Visceral adiposity measured by Body Roundness Index linked to higher all-cause and cardiovascular mortality in osteoarthritis: Results from NHANES 1999 to 2018

Osteoarthritis (OA), a prevalent musculoskeletal condition, heightens physical disability and cardiovascular risks. While adiposity metrics are linked to adverse outcomes, the impact of Body Roundness Index (BRI) on mortality in OA patients remains unexplored. This study investigates the relationship between BRI and mortality outcomes in this population. A prospective analysis was conducted on 4540 OA patients from the National Health and Nutrition Examination Survey (1999-2018). BRI was calculated using standardized height and waist circumference measurements. Multivariate Cox proportional hazards models, adjusted for demographics, lifestyle, comorbidities, and medications, evaluated the association between BRI and mortality. Restricted cubic spline and piecewise regression analyses were used to assess nonlinear relationships. Over a median follow-up of 7.5 years, 1156 all-cause and 323 cardiovascular deaths were recorded. BRI exhibited a J-shaped nonlinear association with all-cause mortality, with a threshold at 4.40. Beyond this, every unit increase in BRI correlated with a 27% higher risk of all-cause mortality (hazard ratio: 1.27, 95% confidence interval: 1.15-1.39). Cardiovascular mortality showed a linear association with BRI (hazard ratio per unit: 1.33, 95% confidence interval: 1.14-1.57). Stratified analyses highlighted stronger associations in males, non-Hispanic Whites, and alcohol users (P-interaction < .05). BRI demonstrated a J-shaped relationship with all-cause mortality and a linear association with cardiovascular mortality in OA patients. These findings support BRI as a valuable risk stratification tool, emphasizing the need for optimal body composition in OA management.