Reported outcomes in studies of intermittent claudication - first step toward a core outcome set: systematic review

This review aimed to compile an exhaustive list of all outcome measures and identify different characteristics of the outcomes reported in studies of intermittent claudication as the first step in developing a core outcome set for intermittent claudication.

Medline and Embase were searched for all studies including individuals with intermittent claudication and reporting ≥1 outcome from January 2015 to August 2024. Abstract, full text screening and data extraction were performed by two investigators independently. All reported outcome measures were extracted verbatim and categorized by Dodd's domains (Core Outcome Measures in Effectiveness Trials registration: COMIC Study, 1590; https://www.comet-initiative.org/Studies/Details/1590).

4985 studies were screened and 408 were included. A total of 541 unique outcomes across 25 Dodd's domains were identified. Ankle-brachial pressure index was the most frequently reported outcome. Among the 541 unique outcomes, 386 outcomes were only reported once. Only 38.9% of the studies exclusively included patients with intermittent claudication. Patient-reported outcomes were reported in 36.2% of studies. There were wide variations in the definition of commonly used outcome measures (for example, major adverse limb event and primary patency) across different studies.

There is substantial heterogeneity in reported outcomes in studies of intermittent claudication. Most reported outcomes are clinical/physiology oriented rather than patient centred. Development of a core outcome set for intermittent claudication is vital to improve and standardize reporting in future research.