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Conversion of colonoscopy to flexible sigmoidoscopy: an unintended consequence of quality measurement in endoscopy
  1. Chris Thompson1,
  2. Tariq Ismail1,
  3. Simon Radley1,
  4. Robert Walt2,
  5. Stephen Thomas Ward1
  1. 1Department of Colorectal Surgery, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
  2. 2Department of Gastroenterology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
  1. Correspondence to Stephen Thomas Ward, Department of Colorectal Surgery, University Hospital Birmingham, Mindelsohn Way, Birmingham B15 2TH, UK; Stephen.ward7{at}


Objective To quantify the proportion of requests for colonoscopy that are performed as flexible sigmoidoscopy and documented reasons for this in ordinary UK hospital practice. To determine the effect these requests have on colonoscopy completion rate if they are included in the denominator of the calculated rate by individual endoscopist.

Design Retrospective study of 22 months flexible sigmoidoscopy practice at a major UK teaching hospital. All flexible sigmoidoscopies performed had their associated request form examined.

Setting UK NHS University Hospital.

Patients All patients receiving outpatient flexible sigmoidoscopy from January 2013 to October 2014 with no exclusions.

Intervention Conversion of colonoscopy to flexible sigmoidoscopy.

Main outcome measures Conversion of colonoscopy to flexible sigmoidoscopy, reason for conversion and adjusted colonoscopy completion rate.

Results 71 of the 3526 flexible sigmoidoscopies performed (2.0%) were originally requested as colonoscopies, and therefore, represented conversions. Conversion reason was noted only in 26 (37%) of converted cases. Adjustment of colonoscopy completion rate to include conversions pushed four of our unit's 22 endoscopists below the UK national 90% standard.

Conclusions Conversion to flexible sigmoidoscopy occurs in 2% of patients originally booked for colonoscopy. The reason for this conversion is often unqualified and may be inappropriate. Conversion can affect the colonoscopy completion rate, and therefore, should be included in endoscopists’ overall performance statistics.


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