The Interaction Between Per-admission β-Blocker Therapy, The Revised Cardiac Risk Index, and Mortality in Geriatric Hip Fracture Patients

BACKGROUND: An association between beta-blocker (BB) therapy and a reduced risk of major cardiac events and mortality in patients undergoing surgery for hip fractures has previously been demonstrated. Furthermore, a relationship between an increased Revised Cardiac Risk Index (RCRI) score and a higher risk of postoperative mortality has also been detected. The purpose of the current study was to investigate the interaction between BB therapy and RCRI in relation to 30-day postoperative mortality in geriatric patients after hip fracture surgery. METHODS: All patients over 65 years of age who underwent primary emergency hip fracture surgery in Sweden between January 1, 2008 and December 31, 2017, except for pathological fractures, were included in this retrospective cohort study. Patients were divided into cohorts based on their RCRI score (RCRI 1, 2, 3, and ≥ 4) and whether they had ongoing BB therapy at the time of admission. A Poisson regression model with robust standard errors of variance was used, while adjusting for confounders, to evaluate the association between BB therapy, RCRI, and 30-day mortality. RESULTS: A total of 126,934 cases met the study inclusion criteria. Beta-blocker therapy was associated with a 65% decrease in the risk of 30-day postoperative mortality in the whole study population [adj. IRR (95% CI): 0.35 (0.32-0.38), p < 0.001]. The use of BB also resulted in a significant reduction in 30-day postoperative mortality within all RCRI cohorts. However, the most pronounced effect of beta-blocker therapy was seen in patients with an RCRI score greater than 0. CONCLUSIONS: Beta-blocker therapy is associated with a reduction in 30-day postoperative mortality, irrespective of RCRI score. Furthermore, patients with an elevated cardiac risk appear to have a greater benefit of beta-blocker therapy. LEVEL OF EVIDENCE: Level II, Therapeutic / Care Management.