Comorbidity burden at dialysis initiation and mortality: A cohort study

Area of Science:

• Nephrology
• Epidemiology
• Biostatistics

Background:

• High comorbidity at dialysis initiation correlates with increased mortality risk.
• Contemporary validation of comorbidity indices in dialysis patients is lacking.

Purpose of the Study:

• To evaluate the validity of the Charlson Comorbidity Index (CCI) and End-Stage Renal Disease Comorbidity Index (ESRD-CI).
• To determine the association between high comorbidity and mortality in incident dialysis patients.

Main Methods:

• A cohort study of 771 incident chronic dialysis patients from 2006-2013.
• Utilized patient charts and electronic records to classify comorbidities using CCI and ESRD-CI.
• Employed adjusted Cox proportional hazard models and Harrell's c-index to assess mortality risk and discrimination.

Main Results:

• Both CCI and ESRD-CI showed limited discrimination for death (c-indices 0.61 and 0.63, respectively).
• Higher ESRD-CI scores (≥4) were associated with a ~2-fold increased adjusted mortality risk.
• Higher CCI scores (≥4) were associated with a ~1.86- to 2.71-fold increased adjusted mortality risk.

Conclusions:

• The CCI and ESRD-CI demonstrate limited prognostic value for mortality in incident dialysis patients.
• The findings highlight the need to re-evaluate the utility of established comorbidity indices in contemporary dialysis cohorts.