The prevalence and progression of mild cognitive impairment among clinic and community populations: a systematic review and meta-analysis.

BACKGROUND

It has been reported that up to 42% of the population aged over 60 are affected by mild cognitive impairment (MCI) worldwide. This study aims to investigate the prevalence and progression of MCI through a meta-analysis.

METHODS

We searched Embase and PubMed for relevant literature. Stable disease rate (SR), reversion rate (RR), dementia rate (DR), and Alzheimer's disease rate (AR) were used to evaluate the progression of MCI. The prevalence and progression rates were both obtained by reported percentile and indirect data analysis. Additionally, we carried out sensitivity analysis of each index by excluding some studies due to influence analysis with the most publication bias.

RESULTS

Effect size (ES) was used to present adjusted overall prevalence (16%) and progression rates including SR (45%), RR (15%), DR (34%), and AR (28%) of MCI. Compared with clinic-based outcomes, MCI prevalence, SR, and RR are significantly higher in community, while DR and AR are lower. Despite significant heterogeneity found among the studies, no publication bias was observed.

CONCLUSIONS

Age and gender were observed to be associated with MCI, in which age was considered as an impact factor for DR. The strong heterogeneity may result from variations in study design and baselines. Standardized MCI criteria were suggested to systematically evaluate MCI in the future.