Charlson Comorbidity Index for Prediction of Outcome of Acute Kidney Injury in Critically Ill Patients

Abstract

Introduction: This study aimed to determine predictors of outcomes in critically ill patients with acute kidney injury (AKI), and to study the impact of the Charlson Comorbidity Index (CCI) as a prognostic indicator.

Materials and methods: This retrospective study included critically ill patients who were admitted with AKI or developed AKI during their hospital stay. The impact of comorbidity was evaluated by the CCI, while severity of AKI was assessed by the RIFLE criteria.

Results: The mean age of 786 patients with AKI was 59.0 ± 17.0 years (59% men). The most common cause was sepsis in 51% of the patients. In-hospital mortality rate was 42%. The need for mechanical ventilation (odds ratio [OR], 1.93; 95% confidence interval [CI], 1.23 to 3.04), vasoactive drugs (OR, 9.67; 95% CI, 6.35 to 14.73), dialysis (OR, 1.78; 95% CI, 1.14 to 2.78), failure class of RIFLE criteria (OR, 2.02; 95% CI, 1.00 to 4.08), and a CCI greater than 6 (OR, 2.20; 95% CI, 1.38 to 3.52) were independently associated with mortality. At 90 days of follow-up, 6% of the patients were dialysis dependent, while 32% and 62% had partial and complete recovery, respectively. In multivariable analysis, a CCI greater than 6 (OR, 0.47; 95% CI, 0.26 to 0.83), need for dialysis in hospital (OR, 0.31; 95% CI, 0.17 to 0.54), and failure class (OR, 0.19; 95% CI, 0.07 to 0.55) were independent predictors of poor renal outcomes.

Conclusions: The CCI independently predicts in-patient mortality and poor renal outcomes in patients with AKI.