Prognostic Factors Associated with Pneumonia in Patients with Traumatic Brain Injury: A Systematic Review and Meta-Analysis

Background: Traumatic brain injury (TBI) is a leading cause of morbidity and mortality worldwide, often complicated by hospital-acquired pneumonia (HAP) or ventilator-associated pneumonia (VAP). These infections may contribute to prolonged hospitalizations and increased morbidity. We conducted a systematic review and meta-analysis to identify predicting factors associated with the development of pneumonia (HAP or VAP) in patients hospitalized following acute TBI. Methods: We conducted a comprehensive search of Medline and Embase from inception to May 12 ^th , 2025. We included studies that investigated prognostic factors for HAP or VAP in adult patients admitted to hospital with TBI and adjusted for known cofounders. We pooled adjusted odds ratios (aORs) using a random-effects model. We assessed risk of bias using the QUIPS tool and certainty of findings using GRADE methodology. Results: We included 21 studies involving 7,856 patients. Prognostic factors with a moderate or high association of developing HAP or VAP include male sex (aOR 1.52, 95% CI 1.16 – 2.01; high certainty), lower Glasgow Coma Scale at any time (aOR 6.36, 95% CI 1.91 – 21.14; moderate certainty), chest injury severity (aOR 1.56, 95% CI 1.02-2.40; moderate certainty), barbiturate use (aOR 1.83, 95% CI 0.88-3.83; moderate certainty), and the need for invasive mechanical ventilation (aOR 6.22, 95% CI 4.05 – 9.55; moderate certainty). We also found that early antibiotic use (aOR 0.40, 95% CI 0.23 – 0.72; moderate certainty) are probably associated with a reduced incidence of pneumonia. Conclusion: Pneumonia in TBI patients is influenced by patient characteristics, injury severity, and treatment related factors. Recognizing these risk factors may guide early interventions to reduce pneumonia and improve patient outcomes. Level of Evidence: Systematic review/meta-analysis