Depression as a prognostic factor for conversion from mild cognitive impairment to all-cause dementia and Alzheimer's disease: a systematic review and meta-analysis of longitudinal studies
Abstract
Background: Mild cognitive impairment (MCI) is a transitional stage between normal aging and dementia, with annual conversion rates to Alzheimer's disease (AD) or all-cause dementia estimated at 10%-15%. The role of depression as a prognostic factor for dementia progression remains unclear. This systematic review and meta-analysis aimed to clarify the association between depression and risk of conversion from MCI to AD and all-cause dementia.
Methods: We conducted a systematic review and meta-analysis of longitudinal cohort studies following PRISMA 2020 guidelines. PubMed, PsycINFO, Web of Science, and Scopus were searched. Eligible studies included adults with MCI, depression assessed by clinical diagnosis or validated scales, and reported hazard ratios (HRs) for progression to dementia. Random-effects meta-analyses were performed for unadjusted and adjusted HRs. Risk of bias was assessed using the Newcastle-Ottawa Scale, and certainty of evidence was evaluated with GRADE.
Results: Seventeen studies were included, with follow-up ranging from 6 months to 12 years. In unadjusted analyses, baseline depression was associated with increased risk of progression overall (HR 1.66, 95% CI 1.22-2.26); however, heterogeneity across studies was high (I 2 = 99.1%), limiting confidence in the pooled estimate. The association was significant for progression to AD (HR 1.57, 95% CI 1.15-2.15; I 2 = 99.4%), but not for all-cause dementia (HR 1.95, 95% CI 0.85-4.48; I 2 = 90%). In adjusted…
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Evidence Hub reads this as a meta-analysis, done in people. Its evidence level is 1 of 5 (Highest · pooled evidence). Pooled evidence from several studies sits at the top of the evidence pyramid.
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