Methods <p>The study design was a matched cohort study based on prospectively collected registry data from the Danish National Patient Register. Included were all patients presenting with an FNF in the Northern Region of Denmark between 2018 and December 2023. The matched reference population was established with a 1:10 ratio (for each patient with an FNF, we included ten citizens who had not experienced an FNF prior to the inclusion date). Basic characteristics including age, gender, and individual comorbidity status were obtained from all patients and the matched population.</p> Results <p>A total of 3246 patients were identified with an FNF during the 6-year study period (mean follow-up 2.6 years). Patients’ mean age at the time of fracture was 77.9 (95% CI 77.4–78.4). Male mean age was 74.9 years (95% CI 73.9–75.9). Female mean age was 79.6 years (95% CI 79.1–80.2). Gender distribution was 64% females and 36% males. A total of 761 (23.4%) patients died during the first 12 months after the fracture. Within the first 30 days after fracture, patients with FNFs demonstrated markedly increased mortality compared with the age-, sex-, and comorbidity-matched reference cohort, with a crude 30-day mortality of 10% versus 0.3% and a hazard ratio of 16.1. Cumulative survival curves showed that patients with FNFs had an elevated mortality risk during the first 4 years following fracture, after which survival became nearly comparable between the fracture and matched cohorts.</p> Conclusion <p>This study demonstrated that FNFs are associated with a markedly elevated short-term mortality risk, with patients experiencing a 16 times higher risk of death within 30 days compared with an age-, gender-, and comorbidity-matched group without an FNF. The excess risk was most pronounced during the first 3–6 months and persisted for up to 4 years before converging with the match group mortality rates.</p>