Development and Validation of ViSarco: A Pragmatic Screening Tool for Sarcopenia in Primary Care

Sarcopenia remains underdiagnosed in Vietnam due to the absence of simple, reliable screening instruments tailored to primary‐care settings, so we developed ViSarco to facilitate early identification of sarcopenia among community‐dwelling older adults; using a six‐phase exploratory mixed‐methods design, we generated candidate items through a comprehensive literature review and in‑depth interviews with 37 frontline healthcare providers, then conducted a cross‑sectional study of 416 adults aged ≥60 years applying AWGS 2019 criteria and logistic regression to assign scores of 2 for body‐mass index, 1 for arm circumference and 1 for calf circumference; we validated ViSarco in an independent cohort of 806 older adults and benchmarked its performance against six established international tools, finding that at a cut‑off score ≥2 it achieved 77.2% sensitivity, 76.6% specificity and an AUC of 0.77 in the derivation sample and maintained 78% overall accuracy with an AUC of 0.83 on external validation, outperforming all comparators; these results demonstrate that ViSarco is a brief, feasible and high‐performing screening tool well suited to resource‐limited primary‐care environments, offering robust diagnostic capability to support timely case finding and intervention for sarcopenia in older Vietnamese populations.