RESUMO
OBJECTIVE: To investigate the role of dementia in pneumonia among geriatric patients with hip fracture and further develop an algorithm for stratifying risk of developing postoperative pneumonia. METHODS: The algorithm was developed after retrospectively analyzing 1344 hip fracture patients in the National Clinical Research Center for Orthopedics, Sports Medicine, and Rehabilitation from 1992 to 2012. Twenty-eight variables were analyzed for evaluating the ability to predict postoperative pneumonia. The validation of the algorithm was performed in the MIMIC-III database after enrolling 235 patients. RESULTS: One thousand five hundred and seventy-nine patients were enrolled, 4.69% patients had postoperative pneumonia in our hospital, and 17.02% suffered pneumonia in the MIMIC-III database. Dementia patients had more postoperative pneumonia (12.68% vs 4.24%, P = 0.0075), as compared with patients without dementia. The algorithm included nine predictors: dementia, age, coronary heart disease, the American Society of Anesthesiologists score, surgical method, mechanical ventilation, anemia, hypoproteinemia, and high creatinine. Internal validation showed the algorithm with dementia could improve predictive performance, while external validation found the algorithm with or without dementia both had similar and good predictive ability. CONCLUSIONS: The algorithm has the potential to be a pragmatic risk prediction tool to calculate risk of pneumonia in clinical practice and it may also be applicable in critically ill hip fracture patients with dementia.