Prevalence of Anxiety in Patients with Mild Cognitive Impairment: A Systematic Review and Meta-analysis

Background: Prevalence rates of anxiety in patients with mild cognitive impairment (MCI) varied widely across studies and may confer a higher likelihood of progression to dementia. Our aim was to estimate the prevalence of anxiety in MCI and identify reasons for heterogeneity in the reported results.

Methods: A computerized search in PubMed, EMBASE, and Psyc INFO for studies on anxiety in MCI was performed up to March 2017. The overall prevalence of anxiety in patients with MCI was pooled using a random-effects model. Heterogeneity was explored using stratification (recruitment resource; method of anxiety diagnosis; method of MCI diagnosis; and region) and random-effects meta-regression.

Results: Of 2494 unique abstracts, 290 were selected for full-text review, and 39 studies, representing 10,587 patients, met all inclusion criteria. The overall pooled prevalence of depression in patients with MCI was 21.0% (95% CI, 16.2-26.7) with significant heterogeneity present (I = 97.2%, p < 0.001). When stratified by source, the prevalence of anxiety in patients with MCI in community-based samples was 14.3% (95% CI, 9.7-20.5) and was 31.2% (95% CI, 23.6-40.0) in clinic-based samples, which was significantly different (p < 0.01). The prevalence of anxiety estimates also differed significantly, when stratification by the method of anxiety diagnosis (p < 0.01). However, the criteria used for MCI diagnosis and geographical region did not significantly influence the prevalence estimate.

Limitations: We did not consider the usage of anti-anxiety drugs and language bias.

Conclusions: The prevalence of anxiety in patients with MCI was common and variability in prevalence of anxiety across studies can be attributed partly to the source of the sample and method of anxiety diagnosis. Further research is needed to identify sources of heterogeneity.