Supplementary Material for: Rhabdomyolysis among Critically Ill Combat Casualties: Long-Term Outcomes

Background: Although rhabdomyolysis has been associated with acute kidney injury and mortality in the short term, the long-term consequences of an episode of rhabdomyolysis remain unknown. We sought to identify the long-term outcomes of rhabdomyolysis, including mortality, renal function, and incidence of hypertension (HTN), among service members initially admitted to the intensive care unit after sustaining a combat injury in Iraq or Afghanistan between February 1, 2002 and February 1, 2011. Methods: Information on age, sex, injury severity score, mechanism of injury, serum creatinine, burn injury, presenting mean arterial pressure, and creatine kinase were retrospectively collected and analyzed for 2,208 patients. Standard descriptive tests were used to compare characteristics of patients with and without rhabdomyolysis. Competing risk Cox proportional hazards models were performed to assess the associated risk of rhabdomyolysis with both HTN and poor renal function. Results: While rhabdomyolysis was associated with HTN on univariate analysis (hazard ratio [HR] 1.30, 95% CI 1.03–1.64; p = 0.029), this difference did not persist on multivariable analysis (HR 1.27, 95% CI 0.99–1.62; p = 0.058). The median estimated glomerular filtration rate (eGFR) was 119 (interquartile range [IQR] 103–128) among those with rhabdomyolysis, compared with 108 (IQR 94–121) in the group without rhabdomyolysis (p < 0.001). Conclusion: After adjustment, patients with rhabdomyolysis were not at an increased risk of HTN compared to patients without rhabdomyolysis. eGFR was paradoxically higher in patients with rhabdomyolysis. There was no association found between rhabdomyolysis and mortality.