Keep it simple: colonoscopies ‘non compliant’ with complex new guidelines

Clinicians are regularly failing to comply with surveillance colonoscopy guidelines because the most recent update is likely too complicated, researchers are arguing.

The message follows an audit of colonoscopy waitlists at two South Australian hospitals in 2020 and early 2021, which found only 51% of patients fell within the recommended intervals for polyp surveillance based on the 2018 guidelines issued by the NHMRC.

The research team also examined how many patients would have been eligible for surveillance colonoscopy based on the previous version of guidelines released in 2011 – finding a far higher compliance rate of 66%.

This dramatic fall in compliance rates was “possibly due to the increased complexity” of the updated guidelines, they wrote in ANZ Journal of Surgery.

They stressed the updated guidelines – which ran to more than 43 pages – should theoretically have skewed towards more 10-year screening intervals, rather than the three- or five-year intervals frequently endorsed under the earlier version.

“However, when differences in compliance rates were accounted for, there were in fact more actual bookings for 1 year using the 2018 guidelines, and fewer 10-year intervals booked,” the researchers said.

“When this was projected forward to five and 10 years using a hypothetical group of 100 patients, it is predicted that this would result in an additional 50 colonoscopies added to the waitlist at five years and 86 colonoscopies at 10 years for every 100 patients that had a polyp surveillance colonoscopy.”

Overall compliance was significantly poorer for both low and high-risk adenomas under the new guidelines, they added, a finding that was consistent with previous studies where these patients were more likely to receive earlier follow-up.

They noted the two hospitals, both major tertiary institutions, had different approaches to assessing and allocating colonoscopy surveillance intervals, with one using a dedicated nurse coordinator reviewing patient case notes and pathology before recommending colonoscopy intervals based on the guidelines.

By contrast, interval recommendations at the other hospital were “made by the clinician based on colonoscopy findings and histopathology which may be open to variability in interpretation particularly for ambiguous cases”, the researchers said.

“Additionally, 7% of colonoscopies were unwarranted when compared to the 2018 guidelines, putting patients at unnecessary risks,” they wrote.

“This was particularly evident in patients aged over 75, where the Charleson Comorbidity Index (CCI) predicted high 10-year morbidity.”

The researchers said it had been hoped the updated guidelines would have reversed Australia’s earlier growth in surveillance colonoscopies, which had reached above 600,000 annually by 2017.

“However, due to worse compliance with the current 2018 guidelines, more procedures are being booked,” they wrote.

“The rapidly compounding effect of this may contribute to the increasing colonoscopy burden and service variation, currently reflected in extended waitlists for public hospital procedures, significant financial cost and patient impact which is an area of attention across all jurisdictions.”

“The patient population of low- and high-risk adenomas are impacted most by inappropriate surveillance intervals as they represent more than 75% of cases in the current study.”

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