Estimating selected disease and nonbattle injury Echelon I and Echelon II outpatient visits of United States soldiers and Marines in an operational setting from corresponding Echelon III (hospitalizations) admissions in the same theater of operation.

Currently, disease and nonbattle injury estimates are based on hospital admission logs and not on battalion aid stations nor medical company patient logs. A significant amount of morbidity can be overlooked and can mislead commanders and their staffs into believing that their unit is at a higher strength level. The objective of this article is to provide a tool for estimating these "hidden" disease and nonbattle injury cases. Nine weeks of military hospitalization data (687 admissions) separated into 14 diagnosis categories were compared with respective outpatient morbidity data (12,109 outpatient visits) during Operation Restore Hope in Somalia in 1993. Proportionate values and 95% confidence intervals were calculated for 5 of the 14 diagnostic categories and total morbidity. These proportionate values were then used to show how disease and nonbattle injury (total and diagnosis category) could be estimated based on hospitalization admissions during a similar military operation. Mission and geographical location information should be considered when using this model, along with other medical planning publications.