Pakistan Journal of Pharmaceutical Sciences

Abstract: Background: Early identification of high-risk individuals is essential to guide infection-prevention strategies and optimize antibiotic stewardship in this vulnerable population. Objectives: To identify independent risk factors associated with hospital-acquired infections in elderly ICU patients following antibiotic use and to develop and internally validate a clinical risk prediction model for early infection detection. Methods: A retrospective cohort study was conducted in the ICU of Nanjing First Hospital, Nanjing Medical University. A total of 120 patients aged ?65 years, with ICU stay >48 hours, no documented infection at ICU admission and antibiotic exposure within 48 hours before or at ICU admission were included. Demographic data, comorbidities, Sequential Organ Failure Assessment (SOFA) scores, antibiotic exposure characteristics, invasive device use and nutritional support were collected from electronic health records. Results: Hospital-acquired infections occurred in 46 patients (38.3%). Independent predictors included advanced age (odds ratio [OR] 1.08 per year), higher SOFA score (OR 1.25 per point), diabetes mellitus (OR 1.45), chronic kidney disease (OR 1.65), use of central venous catheters (OR 1.75), mechanical ventilation (OR 1.85), Foley catheterization (OR 1.55), broad-spectrum antibiotic use (OR 1.50), longer antibiotic duration (OR 1.20 per day) and prolonged ICU stay (all p<0.05). The prediction model demonstrated good discrimination (AUC-ROC = 0.82), which improved slightly after variable refinement (AUC-ROC = 0.83). Cross-validated performance remained robust (AUC = 0.80). Conclusion: A multivariable risk prediction model using routinely available clinical parameters demonstrated good internal validity and may assist clinicians in early identification of high-risk patients, enabling targeted infection prevention and improved antibiotic stewardship.