Comparison of Operation Iraqi Freedom and Patient Workload Generator injury distributions

The Patient Workload Generator (PATGEN) simulation model is an important part of the Army Medical Department force requirement planning. The current version of the PATGEN model is based on historical major combat operations such as World War II and the Korean War. The purpose of this study was to determine whether there was a significant difference between injury distributions used in the PATGEN model and the injury distributions based on the data from Operation Iraqi Freedom (OIF). To make the comparison feasible, the PATGEN injury categories were created using the Barell Injury Matrix. Analyses were performed using two independent OIF data sources, the Joint Theater Trauma Registry and the Standard Inpatient Data Record. Based on X2 test results, both analyses suggest a significant difference between PATGEN and OIF injury distributions. A major concern is the underestimation by PATGEN of battle injuries with multiple wounds. The findings support future use of data-driven diagnosis-based injury distributions for current operations and new more flexible simulation models that will allow for changes in injury probability distributions.