Effect of depression on mortality in type 2 diabetes mellitus after 8 years of follow-up. The DIADEMA study

Abstract

Aim: To assess the effect of depression on all-cause mortality in patients with type 2 diabetes mellitus (T2DM) followed up during 8 years in primary care in Spain.

Methods: Depression was diagnosed according to MINI 5.0.0 questionnaire, physician-diagnosis or following antidepressant therapy for at least two months in 3923 people with T2DM. We analyzed mortality-rates/10,000 person-years. We compared survival according to baseline depression with Kaplan-Meier estimates and the log-rank test. We performed Cox proportional hazard model analyses.

Results: Baseline depression was diagnosed in 22.1% of participants. Mortality was higher in patients with depression (31.9% vs. 26.9%; p = 0.003), who had a significantly poorer survival (median survival = 7.4 vs. 7.8 years, respectively; Log Rank = 15.83; p < 0.001). Depression showed an adjusted mortality hazard ratio (HR) = 1.40 (95%CI:1.20-1.65; p < 0.001). The strongest predictive factors were: age >75 years (HR = 6.04; 95%CI:4.62-7.91; p < 0.001), insulin use (HR = 2.37; 95%CI:1.86-3.00; p < 0.001), lower limb amputation (HR = 1.99; 95%CI:1.28-3.11; p = 0.002), heart failure (HR = 1.94; 95%CI:1.63-2.30; p < 0.001), and male gender (HR = 1.90; 95%CI:1.59-2.27).

Conclusion: In a Spanish cohort of older T2DM patients, depression was associated with a higher mortality risk. More efforts are needed to minimize the influence of depression on mortality in people with T2DM and to implement measures that allow its early diagnosis and effective treatment.

Keywords: Depression; Diabetes; Mortality.