Changes in rectus femoris diameter: a cooperation-independent assessment method for ICU-acquired weakness.

A major lower limb amputation (LLA), defined as an amputation performed at the ankle level or above, is a life-altering event with profound consequences at both individual and societal levels [, ]. This is particularly true for major LLAs resulting from dysvascular complications, which are primarily caused by peripheral vascular disease []. The prevalence of peripheral vascular disease and its associated complications, including dysvascular LLAs, is rising worldwide []. Globally, the majority of major LLAs result from dysvascular complications [–]. Large cohort studies have reported that approximately 96% of individuals with LLAs had peripheral arterial disease as the primary underlying etiology, followed by diabetes, itself a form of vascular disease [, ]. Major dysvascular LLAs impose a significant burden on healthcare systems worldwide due to the high cost of associated medical care. Studies across different healthcare systems have consistently demonstrated substantial economic burden, with initial hospitalization costs alone representing a significant portion of total healthcare expenditure, excluding physician compensation and follow-up costs [–]. Beyond the economic burden, major dysvascular LLAs are linked to poor clinical outcomes, including high rates of prolonged hospitalization, readmission, re-amputation, and mortality [, –]. International data indicate that patients undergoing major dysvascular LLAs have a median hospital stay of approximately 19 days, a 19 to 27% readmission rate within 30 days for subsequent amputations, and a 30-day mortality rate as high as 8% [, , –]. Another challenge for healthcare systems and clinical research involving people with dysvascular amputation is the variability in the reporting of outcome measures and indicators. Outcome measures refer to the tools and instruments used to assess the impact of an intervention or program over a defined period []. Outcome indicators, on the other hand, are measurable variables or attributes that capture and reflect the clinical parameters under evaluation []. A notable lack of consensus exists internationally regarding both program and patient-reported outcomes in amputee rehabilitation services, with many programs across different healthcare systems relying on informal, non-standardized outcome measures [–]. This lack of consensus compromises patient care quality and rehabilitation outcomes, while also limiting the ability to compare outcomes between different healthcare services internationally to identify more effective care models and clinical pathways for the LLA population []. Moreover, this lack of consensus limits the feasibility of conducting evidence-based syntheses, such as systematic reviews and meta-analyses, which impedes the development of standardized clinical practice guidelines and reduces the utility of research findings for informing clinical decision-making and patient care [, ]. Core outcome sets (COS) may help address these issues, by allowing relevant stakeholders to collaborate and reach a consensus on the key outcome measures and indicators that should be measured and reported in all clinical trials related to a specific health condition []. The first step in developing a condition-specific COS is to conduct a systematic review of the existing literature to identify and categorize outcome measures and indicators reported in previous studies. This ensures that the development process is grounded in current evidence and helps inform subsequent phases, including qualitative data collection to capture perspectives from patients and healthcare professionals, and the use of a Delphi survey to establish consensus on the COS [].