Risk Factors for Postoperative Pneumonia in the Elderly Following Hip Fracture Surgery: A Systematic Review and Meta-Analysis

Introduction: Pneumonia is a serious complication following hip fracture surgery in older people. However, the prevalence and risk factors of postoperative pneumonia (POP) are not well-established. This study identified pre- and peri-operative factors associated with the development of POP following hip fracture surgery. Methods: We searched the Cochrane library, PubMed, and Embase databases for relevant articles published up to June 2021. Studies involving older patients who underwent hip fracture surgery were considered if they detailed the demographic or surgical characteristics of the participants. For all analyses, the pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated. Results: A total of 24 studies (288819 participants) were included. The overall prevalence of POP following hip fracture surgery was 5.0%. There were 36 risk factors for POP, and the meta-analysis included the five most common: delayed surgery (OR: 1.84, 95% CI: 1.29-2.63), low serum albumin (OR: 2.34, 95% CI: .82-6.73), chronic respiratory diseases (OR: 2.42, 95% CI: 1.82-3.24), increased age (OR: 1.25, 95% CI:1.11-1.40), and male sex (OR: 2.22, 95% CI: 2.00-2.47). Conclusions: The prevalence of POP was 5.0% following hip fracture surgery in the elderly. Older age, male sex, chronic respiratory diseases, delayed surgery, and low serum albumin were significant risk factors. Clinicians treating hip fracture patients must remain be aware of these risk factors.