A Case-Control Analysis of Bone Stress Injury on Advancement and Health Care Utilization in US Air Force Basic Military Trainees

Abstract

Introduction Every year, approximately 35,000 recruits enter the United States Air Force Basic Military Training (BMT). Musculoskeletal problems are particularly vexing for BMT because a broad array of differentials render definitive diagnosis burdensome and while most sufferers will fully recover, healing often requires protracted training delays resulting in increased unrecoverable training costs to the program. The purpose of this study is to conduct a case-control study of basic military trainees entering service from 2012 to 2015 to assess detectable differences in demographics, retention, and health care utilization. Materials and Methods This is a retrospective case-control study of existing data and records obtained from existing and active information record systems for individuals who attended BMT between the years 2012 and 2015. Cohort assignment was based on incidence of first stress fracture diagnosis (i.e., having a select diagnosis code in one’s medical record) relative to arrival at BMT. Health care utilization is operationalized as medical encounter frequencies and associated international classification of disease (ICD) codes occurring for all patients from BMT recruit date of arrival to 6 months post-graduation (i.e., 180 days). Results The primary dataset includes 132,359 distinct individuals, of which 129,637 (98%) had no history of stress fracture diagnosis and 1,487 (1%) of which have a diagnosis of stress fracture more than 60 days after arrival at BMT; these are assigned to the CONTROL group. There are 1,235 (0.9%) assigned to the CASE group. CASE members presented with 30.1 unique ICD-10 codes post-graduation compared to 6.3 in the CONTROL group. Six of the top thirteen ICD-10 codes were musculoskeletal in nature and all presented significantly higher rates for the CASE group. Conclusions Trainees who suffered a bone stress injury (BSI) during the United States Air Force BMT advanced in rank on par with trainees who did not, but BSI sufferers exhibited greater health care utilization than those who did not suffer BSI. The cost to replace a trainee unable to complete BMT is considerable; however, it is also important to consider the reduction in resiliency and readiness to the Department of Defense and the financial burdens from increased health care utilization. The 2-fold increase in BSI presentation in the graduated control group reflects that more needs to be done for all populations to identify better proactive efforts to foundationally support wellness and prevention rather than accept injury as the status quo.