An observational study on rhabdomyolysis in the intensive care unit. Exploring its risk factors and main complication: acute kidney injury

Abstract

Background: Because neither the incidence and risk factors for rhabdomyolysis in the ICU nor the dynamics of its main complication, i.e., rhabdomyolysis-induced acute kidney injury (AKI) are well known, we retrospectively studied a large population of adult ICU patients (n = 1,769).

Methods: CK and sMb (serum myoglobin) and uMb (urinary myoglobin) were studied as markers of rhabdomyolysis and AKI (RIFLE criteria). Hemodialysis and mortality were used as outcome variables.

Results: Prolonged surgery, trauma, and vascular occlusions are associated with increasing CK values. CK correlates with sMb (p < 0.001) and peaks significantly later than sMb or uMb.The logistic regression showed a positive correlation between CK and the development of AKI, with an OR of 2.21. Univariate logistic regression suggests that elevations of sMb and uMb are associated with the development of AKI, with odds ratios of 7.87 and 1.61 respectively. The ROC curve showed that for all three markers a significant correlation with AKI, for sMb with the greatest area under the curve. The best cutoff values for prediction of AKI were CK > 773 U/l; sMb > 368 μg/l and uMb > 38 μg/l respectively.

Conclusions: Because it also has extrarenal elimination kinetics, our data suggest that measuring myoglobin in patients at risk for rhabdomyolysis in the ICU may be useful.

Figure 1

ROC curve: predictive value of creatine kinase, serum and urinary myoglobin. All three markers show significant correlation with acute kidney injury. Serum myoglobin has clearly the best predictive value. CK, creatine kinase; sMb, serum myoglobin; uMb, urinary myoglobin; cat, categorical (CK <170 U/L, CK 170–1,000 U/L, CK 1,000–5,000 U/L and CK >5,000 U/L).