Peak creatinine kinase level is a key adjunct in the evaluation of critically ill trauma patients

•Single level 1 trauma center, 78% blunt, 79% male, median age 40 (27-56) years old.•The median time to peak CK level was 17 h overall and 27 h in patients that ultimately peaked over 5000.•Adjusting for covariates, mean peak CK was lower in older (age ≥ 50) compared to younger patients (1,637 vs 2,604, p < 0.0001).•Older patients are more likely to develop AKI at lower CK levels.

BackgroundElevated creatinine kinase (CK) can indicate rhabdomyolysis, a risk factor for acute kidney injury (AKI). We investigated risk factors and clinical significance of peak CK levels.MethodsRetrospective analysis, adult trauma patients. Logistic regression was used to identify risk factors for elevated CK and AKI.Results3240 trauma patients were analyzed; median time to peak CK was 17 h and 347 patients had peak CK > 5000. On multivariable analysis, younger males with severe injury were more likely to have peak CK > 5000 and peak CK > 5000 was an independent risk factor for AKI (AOR 3.79).Although peak CK levels were significantly lower in older patients (1,637U/L vs 2,604U/L), older patients were more likely to develop AKI at lower CK levels.ConclusionsCK levels commonly peak within 1-2 days after admission. Despite lower peak CK levels, older patients are more likely to develop AKI. These data may support more rigorous CK monitoring and lower intervention threshold in older patients.