Efficacy of haemoadsorption combined with continuous renal replacement therapy in patients with rhabdomyolysis and acute kidney injury: a retrospective study

Background Clearance of circulating myoglobin is crucial to prevent further damage in patients with rhabdomyolysis (RM) and acute kidney injury (AKI). The objective of the present study was to evaluate the efficacy and safety of haemoadsorption (HA) combined with continuous renal replacement therapy (CRRT) in critically ill patients with RM and AKI. Methods Patients with RM and AKI who received CRRT + HA or CRRT with concomitant creatine kinase (CK) >10 000 IU/l in our intensive care unit (ICU) between May 2021 and December 2023 were retrospectively included. The primary outcome was 90-day mortality; secondary outcomes were kidney function recovery and CK decline rate. Adverse events were also evaluated, including hypotension, circuit clotting, albumin leakage and blood loss. Propensity score matching and Cox retrospective analysis were performed. Results A total of 111 RM patients with AKI were ultimately included. The ICU and in-hospital mortality were significantly lower in the CRRT + HA group compared with the CRRT group (ICU mortality: 18% versus 42%, P = .025; in-hospital mortality: 21% versus 42%, P = .048). However, the CRRT + HA group only showed a non-significant reduction in 90-day mortality compared with the CRRT group (47% versus 68%, P = .063). After treatment for 90 days, the number of patients with kidney function recovery was not significantly different between the CRRT + HA and CRRT groups (95% versus 84%, P = .639). Moreover, the incidence of hypotension and circuit clotting events did not increase during CRRT + HA treatment. In addition, the CRRT + HA group also appeared to have a higher rate of CK reduction and reduction of CK than the CRRT group at 24 and 48 hours after the initiation of CRRT. A multivariate Cox regression model demonstrated that CRRT + HA {hazard ratio [HR] 0.477 [95% confidence interval (CI) 0.234-0.972], P = .042}, mean arterial blood pressure [per 1 mmHg; HR 0.967 (95% CI 0.943-0.992), P = .009] and CRRT treatment duration [per 1 h; HR 0.995 (95% CI 0.992-0.998), P = .002] played a favourably important role in the survival prognosis of RM and AKI patients. In contrast, serum phosphate before RRT [per 1 mmol/l; HR 1.531 (95% CI 1.113-2.106), P = .009] and McMahon score [per 1 score; HR 1.15 (95% CI 1.006-1.313), P = .04] were independent risk factors for 90-day mortality. Conclusions CRRT combined with HA therapy reduced ICU and in-hospital mortality in patients with RM and AKI and also had a cleansing effect on creatine kinase without significant adverse events.