Risk of mortality and complications in people with depressive disorder and diabetes mellitus: A 20-year population-based propensity score-matched cohort study
Matthew Tsz Ho Ho, Joe Kwun Nam Chan, Heidi Ka Ying Lo, Catherine Zhiqian Fang, Corine Sau Man Wong, Krystal Chi Kei Lee, Francisco Tsz Tsun Lai, Amy Pui Pui Ng, Ken Qingqi Chen, William Chi Wai Wong, Wing Chung Chang
Abstract
People with depression have increased premature mortality and elevated prevalence of diabetes-mellitus compared to general population. However, risk of mortality and diabetes-related complications among patients with depression and co-occurring diabetes is under-studied. This population-based propensity score-matched (1:10) cohort study identified 12,175 patients with pre-existing depression and incident-diabetes (depression-diabetes group) and 117,958 patients with incident-diabetes only (diabetes-only group) between 2002 and 2021 in Hong-Kong, using territory-wide medical-record database of public-healthcare services, to investigate whether depression increased the risk of overall mortality, complications and post-complication mortality in people with diabetes. Associations of depression with all-cause mortality, complication and post-complication all-cause mortality rates were examined by Cox proportional-hazards model. Complications were assessed by Diabetes-Complications-Severity-Index (DCSI). Associations of complications, in terms of DCSI scores (complication burden), specific types and two-way combinations of complications (complication patterns) with all-cause mortality rate in depression were also examined. Our results showed that depression-diabetes group exhibited increased all-cause mortality risk (adjusted hazards-ratio: 1.06 [95 %CI: 1.02-1.10]) relative to diabetes-only group, particularly among men and older age group, with significantly higher rate of experiencing neuropathy (1.44 [1.27-1.62]) and metabolic complications (1.30 [1.09-1.56]) and lower likelihood of peripheral-vascular complications, retinopathy and nephropathy, albeit comparable macrovascular and microvascular complication rates. The mortality-rate-ratio for patients with depression and diabetes was significantly higher than patients with diabetes-only at a low level of complication burden. In conclusion, depression patients with co-occurring diabetes are at increased risk of excess mortality. Further research is warranted to improve diabetes-related outcomes and reduce mortality gap in this vulnerable population.