Serum creatine kinase levels are not associated with an increased need for continuous renal replacement therapy in patients with acute kidney injury following rhabdomyolysis

Severe rhabdomyolysis can lead to acute kidney injury (AKI). Previous studies have reported a benefit from continuous renal replacement therapy (CRRT) for rhabdomyolysis-associated AKI. Here, we investigated the potential for serum creatine kinase (CK) levels to be used as a marker for CRRT termination in patients with AKI following rhabdomyolysis. We compared different CK levels in patients after CRRT termination and observed their clinical outcomes. We retrospectively collected 86 cases with confirmed rhabdomyolysis-associated AKI, who were receiving CRRT in Tongji Hospital. Patients’ renal functions were assessed within 24 h of intermission, patients with urine output ≥ 1,000 mL and serum creatinine ≤ 265 umol/L were considered for CRRT termination. After termination, 33 patients with a CK > 5,000 U/L were included in an experimental group, and 53 patients with a CK < 5,000 U/L were included in a control group. Clinical outcomes were compared between the two groups. Higher CK levels, as well as worse renal functions, predicted the necessity of CRRT. After CRRT termination, the in-hospital mortality (p = 0.389) and Multiple Organ Dysfunction Syndrome (MODS) incidence (p = 0.064) were similar between the two groups, while the experimental group showed a significantly shorter in-hospital length of stay (p = 0.026) and Intensive Care Unit (ICU) length of stay (p = 0.038). CRRT termination may be independent of CK levels for patients with rhabdomyolysis-associated AKI, and this is contingent on their renal functions having recovered to an appropriate level.