Prognostic Value of Controlling Nutritional Status Score and Prognostic Nutritional Index for All-Cause Mortality in Patients with Chronic Kidney Disease: The Fukuoka Kidney Disease Registry Study.

BACKGROUND

The controlling nutritional status (CONUT) score and prognostic nutritional index (PNI) are objective and convenient screening tools for the early detection of poor immune/nutritional status. Previous studies have shown that these indices are predictors of all-cause mortality in patients with chronic kidney disease (CKD). However, their prognostic value for mortality associated with factors beyond conventional cardiovascular (CV) risk factors has not been evaluated.

OBJECTIVES

This study aims to determine whether the addition of the CONUT score and PNI to conventional CV risk factors improves the prediction of all-cause mortality in a prospective cohort of patients with CKD.

METHODS

We studied 2773 patients with CKD who were not undergoing dialysis. The patients were allocated to groups according to their CONUT score (low, mild, or moderate-to-high) and tertiles of PNI (T1-T3). Cox proportional hazard models were used to evaluate the relationships between these indices and all-cause mortality. Harrell's concordance index, net reclassification improvement (NRI), and integrated discrimination improvement (IDI) were used to assess the predictive values of the CONUT score and PNI, when added to the basic risk model, which was composed of conventional CV risk factors.

RESULTS

During a median follow-up of 4.2 y, mortality from any cause occurred in 241 patients. Multivariable-adjusted Cox analyses yielded hazard ratios (HRs) [95% confidence intervals (CIs)] for the CONUT score for the mild and moderate-to-high groups of 1.38 (0.94, 2.03) and 1.98 (1.29, 3.05), respectively, compared with the low group. In addition, the HRs (95% CIs) for T1 and T2 for PNI were 1.94 (1.29, 2.92) and 0.95 (0.61, 1.48), respectively, compared with T3. The C-statistic, NRI, and IDI significantly increased when the CONUT score and PNI were added to the basic risk model.

CONCLUSIONS

In patients with CKD, the CONUT score and PNI enhance the predictive value of conventional CV risk factors for all-cause mortality.