Outcome Heterogeneity in Prehabilitation TrialsdAre We Comparing Apples and Oranges?

Introduction: Over the last decade, the number of prehabilitation randomised controlled trials (RCTs) has increased significantly. Therefore, this review aimed to describe the outcomes reported in prehabilitation RCTs in patients undergoing cancer surgery. Methods: A search was conducted in Embase, Allied and Complementary Medicine Database, The Cochrane Library, PsycINFO, MEDLINE, and Cumulated Index to Nursing and Allied Health Literature from inception to July 2021. We included RCTs evaluating the effectiveness of preoperative exercise, nutrition, and psychological interventions on postoperative complications and length of hospital stay in adult oncology patients who underwent thoracic and gastrointestinal cancer surgery. The verbatim outcomes reported in each article were extracted, and each outcome was assessed to determine whether it was defined and measured using a validated tool. Verbatim outcomes were grouped into standardized outcomes and categorized into domains. The quality of outcome reporting in each identified article was assessed using the Harman tool (score range 0-6, where 0 indicated the poorest quality). Results: A total of 74 RCTs were included, from which 601 verbatim outcomes were extracted. Only 110 (18.3%) of the verbatim outcomes were defined and 270 (44.9%) were labeled as either "primary" or "secondary" outcomes. Verbatim outcomes were categorized into 119 standardized outcomes and assigned into one of five domains (patient -reported outcomes, surgical outcomes, physical/functional outcomes, disease activity, and intervention delivery). Surgical outcomes were the most common outcomes reported (n = 71 trials, 95.9%). The overall quality of the reported outcomes was poor across trials (median score: 2.0 [IQR = 0.00-3.75]). Conclusions: Prehabilitation RCTs display considerable heterogeneity in outcome reporting, and low outcome reporting quality. The development of standardized core outcome sets may help improve article quality and enhance the clinical utility of prehabilitation following cancer surgery. 2024 Elsevier Inc. All rights reserved.