Osteosarcopenia as a Risk Factor for Atrial Fibrillation: A Multi-Cohort Study.

BACKGROUND: Osteosarcopenia, characterized by concurrent reductions in skeletal muscle mass and bone mineral density, is an emerging geriatric syndrome. Although sarcopenia and osteoporosis have been individually linked to atrial fibrillation (AF), the association between osteosarcopenia and incident AF remains unclear. OBJECTIVES: The authors aimed to investigate the association between osteosarcopenia and incident AF and to evaluate its incremental prognostic value beyond established AF risk factors. METHODS: In this prospective cohort study using the UK Biobank, participants without previous AF were included at baseline. A replication analysis was conducted in the H-PEACE (Health and Prevention Enhancement) cohort. Participants were categorized into 4 groups: reference, sarcopenia alone, osteoporosis alone, and osteosarcopenia. The primary endpoint was incident AF during a median follow-up of 13.8 [13.1;14.6] years. Multivariable Cox regression and risk prediction analyses were performed. RESULTS: Among 482,137 participants (mean age 56.4 ± 8.1 years; 45.2% male), osteosarcopenia was present in 0.65%. In the fully adjusted 4-group model, osteoporosis (adjusted HR [aHR]: 1.18; 95% CI: 1.03-1.36) and, most strongly, osteosarcopenia (aHR 1.33; 95% CI 1.09-1.62) were independently associated with incident AF, whereas sarcopenia alone was not (aHR: 1.05; 95% CI: 0.99-1.10). These findings were consistent in the H-PEACE cohort (adjusted OR: 2.10; 95% CI: 1.06-4.13; P = 0.032). CONCLUSIONS: Osteosarcopenia was independently associated with incident AF and provided incremental prognostic information beyond traditional risk factors, although the improvement in discrimination was limited. These findings support tailored AF screening in patients with osteosarcopenia to facilitate earlier diagnosis and treatment.