Chae WR, Kohring C, Rohde C, Köhler-Forsberg O, Otte C, Holstiege J. Eight-year nationwide study of the bidirectional association between type 2 diabetes and depression in nearly 8 million German outpatients.
BMJ Open Diabetes Res Care 2024;
12:e003903. [PMID:
38719506 PMCID:
PMC11085903 DOI:
10.1136/bmjdrc-2023-003903]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 03/23/2024] [Indexed: 05/12/2024] Open
Abstract
INTRODUCTION
Research linking type 2 diabetes and depression mostly relied on hospital-based diagnoses or prescription data, overlooking many outpatient diagnoses. We aimed to quantify the risks of depression in individuals newly diagnosed with type 2 diabetes, and type 2 diabetes in those newly diagnosed with depression, while exploring potential risk differences depending on age, sex, and follow-up time.
RESEARCH DESIGN AND METHODS
We conducted a matched cohort study using German nationwide outpatient claims data from 2012 to 2022. Participants were individuals newly diagnosed with type 2 diabetes (N=294 642) or depression (N=1 271 537) in 2015, matched in a 1:4 ratio to controls without these conditions by age, sex, and region. The bidirectional risk was evaluated over an 8-year period using mixed-effects Cox proportional hazards models, adjusting for the Charlson Comorbidity Index, urbanicity, and area-level deprivation.
RESULTS
New type 2 diabetes diagnosis was associated with higher depression risk over 8 years (N=54 561 with depression, HR=1.23, 99% CI=1.21 to 1.24). Similarly, depression diagnosis was linked to an increased type 2 diabetes risk (N=71 848 with type 2 diabetes, HR=1.15, 99% CI=1.14 to 1.17). The association between depression and type 2 diabetes was stronger in younger age groups, especially under 34 years. Findings held across sex-stratified analyses. Time stratification showed a more pronounced association between type 2 diabetes and depression risk during the earlier follow-up quarters, whereas the risk of developing type 2 diabetes after depression diagnosis remained constant throughout the follow-up period.
CONCLUSIONS
Our findings confirm a bidirectional link between type 2 diabetes and depression, particularly in younger individuals. As type 2 diabetes and depression are frequent, future research needs to study whether preventive approaches can reduce the risk of developing this comorbidity.
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