Mortality risk of chronic kidney disease: A comparison between the adult populations in urban China and the United States

Background Chronic kidney disease (CKD) is a risk factor for all-cause mortality in the United States, but the evidence from China is limited. We investigate whether prognosis of CKD (mortality) differs between the two countries. In particular, we sought to compare the strength of association between CKD stage and all-cause mortality, by country. Methods Mortality-linked data from China National Survey of Chronic Kidney Disease (urban population, n = 25,269) and US NHANES (2005-2010, n = 15,209) for adults >20 years old were analyzed. The Chinese cohort was followed until Dec 31, 2013, while the NHANES cohort until Dec 31, 2011. CKD was defined by eGFR <60ml/min/1.73m(2) or albuminuria (defined as ACR >= 30mg/g). Weighted Cox models were used to evaluate the association between the two CKD indicators and mortality. Both stratified and combined models (with country interactions) were explored. Results The Chinese sample had a lower proportion of eGFR<60 ml/min/1.73m(2) (3.7% vs. 6.9%) and albuminuria (7.6% vs. 9.0%), compared to the US. Higher rates of mortality were observed with higher stages of CKD in both countries. HRs for mortality in the more advanced CKD categories reached 2.18 (1.14-4.15) in China and 1.66 (1.18-2.32) in the US in the absence of albuminuria, and 2.30 (1.13-4.68) and 3.04 (2.33-3.96) in the presence of albuminuria. No significant interactions were detected between country and these categories. Conclusion The association between albuminuria and reduced eGFR and all-cause mortality was similar in both countries, with albuminuria being associated with the larger effect size compared to lower eGFR.