Risk of suicide in association with major depressive disorder among patients with dementia: a population-based nested case-control study

Abstract

Objective: This study aimed to explore the association between major depressive disorder (MDD) and suicide risk in patients with dementia. Methods: A cohort of 625,218 individuals aged X 40 years with dementia was identified from Taiwan’s National Health Insurance Research Database (NHIRD) between 2007 and 2018. After excluding prevalent cases in 2007, a nested case-control study enrolling 1,256 suicide cases and 5,022 matched controls was conducted. The frequencies of MDD-related outpatient or inpatient visits over a 7-year period preceding the event dates were calculated and analyzed for association using conditional logistic regression. Results: Dementia comorbid with MDD was associated with increased suicide risk (adjusted OR [AOR]: 2.67), particularly in individuals with p 1.0 MDD episodes per year (AOR: 2.85). A similar association was observed only in individuals aged X 65 years and males, with a pronounced risk of suicide in those experiencing p 1.0 MDD episodes per year (AOR: 3.08 for individuals aged X 65 years; AOR: 3.28 for males). Conversely, the risk increase was evident with 4 1.0 MDD episodes per year in those aged o 65 years (AOR: 3.04) and females (AOR: 2.45). Conclusion: MDD is associated with suicide risk in patients with dementia. The strength of this association possibly varies with age and gender.