This systematic review and meta-analysis will provide the first evidence synthesis on whether the specialty of the endoscopist is associated with colonoscopy quality metrics and/or outcomes. Given the established inter-endoscopist quality variations seen with colonoscopy, the results of this study are likely to guide aspects of training, maintenance of certification, credentialing, and quality assurance going forward.
The field of colonoscopy quality is relatively well established, with a number of gastroenterology societies world-wide having endorsed minimum and aspirational benchmarks for several quality indicators and outcomes [23, 24]. These benchmarks were designed based on available evidence at the time and are intended to reduce endoscopist-level variation and consequently improve patient outcomes. However, significant variation persists in the quality of colonoscopy, an integral procedure in the overall effort to screen for and reduce the burden of CRC [3]. Thus, our study represents an important piece of the puzzle in terms of determining potential endoscopist level factors that are associated with quality metrics and outcomes.
Though our study protocol was designed to mitigate potential biases, our study will nevertheless have limitations. Firstly, given our experience performing meta-analysis on endoscopist factors in colonoscopy [9], we anticipate that several studies will not report potentially relevant confounding variables such as endoscopist age, cumulative experience, procedural volumes, procedural indications, doses of sedating medication, or bowel preparation scores. Furthermore, even if studies do report potential confounders, it is anticipated that most studies assessing our topic of interest will report these data at the study level (rather than at the endoscopist level). Thus, the results of any potential subgroup analyses or meta-regression analyses could be misleading given the potential for ecological bias [25]. Additionally, there may be an element of selection bias within each study, whereby surgeons could conceivably have different case mixes than gastroenterologists; this could conceivably bias the results in favour of one group or another when one considers quality indicators such as ADR or adverse event outcomes such as perforation. To mitigate against this risk, we have set strict a priori criteria that define included study samples as primarily screening populations versus non-screening populations (Table 2).
In a broader context, we also anticipate that the relevance and actionability of our study findings will be questioned. Especially when one considers the shift toward competency-based medical education in general [26], and in endoscopic training in particular [27], the current comparisons between gastroenterologists, surgeons, and other endoscopists may become less relevant over time. However, we maintain that this topic is of urgent importance to the current landscape as it pertains to colonoscopy practice. Nevertheless, the practice of audit and feedback of quality metrics as well as educational interventions for independent colonoscopy practitioners are more relevant now than ever, having both been shown to be effective in improving colonoscopy quality [28, 29].
Overall, despite these limitations, we anticipate that our study will yield important information on endoscopist specialty and its association with colonoscopy quality indicators and outcomes. Our results have potential implications regarding not only direct patient care, but credentialing and training. Our study will summarize the existing state of evidence on this topic, and in so doing, will also serve to elucidate potential improvements for future studies assessing endoscopist level characteristics in the performance of colonoscopy.