van Dalen JW, et al. - How apathy is associated with incident dementia in dementia-free older individuals was assessed via systematic review and meta-analysis of 16 studies including 7,365 patients. Memory clinic patients had a roughly 2-fold increased risk of dementia in association with apathy. Researchers suggest regarding apathy as a relevant, cheap, noninvasive, and easily measurable marker of increased risk of incident dementia, especially since these patients are vulnerable and may go without health care.

Methods

• A systematic search of Medline, Embase, and PsychINFO databases was done by two reviewers.
• Researchers included prospective cohort studies in general populations or memory clinic patients without dementia, using clear definitions of apathy and dementia, and reporting on the association between apathy and incident dementia.
• Pooled crude risk ratios, maximally adjusted reported hazard ratios (HR), and odds ratios (OR) using DerSimonian-Laird random effects models were the main outcomes assessed.

Results

• The study populations had median age of 71.6 years (mean age ranged from 69.2 to 81.9 years); 35% to 70% (median, 53%) of the populations comprised women.
• In this work, 7,299 participants had available apathy status.
• Populations with subjective cognitive concerns (n=2), mild cognitive impairment (n=11), cognitive impairment no dementia (n=1), or mixed cognitive and no cognitive impairment (n=2) were included in the studies.
• As per findings, 1,470 of 7,299 participants (20.1%) had apathy.
• For 1.2 to 5.4 years, follow-up was performed.
• The combined risk ratio of dementia for patients with apathy was 1.81 (95% CI, 1.32-2.50; I2=76%; n=12), the hazard ratio was 2.39 (95% CI, 1.27-4.51; I2=90%; n=7), and the odds ratio was 17.14 (95% CI, 1.91-154.0; I2=60%; n=2) in studies using validated apathy definitions (n=12).
• The association between apathy and dementia weakened with increasing follow-up time, age, and cognitive impairment in accordance to subgroup analyses, meta-regression, and individual study.
• Ninety-five percent of heterogeneity in mild cognitive impairment could be explained via meta-regression adjusting for apathy definition and follow-up time.