CT-derived body composition as a predictor of supervised exercise therapy response in intermittent claudication and peripheral arterial disease: COMPOSE-PAD study protocol

Peripheral arterial disease (PAD) commonly presents with intermittent claudication, for which supervised exercise therapy (SET) is recommended as first-line treatment; however, real-world SET non-completion is frequent and a clinically relevant subgroup of patients fails to achieve meaningful functional improvement. No validated pre-treatment tool currently identifies these likely non-responders. This protocol describes a prospective single-centre observational cohort study designed to determine whether body composition derived opportunistically from routine computed tomography angiography (CTA) at the third lumbar vertebral level (L3), specifically skeletal muscle density and visceral adipose tissue (VAT) area, independently predicts 3-month SET outcome in patients with Fontaine IIa-IIb intermittent claudication. A total of 128 consecutive patients will be enrolled at the Complex Cardiovascular Centre, Hospital AGEL Trinec-Podlesi, Czech Republic. The primary composite outcome is treatment success at 3 months, defined as both functional improvement on standardised treadmill testing, expressed as an absolute increase of at least 50 m or a relative increase of at least 50% in maximum walking distance (MWD), and freedom from revascularisation. Treatment failure includes SET non-completion, functional non-response among programme completers, or revascularisation during follow-up irrespective of functional result. Associations between skeletal muscle density, VAT area, and treatment outcome will be examined using prespecified multivariable logistic regression adjusted for age, sex, and baseline MWD, with bootstrap internal validation. As this is a study protocol, no outcome data are yet available; enrolment is planned to begin in June 2026. This study will assess whether zero-burden metabolic phenotyping from routine CTA can help identify patients less likely to benefit from conservative management alone, but any derived model will require external multicentre validation before clinical use. ClinicalTrials.gov: NCT07433309.