Dear Sir,
We note with interest your comments concerning the Gruss et al.Citation1 budget impact model. We acknowledge that, as with all budget impact models and publications, there are areas where presentation of more detailed data would be desirable. However, we believe that our paper follows the principles of the ISPOR task force recommendationsCitation2, which were used as a guide in the development of our budget impact model.
The ISPOR task force recommendations state that the purpose of budget impact assessments is not to produce exact estimates of the budget consequences of an intervention but rather to provide a framework to allow users to understand the relationship between their practice and circumstances and the possible consequences of a new health technology. As such, our budget impact model clearly identifies the main cost driver to be the cost of colonoscopy, rather than the cleansing agents used.
Additionally, the ISPOR task force recommendations specifically include the recommendation to consider the use of real life data in addition to the use of published randomized controlled comparative clinical trial data. As part of the UK Joint Advisory Group on Gastroenterology recommendations, such user and unit colonoscopy audit data is routinely collected. The extent to which the data quoted is consistent with other units lies outside the scope of this piece of work. However, the disparity between inpatient and outpatient repeat rates is widely acknowledged. With respect to your concerns about relative efficacy, we would like to draw your attention to a recent independent publication presented at the Digestive Disorders Federation Meeting, LiverpoolCitation3, which demonstrates in a screening population that PEG+ASC is statistically more effective than Picolax as a bowel preparation for screening colonoscopy.
Whilst the points raised highlight weakness inherent in any budget impact approach, we do not believe that they undermine the conclusion that the main cost driver is the cost of colonoscopy, rather than the cleansing agents used, which is in-line with other authors’ reported observationsCitation4,Citation5.
References
- Gruss H-J, Cockett A, Leicester RJ. Budget-impact model for colonoscopy cost calculation and comparison between 2 litre PEG + ASC and sodium picosulphate with magnesium citrate sodium phosphate oral bowel cleansing agents. J Med Econ 2012;15:758-65
- Mauskopf, JA, Sullivan SD, Annemans L, et al. Principles of good practice for budget impact analysis: Report of the ISPOR Task Force on Good Research Practices—Budget Impact Analysis. Value Health 2007;10:336-47
- Howells E. Moviprep vs Picolax for screening colonoscopy. Gut 2012;61:A161-2
- Rex DK, Imperiale, TF, Latinovich DR, et al. Impact of bowel preparation on efficiency and cost of colonoscopy. Am J Gastroenterol 2002;97:1696-700
- Rex DR, Petrini JL, Baron TH, et al. Quality indicators for colonoscopy. Am J Gastroenterol 2006;101:873-85