The impact of body roundness index (BRI) on obstructive sleep apnea (OSA) severity: an exploratory sequential...

Screening for obstructive sleep apnea (OSA) in primary care is hindered by the lack of readily available, pathophysiologically informed tools. The Body Roundness Index (BRI), a novel metric reflecting central obesity, has unclear clinical applicability and efficacy boundaries, particularly in explaining the paradox of "high BRI without severe OSA."

We employed an explanatory sequential mixed-methods design. In Phase I, ordered logistic regression and ROC analysis quantified the association and diagnostic value of BRI with OSA severity in 2,596 suspected OSA patients. In Phase II, semi-structured interviews and thematic analysis explored disease attribution and behavioral coping in 25 patients categorized into a "Contradictory Group" (high BRI, non-severe OSA; n = 8) and a "Typical Group" (high BRI, severe OSA; n = 17).

BRI was an independent predictor of OSA severity (OR = 1.238, 95% CI: 1.159-1.322, P < 0.001). Its diagnostic performance for severe OSA (AUC = 0.668) was comparable to BMI (AUC = 0.674) but inferior to neck circumference (AUC = 0.711). Efficacy was higher in males (AUC = 0.645) but limited for mild-to-moderate OSA (AUC = 0.532 and 0.490 for mild and moderate groups, respectively). Qualitatively, the Contradictory Group systematically attributed symptoms to localized structural issues, complex comorbidities, or physiological events rather than systemic obesity, forming a disease perception model distinct from the typical "obesity-obstruction" paradigm.

While BRI provides a pathophysiologically grounded alternative to BMI for severe OSA risk assessment, combining BRI, BMI, and neck circumference offers modest incremental diagnostic value. We advocate shifting OSA screening toward a stepwise, patient-centered pathway that prioritizes neck circumference and systematically integrates multidimensional clinical characteristics and health beliefs.