Association between serum creatine kinase levels and the risk of all-cause mortality among centenarians: A prospective cohort study in China

Background Muscle mass (MM) was important because of its strong correlation with all-cause mortality. However, its assessment was complex, nonportable and expensive. Serum creatine kinase (CK) was proposed to counteract this problem. However, its correlation with all-cause mortality was unknown. Objectives The aim of this study was to investigate the associations between serum CK levels and all-cause mortality risk in Chinese centenarians. Methods A prospective cohort study of centenarians was conducted to classify serum CK levels according to all-cause mortality via restricted cubic spline (RCS) analysis, Cox regression analysis and Kaplan‒Meier analysis. Results We included 949 participants with a median follow-up of 29.4 months (interquartile range (IQR) 14.5, 51.7). A total of 92.9% of the subjects died. The RCS analysis revealed an inverse J-shaped relationship between the serum CK level and the risk of death. The mortality rate of centenarians with serum CK levels ranging from 8–66 U/L (Q1–Q2) was 34.3% higher than that of those with serum CK levels ranging from 66–192 U/L (Q3–Q4) (multivariable analysis hazard ratio (HR), 1.343; 95% confidence interval (CI), 1.173–1.538; P  < 0.001). Kaplan–Meier analyses revealed that centenarians with lower serum CK levels had significantly shorter median survival time (Q1‒Q2 versus Q3‒Q4: 26 months versus 36 months, log-rank P  < 0.001). Conclusions Serum CK levels were negatively associated with centenarian mortality, indicating that they may predict mortality risk in centenarians. CK could be utilized as an independent predictor of mortality in centenarians. Clinical Trial Registry number and website where it was obtained. Not applicable. Registry and registry number for systematic reviews or meta-analyses. Not applicable.