Blood transfusion strategy and risk of postoperative delirium in nursing homes residents with hip fracture: A post hoc analysis based on the TRIFE randomized controlled trial

Objectives: To investigate whether a liberal blood transfusion strategy (Hb levels ≥11.3 g/dL (7 mmol/L)) reduces the risk of postoperative delirium (POD) on day 10, among nursing home residents with hip fracture, compared to a restrictive transfusion strategy (Hb levels ≥9.7 g/dL (6 mmol/L)). Furthermore, to investigate whether POD influences mortality within 90 days after hip surgery. Methods: A post-hoc analysis based on The TRIFE randomized controlled trial. Consecutive recruitment of frail anemic patients (aged ≥65 years), residing in nursing homes suffering from unilateral hip fracture, admitted to the Department of Orthopedic Surgery, Aarhus University Hospital in the period from January 18th, 2010 to June 6th, 2013. After surgery 179 patients were included in this study. On the first day of hospitalization, all enrolled patients were examined for cognitive impairment (assessed by MMSE) and delirium (assessed by CAM). Delirium was also assessed on the 10th postoperative day. Results: The prevalence of delirium was 10% in patients allocated to a liberal blood transfusion strategy (LB) and 21% in the group with a restrictive blood transfusion strategy (RB). LB prevents development of delirium on day 10, compared to RB, Odds Ratio 0.41 (95% CI: 0.17-0.96), p=0.04. Development of POD day 10 increased the risk of 90 days death, Hazard Ratio 3.14 (95% CI 1.72-5.78), p<0.001. Conclusion: In nursing home residents undergoing surgery for hip fracture maintaining hemoglobin level above 11.3 g/dL reduces the rate of POD on day 10 compared to a RB. Development of POD is associated with increased mortality.