Recruitment into randomised trials of arteriovenous grafts: A systematic review

Abstract

Although randomised controlled trials (RCT) are considered the optimal form of evidence, there are relatively few in surgery. Surgical RCT are particularly likely to be discontinued with poor recruitment cited as a leading reason. Surgical RCT present challenges over and above those seen in drug trials as the treatment under study may vary between procedures, between surgeons in one unit, and between units in multi-centred RCT. The most contentious and debated area of vascular access remains the role of arteriovenous grafts, and thus the quality of the data that is used to support opinions, guidelines and recommendations is critical. The aim of this review was to determine the extent of variation in the planning and recruitment in all RCT involving AVG. The findings of this are stark: there have been only 31 RCT performed in 31 years, the vast majority of which exhibited major limitations severe enough to undermine the results. This underlines the need for better quality RCT and data, and further inform the design of future studies. Perhaps most fundamental is the planning for a RCT that accounts for the intended population, the uptake of a RCT and the attrition for the significant co-morbidity in this population.

Challenges to Performance of Clinical Trials on Vascular Access

“…The differences highlighted between BEST-CLI HPSs and LPSs are widely applicable to vascular access studies, which typically involve numerous sites of varying recruitment levels. 5 In addition to the potential for hindering enrollment of patients, such significant interinvestigator differences can lead to criticism that there is a threat to internal validity because the HPS and LPS patients may be systematically different and the treatments also be systematically different. Careful selection of trial sites can help mitigate this concern.…”

“…Such low awareness manifests in 25 recent RCTs recruiting at a mean of 80 patients total per study, with trials having to end because of recruitment as low as 0.18 patient recruited per center per month. 5 …”

“…To fairly compare these approaches, both observational trials 3 and randomized control trials (RCTs) have been conducted. 4,5 RCTs and meta-analyses of several RCTs provide the highest level of evidence to evaluate a particular therapy, largely because of the belief that these designs can reduce, if not eliminate, investigator bias. 6 When conducting a meta-analysis, authors may include lowpower studies, creating heterogeneity in the analysis.…”

“…To fairly compare these approaches, both observational trials 3 and randomized control trials (RCTs) have been conducted. 4 , 5 …”