Risk factors for hospital-acquired pneumonia in hip fracture patients: A systematic review and meta-analysis

Background: This study aimed to comprehensively assess the prevalence and risk factors for Hospital-acquired pneumonia (HAP) in hip fracture patients by meta-analysis. Methods: Systematically searched 4 English databases and 4 Chinese databases from inception until October 20, 2022. All studies involving risk factors of HAP in patients with hip fractures will be considered. Newcastle-Ottawa Scale was used to evaluate the quality of the included studies. The results were presented through Review Manager 5.4 with the pooled odds ratio (OR) and 95% confidence interval. Results: Of 35 articles included in this study, the incidence of HAP was 8.9%. 43 risk factors for HAP were initially included, 23 were eventually involved in the meta-analysis, and 21 risk factors were significant. Among them, the 4 most frequently mentioned risk factors were as follows: Advanced age (OR 1.07, 95% CI 1.05-1.10), chronic obstructive pulmonary disease (COPD) (OR 3.44, 95% CI 2.83-4.19), time from injury to operation (OR 1.09, 95% CI 1.07-1.12), time from injury to operation >= 48 hours (OR 3.59, 95% CI 2.88-4.48), and hypoalbuminemia < 3.5g/dL (OR 2.68, 95% CI 2.15-3.36). Discussion: Hip fracture patients diagnosed with COPD have a 3.44 times higher risk of HAP compared to the general hip fracture patients. The risk of HAP also increases with age, with patients over 70 having a 2.34-fold higher risk and those over 80 having a 2.98-fold higher risk. These findings highlight the need for tailored preventive measures and timely interventions in vulnerable patient populations. Additionally, hip fracture patients who wait more than 48 hours for surgery have a 3.59-fold higher incidence of HAP. This emphasizes the importance of swift surgical intervention to minimize HAP risk. However, there are limitations to consider in this study, such as heterogeneity in selected studies, inclusion of only factors identified through multivariate logistic regression, and the focus on non-randomized controlled trial studies.