. Inclusion of GDS-15 questionnaire during structured assessment for complications and risk factors can identify these high-risk patients for more holistic management of their physical and mental health.