Regional citrate anticoagulation for intermittent renal replacement therapy in critically ill patients: a retrospective case-control study.

Background: Regional citrate anticoagulation (RCA) is gradually adopted for intermittent kidney replacement therapy (IRRT) in critically ill patients to mitigate circuit clotting. However, evidence comparing its efficacy and safety remains limited. This study aimed to (1) validate the safety and efficacy of regional citrate anticoagulation (RCA) compared to conventional anticoagulation avoidance during intermittent renal replacement therapy (IRRT) in a critical care nephrology cohort, and (2) establish practical criteria for selecting RCA protocols based on individualized patient bleeding and clotting risk assessments.

Methods: This retrospective study analyzed 141 critically ill patients requiring IRRT without systemic anticoagulation: RCA (n = 48) vs. heparin-free (n = 93). Primary outcomes included IRRT completion rates and circuit clotting events. Secondary outcomes comprised filter lifespan, net ultrafiltration (UF), solute clearance (Kt/V, URR), and adverse events. Multivariate regression identified clotting predictors.

Results: Circuit clotting caused 93.9% of premature terminations. The RCA group demonstrated significantly higher IRRT completion rates (87.5% vs. 53.8%, p < 0.001). Net UF was superior with RCA (1.9 ± 1.0 kg vs. 1.4 ± 0.9 kg; P = 0.010), while Kt/V, URR and the occurrence of hypocalcemia and metabolic acidosis remained comparable. Platelet count, traditional clotting factors (such as fibrinogen, PT, and aPTT), and thromboelastograms-derived parameters (such as R time and maximum amplitude) were comparable between subgroups. Multivariate analysis confirmed RCA as an independent protective factor against clotting (OR 0.121; P < 0.001), particularly in patients with platelet counts > 130 × 10⁹/L and hemoglobin > 90 g/L.

Conclusions: RCA with calcium-containing dialysate significantly improves IRRT completion rates, filter longevity, and ultrafiltration efficiency without increasing metabolic risks, in a specific group of patients with platelet counts > 130 × 10⁹/L and hemoglobin > 90 g/L, positioning RCA as a safer and more effective anticoagulation strategy for critically ill populations. Prospective trials are needed to validate these findings and to optimize RCA protocols.

Clinical trial number: Not applicable.