Utility of a Modified Controlling Nutritional Status Score in Mortality Risk Assessment of Patients on Hemodialysis

Purpose: Malnutrition is common among hemodialysis patients. A nutritional index may be important for their prognosis prediction. We examined the use of a modified version of the Controlling Nutritional Status (CONUT) score as a predictor of mortality in hemodialysis patients and investigated whether statin use modified the association.

Methods: We conducted a retrospective cohort study in 1130 adults (mean age 67.7 years, 35.0% women) on maintenance hemodialysis at four outpatient dialysis clinics in Japan. The exposure of interest was modified CONUT scores calculated by one-time data of serum albumin and total cholesterol at baseline, or mean data of these measures using multiple blood test results. The primary outcome was all-cause mortality. We examined the association between modified CONUT groups (low-risk, middle-risk, and high-risk) and mortality using multivariate Cox proportional hazard regression and logistic regression models in overall patients and by statin use.

Results: During a median follow-up of 6.6 years, 525 (46.5%) patients died. Analysis using both one-time and mean data showed increased mortality risk in the high-risk modified CONUT score group as compared to the low-risk group (mean data: HR 2.52, 95% CI 1.96, 3.24); when stratified by statin use, the effect appeared stronger among users (mean data: HR 5.84, 95% CI 2.98, 11.44). Strong predictive ability was observed, particularly for mortality risk at 5 year follow-up using mean data (AUC = 0.842).

Conclusion: Our results suggest that the modified CONUT score may be useful in helping clinicians quickly identify hemodialysis patients with poorer prognosis who may benefit from close monitoring and interventions.