C0209 - A Cost Utility Model Supports Changes in Post-Treatment Surveillance Associated With the 2022 American College of Gastroenterology Guidelines

Monday, October 24, 2022

3:00 PM – 5:00 PM ET

Location: Crown Ballroom

Presenting Author(s)

Cary C. Cotton, MD, MPH

University of North Carolina
Chapel Hill, NC

Cary C. Cotton, MD, MPH¹, Swathi Eluri, MD, MSCR², Meera Parikh, BS², Susan Moist, MPH², Ariel Watts, BS², Nicholas J. Shaheen, MD, MPH¹
¹University of North Carolina, Chapel Hill, NC; ²University of North Carolina School of Medicine, Chapel Hill, NC

Introduction: Radiofrequency ablation is a safe and effective treatment for neoplastic Barrett’s esophagus (BE), but surveillance after endoscopic eradication has only been studied observationally without any studies of this disease’s natural history. Recent natural history modeling work has allowed qualified estimation of a natural history scenario. We sought to apply our multi-state model of post-ablation natural history to study the cost effectiveness of surveillance after endoscopic eradication of neoplastic BE.

Methods: We constructed a microsimulation cost-utility model of endoscopic surveillance after complete eradication of intestinal metaplasia (CEIM) with intervals as recommended by the 2022 American College of Gastroenterology BE guideline. A cohort of participants were modeled after the United States (US) Radiofrequency Ablation cohort in terms of demographics, worst prior histologic grade, and pre-treatment BE segment length. Transition probabilities for the natural history were estimates from published multi-state models. The model was Markov generalized to allow differing rates of progression based on BE characteristics as covariates to the multi-state model and for other-cause mortality to depend on age. There were states for: no recurrence, recurrence with various histologic grades, ablative re-treatment, endoscopic mucosal resection, invasive adenocarcinoma, and death. We considered a willingness-to-pay threshold of 100,000 2017 US dollars ($) per quality-adjusted life year (QALY). Model parameters and their sources are described in the Table.

Results: In the base case scenario of the model, surveillance and re-treatment decreased progression to invasive esophageal adenocarcinoma at ten years by 1.2% in LGD and 13.0% in HGD/IMC (Figure). Compared to the natural history scenario, the incremental cost effectiveness ratio for surveillance at ten years was $79,125 for LGD and $10,952 for HGD/IMC.

Discussion: In the base case scenario of this cost-utility model, newly recommended surveillance intervals were highly cost effective for HGD/IMC and approached the margins of cost-effectiveness for LGD in a microsimulation cost-utility model. This supports the new guideline recommendation to decrease the frequency of post-treatment surveillance of HGD/IMC and LGD. While development of the model requires probabilistic sensitivity analysis and calibration, the model has the potential to inform the health economics of clinical processes after CEIM.

Figure: Model state occupancy by months after complete eradication of intestinal metaplasia.

Model variable	Base case value	Reference/details
Structural model assumptions
Model cycle length	3 months
Model time horizon	10 years
Model starting year	2017	For other-cause mortality and inflation adjustment
Other cause mortality	Population	2020 Social Security actuarial cohort life tables
Time for resection	1 cycle	Resection for all recurrent HGD or IMC
Resection success rate	100%	Simplifying assumption
Time for ablation	1 cycle	Repeated until successful
Discounting of costs/utilities	3%	Per year
Probabilities per cycle from the literature
Death from invasive adenocarcinoma	7.63%	SEER 5-Year Relative Survival Rates 2012-2018*
Complete eradication of intestinal metaplasia after recurrence	57.7%	Guthikonda et al., The American Journal of Gastroenterology, 2017
Cancer progression from recurrence	0.1625%	Guthikonda et al., The American Journal of Gastroenterology, 2017
Utilities per cycle from the literature
Surveillance after CEIM	97%	Boger et al., Alimentary Pharmacology and Therapeutics, 2010
Retreatment endoscopy	94%	Boger et al., Alimentary Pharmacology and Therapeutics, 2010
Esophageal adenocarcinoma	96%	Boger et al., Alimentary Pharmacology and Therapeutics, 2010
Costs per cycle from the literature
Surveillance endoscopy	$1,019	Inadomi et al., Gastroenterology, 2009†
Cost of cancer care	$13,532	Inadomi et al., Gastroenterology, 2009†
Cost of ablation re-treatment	$4,317	Inadomi et al., Gastroenterology, 2009† Assumed half cost of initial treatment
Cost of resection re-treatment	$934	Filby et al., Journal of Comparative Effectiveness Research, 2017**
Assumes cumulative incidence = 1 – e^(-incidence x time), †Assuming 17.7% inflation, *Assumes 133% exchange rate with the British Pound.

Table: Microsimulation model parameters in the base case scenario and their sources.

Disclosures:

Cary Cotton indicated no relevant financial relationships.

Swathi Eluri indicated no relevant financial relationships.

Meera Parikh indicated no relevant financial relationships.

Susan Moist indicated no relevant financial relationships.

Ariel Watts indicated no relevant financial relationships.

Nicholas Shaheen indicated no relevant financial relationships.

Cary C. Cotton, MD, MPH¹, Swathi Eluri, MD, MSCR², Meera Parikh, BS², Susan Moist, MPH², Ariel Watts, BS², Nicholas J. Shaheen, MD, MPH¹. C0209 - A Cost Utility Model Supports Changes in Post-Treatment Surveillance Associated With the 2022 American College of Gastroenterology Guidelines, ACG 2022 Annual Scientific Meeting Abstracts. Charlotte, NC: American College of Gastroenterology.