Status of prevalence study on multimorbidity of chronic disease in China: systematic review

It is imperative to provide a more uniform method to improve the validity of prevalence studies on multimorbidity. However, the status of prevalence studies on multimorbidity of chronic disease is still yet to be confirmed in China. The objective of the present systematic review was to evaluate the variance across prevalence studies and to explore possible explanations for variations in China. Published literature was obtained from four databases. The studies that described the prevalence of multimorbidity on chronic disease based on the general population were considered. We assessed the risk of bias by a preplanned checklist referring to STROBE (Strengthening the Reporting of Observational Studies in Epidemiology). The heterogeneity among eligible studies was estimated by I(2) statistic and P-value using MetaAnalyst software. Nine studies were eligible for this systematic review. The prevalence of multimorbidity among the population aged 60 years or more ranged from 6.4% (95% CI 5.1-8.0) to 76.5% (95%CI 73.6-79.2). However, just two of nine studies could be judged as having a low risk of bias. It was shown that key items introducing the risk of bias included inconsistent sampling method, lacking of uniform measure indices and data source based on self-report. Heterogeneity test showed I(2)  = 50% (P < 0.001), which showed there was substantial variation among individual studies. Therefore, only a narrative summary rather than meta-analysis was carried out. Marked methodology heterogeneity exists among prevalence studies on multimorbidity. Suggested methodological aspects that should be considered in future studies include sampling method, measure indices of multimorbidity and data source.