Cardiovascular Diseases and Risk-Factor Burden in Urban and Rural Communities in High-, Middle-, and Low-Income Regions of China: A Large Community-Based Epidemiological Study.

BACKGROUND: Most cardiovascular diseases occur in low- and middle-income regions of the world, but the socioeconomic distribution within China remains unclear. Our study aims to investigate whether the prevalence of cardiovascular diseases differs among high-, middle-, and low-income regions of China and to explore the reasons for the disparities.

METHODS AND RESULTS: We enrolled 46 285 individuals from 115 urban and rural communities in 12 provinces across China between 2005 and 2009. We recorded their medical histories of cardiovascular diseases and calculated the INTERHEART Risk Score for the assessment of cardiovascular risk-factor burden, with higher scores indicating greater burden. The mean INTERHEART Risk Score was higher in high- and middle-income regions than in low-income regions (9.47, 9.48, and 8.58, respectively, P<0.0001). By contrast, the prevalence of total cardiovascular disease (stroke, ischemic heart disease, and other heart diseases that led to hospitalization) was lower in high- and middle-income regions than in low-income regions (7.46%, 7.42%, and 8.36%, respectively, Ptrend =0.0064). In high- and middle-income regions, urban communities have higher INTERHEART Risk Score and higher prevalent rate than rural communities. In low-income regions, however, the prevalence of total cardiovascular disease was similar between urban and rural areas despite the significantly higher INTERHEART Risk Score for urban settings.

CONCLUSIONS: We detected an inverse trend between risk-factor burden and cardiovascular disease prevalence in urban and rural communities in high-, middle-, and low-income regions of China. Such asymmetry may be attributed to the interregional differences in residents' awareness, quality of healthcare, and availability and affordability of medical services.