Risk of falls, recurrent falls and osteoporotic fractures in SLE patients with comorbid fibromyalgia: a propensity score-matched cohort study using the TriNetX Network

OBJECTIVE: Fibromyalgia (FM) frequently co-occurs with SLE, but its independent contribution to musculoskeletal risk is unclear. We aimed to determine whether comorbid FM is independently associated with the risk of falls, recurrent falls, thoracolumbar vertebral fractures and osteoporotic fractures in patients with SLE. METHODS: We conducted a propensity score-matched (PSM) retrospective cohort study using the TriNetX US Collaborative Network. Adult SLE patients with comorbid FM (SLE+FM) were matched 1:1 to SLE patients without FM (SLE-only) on demographics, comorbidities, laboratory parameters and 19 medications. A 6 month washout period preceded outcome ascertainment to ensure capture of incident events only. Time-to-event analyses over 5 years for risk of falls, recurrent falls, thoracolumbar vertebral fractures and osteoporotic fractures used Kaplan-Meier curves and Cox proportional hazards regression. RESULTS: After 1:1 PSM, 23 775 matched pairs were retained with substantially improved covariate balance. At 5 years, SLE+FM patients had significantly elevated risks of incident falls (adjusted HR (aHR) 1.38, 95% CI 1.29 to 1.48), recurrent falls (aHR 1.53, 95% CI 1.32 to 1.76), thoracolumbar vertebral fractures (aHR 1.18, 95% CI 1.01 to 1.37) and osteoporotic fractures (aHR 1.14, 95% CI 1.02 to 1.27) compared with the SLE-only group. Associations were directionally consistent at 3 years and across all prespecified subgroups. Kaplan-Meier curves showed early and progressive divergence between cohorts from the start of follow-up. CONCLUSION: Comorbid FM is significantly and independently associated with increased fall and fracture risk in SLE. These findings support the incorporation of FM evaluation into fall risk assessment, alongside multidisciplinary bone-protective and fall-prevention strategies, in SLE patients with comorbid FM.