C - reactive protein to Albumin Ratio as a Predictor of Clinical Outcomes in Pediatric and Adult Patients

Abstract

Background: The C-reactive protein-to-albumin ratio (CAR) is a simple composite biomarker that may improve prediction of adverse clinical outcomes by integrating systemic inflammation and hypoalbuminemia.

Objective: To determine the predictive value of CAR for clinical outcomes in pediatric and adult patients.

Methodology: A hospital-based observational cohort study was conducted at Pakistan from April 2025 to March 2026. A total of 280 patients, including 112 (40.00%) pediatric and 168 (60.00%) adult patients, were recruited through consecutive sampling. Baseline CRP and serum albumin were measured, and CAR was calculated. Clinical outcomes included ICU admission, mechanical ventilation, septic shock, organ dysfunction, prolonged hospital stay, and in-hospital mortality. Associations were assessed using appropriate comparative and multivariable regression analyses, while receiver operating characteristic analysis was used to evaluate predictive performance.

Results: Adults had higher median CAR than pediatric patients [17.10 (8.21–32.74) vs. 12.94 (6.31–25.36), p=0.009]. Adverse outcomes included ICU admission in 63 (22.50%), mechanical ventilation in 32 (11.43%), septic shock in 41 (14.64%), organ dysfunction in 57 (20.36%), prolonged hospital stay in 72 (25.71%), and in-hospital mortality in 29 (10.36%) patients. CAR was significantly higher among patients with all assessed adverse outcomes (p<0.001). Adjusted analysis demonstrated significant associations between CAR and ICU admission (OR 2.31), mechanical ventilation (OR 2.68), septic shock (OR 2.91), organ dysfunction (OR 2.43), prolonged hospital stay (OR 1.94), and mortality (OR 3.57, 95% CI 1.67–7.64; p=0.001). CAR showed good predictive performance for mortality (AUC 0.861).

Conclusion: CAR demonstrated significant and clinically relevant predictive value for adverse outcomes and may serve as a useful adjunctive biomarker for early risk stratification in pediatric and adult patients.