Current research mapping of respiratory sarcopenia: A scoping review

AIM: Respiratory sarcopenia is an emerging clinical concept characterized by the loss of respiratory muscle mass and function. However, the current research landscape, including clinical applications and diagnostic consensus regarding respiratory sarcopenia, remains fragmented. This scoping review aimed to map existing studies to clarify the target populations, diagnostic methods, clinical outcomes, and interventions for respiratory sarcopenia. METHODS: This scoping review followed the PRISMA-ScR guidelines and the Joanna Briggs Institute methodology. We searched major databases (MEDLINE, CENTRAL, CINAHL, and Web of Science) and clinical trial registries on January 31, 2026, for primary studies evaluating respiratory sarcopenia in adults. Data regarding study characteristics, diagnostic components, clinical outcomes, and treatments were extracted and synthesized descriptively. RESULTS: Twenty-one studies met the inclusion criteria and predominantly originated in Japan (n = 14). Studies largely targeted community-dwelling older adults and perioperative patients. Diagnostically, the vast majority evaluated "probable" respiratory sarcopenia, relying on systemic muscle mass as a surrogate, primarily via bioelectrical impedance analysis (n = 11) or prediction formula for appendicular skeletal muscle mass (n = 4). Peak expiratory flow rate (n = 11) and maximal inspiratory pressure (n = 10) were the most frequently used measures of respiratory muscle strength. Observational studies reported associations between this condition and adverse outcomes, including mortality and postoperative complications. No interventional trials were identified. CONCLUSIONS: Current evidence on respiratory sarcopenia is largely observational, geographically concentrated, and relies heavily on "probable" definitions. Establishing a standardized diagnostic measure for respiratory muscle mass may help clarify patient stratification and inform future trials.