Liberal versus restrictive blood transfusion strategy: 3-year survival and cause of death results from the FOCUS randomised controlled trial

Background: Blood transfusion might affect long-term mortality by changing immune function and thus potentially increasing the risk of subsequent infections and cancer recurrence. Compared with a restrictive transfusion strategy, a more liberal strategy could reduce cardiac complications by lowering myocardial damage, thereby reducing future deaths from cardiovascular disease. We aimed to establish the effect of a liberal transfusion strategy on long-term survival compared with a restrictive transfusion strategy.

Methods: In the randomised controlled FOCUS trial, adult patients aged 50 years and older, with a history of or risk factors for cardiovascular disease, and with postoperative haemoglobin concentrations lower than 100 g/L within 3 days of surgery to repair a hip fracture, were eligible for enrolment. Patients were recruited from 47 participating hospitals in the USA and Canada, and eligible participants were randomly allocated in a 1:1 ratio by a central telephone system to either liberal transfusion in which they received blood transfusion to maintain haemoglobin level at 100 g/L or higher, or restrictive transfusion in which they received blood transfusion when haemoglobin level was lower than 80 g/L or if they had symptoms of anaemia. In this study, we analysed the long-term mortality of patients assigned to the two transfusion strategies, which was a secondary outcome of the FOCUS trial. Long-term mortality was established by linking the study participants to national death registries in the USA and Canada. Treatment assignment was not masked, but investigators who ascertained mortality and cause of death were masked to group assignment. Analyses were by intention to treat. The FOCUS trial is registered with ClinicalTrials.gov, number NCT00071032.

Findings: Between July 19, 2004, and Feb 28, 2009, 2016 patients were enrolled and randomly assigned to the two treatment groups: 1007 to the liberal transfusion strategy and 1009 to the restrictive transfusion strategy. The median duration of follow-up was 3·1 years (IQR 2·4-4·1 years), during which 841 (42%) patients died. Long-term mortality did not differ significantly between the liberal transfusion strategy (432 deaths) and the restrictive transfusion strategy (409 deaths) (hazard ratio 1·09 [95% CI 0·95-1·25]; p=0·21).

Interpretation: Liberal blood transfusion did not affect mortality compared with a restrictive transfusion strategy in a high-risk group of elderly patients with underlying cardiovascular disease or risk factors. The underlying causes of death did not differ between the trial groups. These findings do not support hypotheses that blood transfusion leads to long-term immunosuppression that is severe enough to affect long-term mortality rate by more than 20-25% or cause of death.

Funding: National Heart, Lung, and Blood Institute.