Modified creatinine index and risk for cardiovascular events and all-cause mortality in patients undergoing hemodialysis: The Q-Cohort study

Background and aims: The modified creatinine (Cr) index, calculated by age, sex, pre-dialysis serum Cr levels, and Kt/V for urea, reflects skeletal muscle mass in patients on hemodialysis. Whether the modified Cr index is associated with cardiovascular events and all-cause mortality remains unknown. Methods: A total of 3027 patients registered in the Q-Cohort Study, a multicenter, prospective study of patients on hemodialysis in Japan, were analyzed. The main outcomes were cardiovascular events and all-cause mortality. Associations between sex-specific quartiles of the modified Cr index and outcomes were analyzed by the Cox proportional hazard models and the Fine–Gray proportional subdistribution hazards model. Results: The modified Cr index was correlated with known nutritional and inflammatory markers. During a 4-year follow-up, 499 patients died of any cause, 372 experienced heart disease, and 194 developed stroke. The risk for all-cause mortality was significantly higher in the lower quartiles (Q1 and Q2) than in the highest quartile (Q4) as the reference group (hazard ratios and 95% confidence intervals: Q1, 2.65 [1.69–4.25], Q2, 1.92 [1.27–2.94], and Q3, 1.31 [0.87–2.02]). The risk of heart disease was significantly higher in Q1 than in Q4 (hazard ratios and 95% confidence intervals: Q1, 1.64 [1.04–2.61], Q2, 1.34 [0.91–2.00], and Q3, 1.04 [0.71–1.52]). The risk of stroke was not associated with the modified Cr index. Conclusions: A lower modified Cr index is associated with an increased risk for heart disease and all-cause mortality, but not with the risk for stroke in patients on hemodialysis.