Score Predicts Kidney Failure or Death in Rhabdomyolysis

A risk prediction score calculated with the use of routine admission data performs well in predicting the risk of renal replacement therapy (RRT) or mortality in patients with rhabdomyolysis, according to a study in JAMA Internal Medicine.

The researchers analyzed data from 2731 patients treated for rhabdomyolysis at two hospitals between 2000 and 2011. All had creatine phosphokinase levels greater than 5000 U/L within 3 days of admission. The risk prediction score was developed with the use of data from 1397 patients treated at one hospital and was validated by the use of data from 974 patients at the other hospital. The main outcome of interest was a composite of continuous RRT and in-hospital death.

Overall, 8.0 percent of patients required continuous RRT, 14.1 percent died in the hospital, and 19.0 percent met either outcome. Rates of the composite outcome were highest for patients with rhabdomyolysis associated with cardiac arrest (58.5 percent), compartment syndrome (41.2 percent), and sepsis (39.3 percent). Other independent risk factors included older age, female sex, and baseline creatinine, creatine phosphokinase, phosphate, calcium, and bicarbonate levels.

A risk score comprising these variables performed well in identifying rhabdomyolysis patients at high risk of RRT or death, with C statistics of 0.82 in the derivation cohort and 0.83 in the validation cohort. In the latter group, the composite outcome rates were 2.3 percent in patients with a risk score less than 5 versus 61.2 percent for those with a score greater than 10. For a risk score less than 5, the negative predictive value was 97.7 percent and the positive predictive value was 27.2 percent.

Patients with rhabdomyolysis are at risk of potentially life-threatening acute kidney injury. The new risk prediction score, based on readily accessible demographic, clinical, and laboratory variables, performs well in identifying patients at lower and higher risk of continuous RRT and in-hospital mortality. The authors believe their score will be most useful for triage of patients evaluated in the emergency department [McMahon GM, et al. A risk prediction score for kidney failure or mortality in rhabdomyolysis. JAMA Intern Med 2013; 173:1821–1827].

January 2014 (Vol. 6, Number 1)​