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 This is a post hoc analysis based on The TRIFE - a randomized controlled trial. Frail anemic patients from the Orthopedic Surgical Ward at Aarhus University Hospital were enrolled consecutively between January 18, 2010 and June 6, 2013. These patients (aged >= 65 years) had been admitted from nursing homes for unilateral hip fracture surgery. 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 tenth 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 on day 10 increased the risk of 90-day 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.