1B-06 - COVID-19 increases the risk of hip fractures in older subjects – a register-based Swedish population study

Background: Hip fractures are a major public health concern with high incidence in Sweden. Some evidence has indicated that COVID-19 infection may increase fracture risk via biological mechanisms (e.g., systemic inflammation, reduced mobility) or indirect pathways (e.g., increased frailty, delayed care).

Objectives: To determine if COVID-19 infection is associated with increased hip fracture risk in Swedish adults aged ≥50, while accounting for demographic, clinical, and socioeconomic covariates.

Methods: This nationwide population-based cohort study utilized data from the SCIFI-PEARL project, which links multiple registers covering the entire Swedish population since 2015. In this study, residents aged ≥50 years on 2020-01-01 were included and followed until the end of 2022. Exposure was the first COVID-19 infection, treated as a time-varying variable. The primary outcome was an incident hip fracture 6 months post-COVID, while secondary outcomes included incident proximal humerus fracture and wrist fractures. Statistical analysis involved Cox proportional hazards models with time-varying exposure. Models were adjusted for age, sex, marital status, education, employment, socioeconomic status, frailty (Hospital Frailty Risk Score), comorbidities, prior medication use, and COVID-19 vaccination status (time-varying). Sensitivity analyses examined 12- and 24-month post-COVID-19 risk windows for hip fractures.

Results: Among 3 931 893 individuals included, 50 883 incident hip fractures were identified. COVID-19 infection was associated with a statistically significant 43% increased risk of hip fracture (hazard ratio 1.43, 95% confidence interval 1.36–1.50) in fully adjusted models. The increased risk was more pronounced in men (1.57, 1.45–1.71) than women (1.36, 1.28–1.45), and was primarily seen among adults aged ≥65 years (men≥65: 1.68, 1.54–1.82; women≥65: 1.42, 1.33–1.51), whereas the effect among 50-64 yeas were weaker (men 50-64: 1.02, 0.79–1.33; women 50-64: 0.94, 0.74–1.19). Associations with wrist and proximal humerus fractures were weaker and not statistically significant. Sensitivity analyses using 12- and 24-month post-COVID-19 exposure windows demonstrated that hip fracture risks attenuated over time.

Conclusions: COVID-19 is associated with a marked increase in hip fracture risk, particularly among older adults, highlighting the need for targeted prevention strategies in post-COVID care. The sex- and age-specific differences underscore the importance of surveillance in high-risk populations. These findings emphasize the importance of integrating fracture risk assessment into post-acute COVID-19 management to mitigate long-term morbidity and mortality.