Exertional Rhabdomyolysis: A Retrospective Population-based Study

Purpose This study aimed to evaluate the incidence and characteristics of exertional rhabdomyolysis (ER) in a population-based cohort. Methods A retrospective cohort study was performed in Olmsted County, Minnesota, from 2003 to 2015. Incident ER cases were ascertained through the Rochester Epidemiology Project medical record linkage system through electronic searches of the International Classification of Diseases, Ninth Revision, codes and clinical note text. Population incidence rate was calculated using the corresponding Rochester Epidemiology Project census populations specific to calendar year and sex. Descriptive statistics were used. Results Of the 430 patients, 431 cases met the inclusion criteria for rhabdomyolysis; 4.9% of cases (n = 20; males n = 18; Caucasian n = 17) were ER, with one recurrence. There were no deaths secondary to ER. The age- and sex-adjusted incidence rate of ER was 1.06 ± 0.24 (95% confidence interval = 0.59-1.52) per 100,000 person-years. Endurance activity (n = 7), manual labor (n = 5), and weight lifting (n = 4) were common causes. Complications included kidney injury (n = 5), mild electrolyte abnormalities (n = 10), elevated transaminases (n = 12), and minor electrocardiographic abnormalities (n = 4). A majority of patients were hospitalized (n = 16) for a median of 2 d, had mild abnormalities in renal and liver function and electrolytes, and were discharged without sequelae. Conclusion ER in the civilian population occurs at a much lower incidence than the military population. The most common causes were endurance exercise, manual labor, and weight lifting. The majority of cases were treated conservatively with intravenous fluid resuscitation during a brief hospital stay, and all were discharged without sequela. Only one case of recurrence occurred in this cohort, indicating the recurrence rate was low.