Creatinine as predictor value of mortality and acute kidney injury in rhabdomyolysis

Background Rhabdomyolysis (RB) is a syndrome characterised by decomposition of skeletal muscle that could be life threatening, so the identification of biomarkers of its severity could help us in its treatment. Creatine kinase (CK) is usually taken as a reference in patients with RB in order to stratify prognosis, however that is not probably the most effective parameter. Aims The present study was designed to analyse the specific features and mortality of patients with RB and the relation between creatinine, CK and mortality. Methods Retrospective cohort analysis among patients admitted to San Pedro Hospital in Logroño (Spain) with RB (CK levels higher than 2000 U/L) diagnosed since 1 January 2009 until 31 December 2; 013 522 patients with RB patients diagnosed of RB were collected. The aetiology and the analytical feature (creatinine, CK, calcium, phosphorus, pH and bicarbonate), as well as 30‐year mortality, were investigated. Results Among the 522 patients, there were 138 deaths. Four patients required renal replacement therapy. The most common cause of RB was trauma (29%). Infectious aetiology had the highest mortality (41.2%). The median CK was 3451 u/L (interquartile range 3348), and the mean creatinine at admission was 132.6 umol/L (±110.5). Initial CK levels do not have predictive ability on mortality or renal dysfunction in contrast to initial creatinine values. Each state of acute kidney injury (AKI) increased mortality compared with those who have not presented this renal dysfunction (P < 0.0001). Age, calcium, phosphorus, bicarbonate and pH are associated with AKI. Conclusion Despite being a diagnostic marker for RB, initial CK levels do not predict mortality. However, creatinine initial levels are related to progression to acute renal injury and mortality at 30 days.