Prediction model for prolonged length of stay in patients with community-acquired pneumonia based on Japanese administrative data

Background: The length of hospital stay in community-acquired pneumonia patients is closely associated with medical costs, the burden of which is increasing in aging societies. Herein, we developed and validated models for predicting prolonged length of stay in community-acquired pneumonia patients to support efficient care in these patients.

Methods: We obtained data of 32,916 patients hospitalized for pneumonia who were discharged between 2012 and 2013 from 304 acute care hospitals in Japan. Logistic regression models were developed with prolonged length of stay as the outcome and patient characteristics as predictors. The models were internally validated using bootstrapping and externally validated using pneumonia patients discharged in 2014.

Results: The median length of stay was 11 (interquartile range, 8-17) days. The following were significant predictors of prolonged length of stay (odds ratio >1.6): age ≥75 years, Barthel index score ≤6, fraction of inspired oxygen ≥35%, Japan Coma Scale score of 100-300, anemia, muscle wasting and atrophy, bedsores, dysphasia, and methicillin-resistant Staphylococcus aureus infection. Our validation models had a c-statistic of 0.78 (95% confidence interval, 0.77-0.79) and a calibration slope of 0.98.

Conclusions: Our prediction models may help policymakers in developing strategies for the optimal management of community-acquired pneumonia patients with a focus on patients at a high risk of prolonged length of stay.