Vaccination against COVID-19 reduced the mortality risk of COVID-positive hip fracture patients to baseline levels: the nationwide data-linked IMPACT Protect study

Summary
This nationwide study used data-linked records to assess the effect of COVID-19 vaccination among hip fracture patients. Vaccination was associated with a lower risk of contracting COVID-19 and, among COVID-positive patients, it reduced the mortality risk to that of COVID-negative patients. This provides essential data for future communicable disease outbreaks.

Purpose
COVID-19 confers a three-fold increased mortality risk among hip fracture patients. The aims were to investigate whether vaccination was associated with: i) lower mortality risk, and ii) lower likelihood of contracting COVID-19 within 30 days of fracture.

Methods
This nationwide cohort study included all patients aged > 50 years that sustained a hip fracture in Scotland between 01/03/20–31/12/21. Data from the Scottish Hip Fracture Audit were collected and included: demographics, injury and management variables, discharge destination, and 30-day mortality status. These variables were linked to government-managed population level records of COVID-19 vaccination and laboratory testing.

Results
There were 13,345 patients with a median age of 82.0 years (IQR 74.0–88.0), and 9329/13345 (69.9%) were female. Of 3022/13345 (22.6%) patients diagnosed with COVID-19, 606/13345 (4.5%) were COVID-positive within 30 days of fracture. Multivariable logistic regression demonstrated that vaccinated patients were less likely to be COVID-positive (odds ratio (OR) 0.41, 95% confidence interval (CI) 0.34–0.48, p < 0.001) than unvaccinated patients. 30-day mortality rate was higher for COVID-positive than COVID-negative patients (15.8% vs 7.9%, p < 0.001). Controlling for confounders (age, sex, comorbidity, deprivation, pre-fracture residence), unvaccinated patients with COVID-19 had a greater mortality risk than COVID-negative patients (OR 2.77, CI 2.12–3.62, p < 0.001), but vaccinated COVID19-positive patients were not at increased risk of death (OR 0.93, CI 0.53–1.60, p = 0.783).

Conclusion
Vaccination was associated with lower COVID-19 infection risk. Vaccinated COVID-positive patients had a similar mortality risk to COVID-negative patients, suggesting a reduced severity of infection. This study demonstrates the efficacy of vaccination in this vulnerable patient group, and presents data that will be valid in the management of future outbreaks.