External validation and revision of Penn incisional hernia prediction model: A large-scale retrospective cohort of abdominal operations
1 Department of Clinical Epidemiology and Biostatistics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
2 Department of Surgery, Faculty of Medicine Vajira Hospital, Navamindradhiraj University, Bangkok, Thailand
3 Information Technology Department, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
4 Centre for Public Health, School of Medicine, Dentistry, and Biomedical Sciences, Queen's University Belfast, Northern Ireland, UK
5 School of Medicine and Public Health, University of Newcastle, Australia
6 Hunter Medical Research Institute, Newcastle, Australia
7 Department of Surgery, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
Abstract
Background: Incisional hernia (IH) manifests in 10–15% of abdominal surgeries and patients at elevated risk should be identified for prophylactic intervention. This study aimed to externally validate the Penn hernia risk calculator.
Methods: The Ramathibodi abdominal surgery cohort was constructed by linking relevant hospital databases from 2010 to 2021. Penn hernia risk scores were calculated according to the original model and externally validated using a seven-step approach. An updated model adding four additional predictors (age, immunosuppressive medication, ostomy reversal, and transfusion) to the three original predictors (BMI, chronic liver disease, and open surgery) was also evaluated.
Results: A total of 12,155 abdominal operations were assessed. The original Penn model yielded fair discrimination (AUC 0.645; 95% CI 0.607–0.683). The updated model achieved an acceptable AUC of 0.733 (95% CI 0.698–0.768) with an observed/expected ratio of 0.968 (0.848–1.088).
Conclusions: The updated model achieved improved discrimination and calibration performance, and should be considered for the identification of high-risk patients for hernia prevention strategy.
