Patients with major depressive disorder (MDD), particularly those ≥65 years of age, have a higher incidence rate of Alzheimer dementia (AD) and non-AD (NAD) compared with people without MDD, according to a recent study published in Aging and Mental Health.

Chun-Jen Huang, MD, PhD, MPH, from the department of psychiatry, Kaohsiung Medical University Hospital, Taiwan, and colleagues analyzed claims data from Taiwan’s National Health Insurance Research Database. Researchers extracted data of patients with MDD (n=13,067) and patients without MDD (n=52,268). Patients were matched by index date, age, sex, geographical area, monthly income, and selected comorbidities. Only patients who had ≥2 outpatient service claims or 1 inpatient service claim of dementia were included. The incidence of dementia, classified as AD and NAD, among the 2 groups comprised the primary outcome of interest.

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Patients with MDD had significantly higher incidence rates of AD (2.6% vs 0.6%; adjusted subdistribution hazard ratio [aSHR], 4.73; 95% CI, 4.05-5.52) compared with those without MDD. In addition, a higher proportion of patients with MDD developed NAD compared with patients without MDD (0.59% vs 0.15%; aSHR, 3.69; 95% CI, 2.68-5.08).

Patients ≥65 years of age had higher incidence rates of AD and non-AD compared with younger patients aged ≤50 years (289.27 vs 3.33 and 47.51 vs 1.80 per 10,000 person-years, respectively). In addition, older age, MDD, coronary artery disease, stroke, and high Charlson Comorbidity Index score were linked to elevated risk for AD, whereas hypertension, stroke, MDD, and older age were associated with risk for NAD.

Limitations of the study included the subdivision of patients into only 3 age categories, the reliance on health insurance administrative database claims, and the lack of assessment of medication prescriptions for depression. The study investigators wrote that additional research may be necessary “to clarify the underlying pathophysiology of the association between MDD and dementia and investigate whether prompt intervention may reduce this risk.”

Reference

Huang CJ, Weng SF, Wang JJ, Hsieh HM. Competing risk analysis of the association between dementia and major depressive disorder: a nationwide population-based study in Taiwan [published online February 3, 2020]. Aging Ment Health. doi:10.1080/13607863.2020.1720598