Re-investigation rate following colon capsule endoscopy stratified by faecal haemoglobin concentration in a screening...

Endoscopy units throughout the world have seen a substantial increase in colonoscopy activity. One way to keep patient waiting time acceptable could be to introduce alternative diagnostic modalities. Colon capsule endoscopy has been proven to have a high diagnostic accuracy, yet the re-investigation rates reported are too high. Faecal haemoglobin concentration may offer a valid measure for triaging patients between diagnostic modalities, due to its association with colonic pathology.

To investigate the re-investigation rate and risk classification in complete colon capsule endoscopies in a screening population stratified by faecal haemoglobin concentration.

Cross-sectional analyses of a data set derived from the intervention arm of a large randomised controlled trial, CareForColon2015, conducted in the Region of Southern Denmark between August 2020 and December 2022.

Complete colon capsule endoscopy investigations were identified, and the proportions of investigations leading to re-investigation by colonoscopy were calculated, stratified by faecal haemoglobin concentration. Further, the odds of re-investigation were estimated by logistic regression models and the odds of increased risk classification by ordinal regression models.

The re-investigation rate was 58.6% in 1413 complete colon capsule endoscopies out of 2030 procedures. There were no significant differences (p = 0.312) in re-investigation rates between faecal haemoglobin concentration subgroups with 58.2%, 61.1% and 62.7% in the groups of 100-249, 250-499 and >499 ng hb/mL buffer, respectively. The odds of referral for re-investigation did not differ significantly either. The odds of increased risk classification (i.e. higher than level one) was 1.17 (CI 95% 0.92; 1.49, p = 0.211) for concentrations between 250 and 499 ng hb/mL buffer, and 1.40 (CI 95% 1.12; 1.77, p = 0.003) for concentrations above 499 ng hb/mL buffer, compared to 100-249 ng hb/mL buffer.

Faecal haemoglobin concentration did not prove to be a stand-alone selection parameter for diagnostic modality in a faecal immunochemical test-positive colorectal cancer screening population, although it was significantly associated with an increased risk classification.