Longitudinal effects of modified creatinine index on all-cause mortality in individuals receiving hemodialysis treatment

BACKGROUND: The modified creatinine index (mCI), as a surrogate marker of muscle mass, has been associated with poor outcomes in patients undergoing hemodialysis. However, a single assessment may not reflect the clinical significance before an adverse clinical endpoint. OBJECTIVE: Analyze mCI trajectories and their association with all-cause mortality in incident hemodialysis patients. DESIGN: Retrospective observational cohort. SETTING: Outpatient dialysis facility. PATIENTS AND METHODS: We followed a cohort of patients who underwent maintenance hemodialysis treatment at least three times weekly for at least three months from 19 June 2010 to 29 December 2017. Clinical and laboratory features were measured at baseline. Longitudinal changes in the mCI were modeled using a joint longitudinal and survival model adjusted for baseline covariates and body mass index trajectories. MAIN OUTCOME MEASURE: All-cause mortality. SAMPLE SIZE: 408 with 208 males (50.7%). RESULTS: The mean (SD) age was 62.2 (12.3) years. The mCI changes were evaluated for a median (interquartile range) follow-up of 2.16 (1.13, 3.73) years. Forty-six percent (n=188) of patients reached the endpoint. A steeper slope (per 0.1 unit increase in the decrease rate) in modified creatinine index was associated with increased risk of all-cause mortality (HR, 1.04; 95% CI, 1.02–1.07; P=.011). In addition, an annual 1 mg/kg/day decrease in modified creatinine index level increased the hazard of all-cause mortality by 4% (HR, 1.04; 95% CI, 1.02–1.07; P=.001). LIMITATIONS: Residual kidney function was not observed in the data. Setting was single center and thus results may not be generalizable to other populations. CONCLUSION: All-cause death was significantly associated with loss of muscle mass over time. Longitudinal trajectories of nutritional markers may predict the clinical outcomes in patients undergoing hemodialysis. This may also be valuable for individual risk stratification. Furthermore, early management may provide an opportunity to improve patient survival. CONFLICT OF INTEREST: None.