Charlson comorbidity index in predicting outcomes among patients in the medical intensive care unit at a tertiary care university hospital: A cross-sectional study

Abstract

Background: In critical care, comorbidities significantly influence outcomes, but they are often underutilized in real-time decision-making. The Charlson Comorbidity Index (CCI), a widely validated tool for quantifying comorbid burden, offers a practical way to assess prognosis in intensive care unit (ICU) patients. This study was planned to explore the predictive utility of CCI alone in determining patient outcomes in a rural Indian ICU setting. Methodology: This prospective, cross-sectional study was conducted from April 2023 to March 2025 at a tertiary care center in central India. A total of 700 adult patients admitted to the medical ICU were included, excluding those with <24-hour survival, pregnancy, or hematological/immunological malignancies. CCI scores were calculated at admission based on 19 predefined comorbidities. Outcomes such as survival, mortality, mechanical ventilation requirement, and duration of stay were recorded and analyzed. Results: Among the 700 patients, the majority were male (67.7%) and aged between 41–60 years. Patients with CCI scores >3 were significantly older (mean age: 58.9 years) compared to those with CCI <3 (mean age: 40.6 years). A higher CCI was associated with increased mortality (20.8% vs. 13.5%), greater need for mechanical ventilation (24.3% vs. 16.9%), and reduced discharge rates. These associations were statistically significant ( p < 0.001). The receiver operating characteristic (ROC) analysis revealed a fair predictive capacity of CCI for in-hospital mortality, with an area under the curve (AUC) of 0.635. At an optimal cutoff of 3.5, the CCI demonstrated good sensitivity (80.9%) but limited specificity (29.6%). Conclusion: The CCI is a valuable, easy-to-use tool for assessing the prognostic outlook of ICU patients, especially in low-resource settings. Although its standalone predictive power for mortality is moderate, its high sensitivity makes it a useful screening tool to identify high-risk patients early during ICU admission. The findings underscore the need to incorporate structured comorbidity assessment into critical care workflows, particularly where advanced physiological scoring systems may not be readily available.