Risk of pacemaker implantation after femur fracture in patients with and without a history syncope: a Danish nationwide registry-based follow-up study.

BACKGROUND It has previously been described that fall-associated injuries including fractures are commonly observed among patients with bradyarrhythmia. However, knowledge on the risk of pacemaker implantation after admission due to femur fracture from large population-based epidemiologic data is lacking. Therefore, we investigated the risk of pacemaker implantation following femur fracture in patients with and without a history of previous syncope. METHODS All patients with femur fracture between 2005-2017 were identified using the Danish Nationwide Patient Registry. Among these, patients already having a pacemaker were excluded. Primary outcome was one-year risk of pacemaker implantation and secondary outcome was one-year all-cause mortality. Multivariable logistic regression was used to obtain absolute and relative risks of the study endpoint in relation to patients with versus without history of syncope and standardized to the age, sex, selected comorbidity and pharmacotherapy distribution of all patients. RESULTS Of 93,093 patients with femur fracture, 5508 (5.9%) had a history of syncope within five years. Patients with prior syncope were slightly older (84 vs. 83 years), more often male (33.6% vs. 29.4%), and had more often comorbidities relative to those without history of syncope. All-cause mortality was significantly higher among those with previous history of syncope compared to those without previous syncope (29.9% vs. 28.6%, P = 0.021). The relative mortality risk was 1.05 (95% CI: 1.01-1.09, P = 0.021). A total of 695 (0.8%) patients underwent pacemaker implantation within 5 years following femur fracture, and a significantly higher proportion of patients with syncope had a pacemaker implanted within one year (1.6% vs. 0.7%, P < 0.001; relative risk, 2.01 [95% CI: 1.55-2.46]). CONCLUSIONS In patients with femur fracture, a history of syncope was significantly associated with a higher one-year risk of pacemaker implantation.