Red blood cell transfusion in non-bleeding critically ill patients with moderate anemia: is there a benefit?

Purpose This study was undertaken to investigate the efficacy of red blood cell transfusion (RBCT) at reversing the deleterious effects of moderate anemia in critically ill, non-bleeding patients. Methods This was a retrospective, pair-matched (ratio 1:1) cohort study. Non-bleeding critically ill patients with moderate anemia (nadir hemoglobin level between 70 and 95 g/l), admitted to the ICU over a 27-month period, were included. Anemic patients were included upon meeting five matching criteria of having the same nadir hemoglobin (±5 g/l), APACHE II score (±5), SOFA score (±2), admission diagnostic group, and age (±5 years). Outcome events occurring over the whole ICU stay and after RBCT were collected. After hospital discharge, all patients had a 2-year follow-up period. Results Two hundred fourteen non-transfused anemic patients (NTAPs) were successfully matched with 214 transfused anemic patients (TAPs). In addition to the matching criteria, at baseline, both groups were homogenous with respect to multiple comorbidities. Compared with TAPs, NTAPs showed significantly lower rates of hospital mortality (21 vs.13 %, respectively; p < 0.05) and ICU re-admission (7.4 vs. 1.9 %, respectively; p < 0.05). Additionally, NTAPs had significantly lower rates of nosocomial infection (12.9 vs. 6.7 %, respectively; p < 0.05) and acute kidney injury (24.8 vs. 16.7 %, respectively; p < 0.05). Similar results were obtained in subgroup analysis where only more anemic patients (68 matched pairs) or patients with cardiovascular comorbidities (63 matched pairs) were considered. Conclusions RBCT does not improve the clinical outcome in non-bleeding critically ill patients with moderate anemia.