Impact of inappropriate indication to colonoscopy on waste production and potential benefit of an intervention. A multicenter prospective study

Aims Colonoscopy leads to production of an important amount of carbon dioxide (CO₂) quantified in 6.71 Kg CO₂e (direct emissions) and as high as 28 kg CO₂e (direct and indirect emissions). Aim of the present study was to quantify the impact of inappropriate indication to colonoscopy on waste production and the potential benefit of an intervention.

Methods This study is derived from a multicenter prospective observational study involving 9 institutions in Emilia-Romagna, which is an Italian region with more than 4 million inhabitants, including consecutive adult patients undergoing colonoscopy for clinical indication outside CRC screening organized programs with adequate bowel cleansing and complete examinations. In this study, a predictive model for CRC based on clinical patient-related variables and indication according to Italian RAO criteria was derived and validated. In the present study, we applied the model to the derivation cohort and performed projections on the CO₂e based on the number of inappropriate or low-risk colonoscopies which would be saved according to appropriateness criteria and our predictive model, respectively.

Results Overall, 2,546 patients (mean age 63+14 years, female sex 49.8%) were included. CRC was found in 74 (2.9%) cases. Inappropriate colonoscopies were 1,262 (49.6%) according to ASGE criteria and 1,007 (39.5%) according to EPAGE-II criteria. The predictive model based on patient age, performance of a colonoscopy in past 10 years, and indication to colonoscopy according to RAO criteria defined 1,370 (53.8%) patients as low-risk (i.e. CRC risk<1%). CRC was found in 24 (1.9%) and 24 (2.4%) inappropriate colonoscopies according to ASGE and EPAGE-II criteria, respectively, and in 8 (0.6%) low-risk patients according to the predictive model. Therefore, if we simulate that patients at low risk of CRC would not undergo colonoscopy in our cohort, we would spare 1,176 procedures leading to reduction of CO2e equal to 7,891 Kg CO₂e (direct footprint) and 32,928 Kg CO₂e (direct and indirect footprint). Sparing inappropriate colonoscopies according to ASGE and EPAGE-II criteria would lead to reduction of CO2e equal to 8,468 Kg and 6,757 Kg CO₂e (direct footprint) and 35,336 Kg and 28,196 Kg CO₂e (direct and indirect footprint), respectively.

Conclusions Inappropriate colonoscopies do have a relevant impact on CO₂ emissions. ASGE and EPAGE-II appropriateness criteria might help in reduce CO₂ emissions at a price of missing a relevant amount of patients with CRCs. A clinical predictive model based on clinical patient-related variables and indication according to Italian RAO criteria could substantially reduce CO₂e with a negligible CRC miss rate. [1] [2]

Publication History

Article published online:
15 April 2024

• References

• 1 Elli L, La Mura S, Rimondi A. et al. The carbon cost of inappropriate endoscopy. Gastrointest Endosc 2023; S0016-5107 (23) 02865-1
• 2 Lacroute J, Marcantoni J, Petitot S. et al. The carbon footprint of ambulatory gastrointestinal endoscopy. Endoscopy. 2023; 55 (10) 918-926