Clinical tools to assess functional capacity during risk assessment before elective noncardiac surgery : a scoping review

Background: Functional capacity is critical to preoperative risk assessment, yet guidance on its measurement in clinical practice remains lacking. Purpose: To identify functional capacity assessment tools studied before surgery and characterize the extent of evidence regarding performance, including in populations where assessment is confounded by noncardiopulmonary reasons. Data sources: MEDLINE, EMBASE, and EBM Reviews (until July 2024). Study selection: Studies evaluating performance of functional capacity assessment tools administered before elective noncardiac surgery to stratify risk for postoperative outcomes. Data extraction: Study details, measurement properties, pragmatic qualities, and/or clinical utility metrics. Data synthesis: 6 categories of performance-based tests and 5 approaches using patient-reported exercise tolerance were identified. Cardiopulmonary exercise testing (CPET) was the most studied tool (132 studies, 32 662 patients) followed by field walking tests (58 studies, 9393 patients) among performance-based tests. Among patient-reported assessments, the Duke Activity Status Index (14 studies, 3303 patients) and unstructured assessments (19 studies, 28 520 patients) were most researched. Most evidence focused on predictive validity (92% of studies), specifically accuracy in predicting cardiorespiratory complications. Several tools lacked evidence on reliability (test consistency across similar measurements), pragmatic qualities (feasibility of implementation), or concurrent criterion validity (correlation to gold standard). Only CPET had evidence on clinical utility (whether administration improved postoperative outcomes). Older adults (=65 years) were well represented across studies, whereas there were minimal data in patients with obesity, lower-limb arthritis, and disability. Limitation: Synthesis focused on reported data without requesting missing information. Conclusion: Though several tools for preoperative functional capacity assessment have been studied, research has overwhelmingly focused on CPET and only 1 aspect of validity (predictive validity). Important evidence gaps remain among vulnerable populations with obesity, arthritis, and physical disability. Primary funding source: None. (Open Science Framework: https://osf.io/ah7u5).