Risk Factors for Rhabdomyolysis in the U.S. Army

The standardized mortality rate of rhabdomyolysis (RM) in Active Duty U.S. Army Soldiers is considerably higher than in the civilian population. RM occurs when large amounts of intracellular contents from damaged skeletal muscle escape into circulation, leading to serious sequelae (e.g., acute renal failure, hyperkalemia, compartment syndrome). Extended physical exertion, especially in hot environments, and trauma can precipitate RM. The aim of this study was to identify RM risk factors among U.S. Active Duty Army (ADA) Soldiers.

This nested case-control study used data from the Total Army Injury and Health Outcomes Database (years 2004-2006) to examine RM among ADA male Soldiers. Demographic and occupational variables were identified as potential risk factors. Each RM case was age and date-matched to 4 controls. Adjusted odds ratios (OR) were computed using conditional logistic regression analyses.

From years 2004 to 2006, 1,086 Soldiers (0.19%) met the study criteria for clinically diagnosed RM. Three variables were found to increase the odds of acquiring RM: (1) prior heat stroke, OR 4.95 (95% confidence interval [CI] 1.1-21.7); (2) self-reported Black race, OR 2.56 (95% CI 2.2-3.0); and (3) length of service (0-90 days), OR 2.05 (95% CI 1.6-2.7).

There is a substantially greater likelihood for male U.S. Army Soldiers to develop RM who: (1) have had a prior heat injury, (2) self-report in the Black racial category, and (3) who are within the initial 90 days of service. Greater awareness of the risk factors associated with RM may improve force health protection and readiness through targeted mitigation strategies.