Clinical outcomes of rhabdomyolysis & validation of McMahon Score for risk prediction.

Background objectives: Rhabdomyolysis in tropics has a unique aetiology and clinical profile. The objective of this study was to determine the aetiology and clinical outcomes of rhabdomyolysis and validate the McMahon risk prediction score in affected individuals from south India.

Methods: A retrospective study of affected individuals with rhabdomyolysis admitted to a tertiary care hospital in south India, between January 2015 and June 2020, was undertaken. In-patients who were ≥15 yr in age and had creatinine phosphokinase ≥5000 U/l were included in the study. Cardiac, stroke, chronic muscular diseases and chronic kidney disease on maintenance haemodialysis were excluded. The incidence of acute kidney injury (AKI) in this group was calculated. Other clinical outcomes determined were 28-day mortality, proportion of individuals who required renal replacement therapy (RRT), intensive care unit (ICU) admission, vasopressors, mechanical ventilation (MV), number of days on mechanical ventilator and length of stay in ICU and hospital. Validation of McMahon risk prediction score for the requirement of RRT and mortality was performed.

Results: Major aetiologies identified in the 75 study participants included were infections, trauma and seizures. Twenty eight-day mortality was 24 per cent (n=18). AKI incidence was 68 per cent, out of which 43.1 per cent had RRT. AKI in all survivors became dialysis independent. Vasopressors, MV and ICU requirement were 30.7, 32 and 77.3 per cent, respectively. Receiver operator characteristic curve for RRT and mortality risk prediction based on the McMahon Score showed a sensitivity of 71.4 per cent and specificity of 77.8 per cent for a cut-off ≥7.8.

Interpretation conclusions: Rhabdomyolysis in tropics is associated with significant organ dysfunction and mortality. Although the incidence of AKI and RRT is high, the overall renal outcome is good among survivors. The wide confidence intervals for the area under curve for McMahon Score limit its predictability for RRT and mortality.