Effect of red blood cell transfusion strategies on ICU-acquired infection in patients with sepsis: A target trial emulation using the Medical Information Mart for Intensive Care IV database

Purpose To estimate the per-protocol effect of red blood cell (RBC) transfusion strategies on ICU-acquired infection in critically ill adults with sepsis using a target trial emulation framework. We evaluated whether restrictive strategy and liberal strategy, defined by hemoglobin (Hgb) thresholds, differ in their effect on ICU-acquired infection during ICU stay. Methods We conducted a target trial emulation using the MIMIC-IV database and included adults who met Sepsis criteria at ICU admission. Clones were assigned to restrictive or liberal transfusion strategies. Under the restrictive strategy, RBC transfusion was permitted only when Hgb was [≤]7.0 g/dL, whereas under the liberal strategy, transfusion was permitted when Hgb was >7.0 g/dL. The primary outcome was the first ICU-acquired infection occurring at least 72 hours after ICU admission. Per-protocol effects were estimated using a clone-censor-weight approach with a marginal structural model. A parametric g-formula was used as a complementary analysis that jointly modeled ICU discharge and ICU mortality as competing events to derive strategy-specific 28-day cumulative incidences and risk differences. Results 8 Among 4,013 eligible ICU stays, the liberal-versus-restrictive comparison provided little evidence of a difference in the risk of ICU-acquired infection (adjusted conditional OR, 0.954; 95% CI, 0.797 to 1.142). In the complementary g-formula analysis, the 28-day risk difference for the liberal versus restrictive comparison was -0.02 percentage points (95% CI, -0.15 to 0.11), consistent with the primary analysis. Findings were generally robust across prespecified subgroup and sensitivity analyses. Conclusion In this target trial emulation of adults with sepsis, we observed no clinically meaningful difference in ICU-acquired infection between RBC transfusion strategies defined by hemoglobin thresholds.