Varying efficacy of Helicobacter pylori eradication regimens: cost effectiveness study using a decision analysis model

British Medical Journal, May 30, 1998 by A.E. Duggan, K. Tolley, C.J. Hawkey, R.F.A. Logan

In model 2 using the confirmatory [13]C-urea breath test no single variable in the sensitivity analysis substantially changed the comparative dominance of the two stage strategy of omeprazole, clarithromycin, and metronidazole. Only one combination of variables--that representing the least favourable efficacy and cost scenario for the regimen of omeprazole, clarithromycin, and metronidazole (89%, 40.00 [pounds sterling] per patient)--greatly altered the difference between the cost effectiveness of the strategies. This produced an estimate of over 50 years for the cost of a strategy of omeprazole, amoxycillin, and metronidazole then omeprazole, clarithromycin, and metronidazole and maintenance treatment to exceed the incremental costs of a strategy of omeprazole, clarithromycin, and metronidazole then omeprazole, clarithromycin, and metronidazole (17.8 years not discounted). Increasing the cost of maintenance treatment for ulcers improved the comparative cost effectiveness in favour of the more effective eradication strategies. The initial cost savings associated with the strategy of omeprazole, amoxycillin, and metronidazole then omeprazole, clarithromycin, and metronidazole comparative to the two stage strategy of omeprazole, clarithromycin, and metronidazole would be lost within a short time (1.5 years) and would make it difficult to justify its preference.

Discussion

It is now well established that eradication treatment for H pylori is more cost effective than either treatment for recurrent ulcers or maintenance treatment for duodenal ulcer disease.[4, 5] However, the comparative cost effectiveness of various regimens for eradicating H pylori is not clear. A clinical trial to evaluate this would be difficult as it requires a large number of patients and long and detailed follow up. Decision analysis models therefore provide useful information and guidance in situations where trial data is unavailable or difficult to obtain.

The variables used in this model are consistent with the findings of randomised comparisons of regimens of omeprazole, clarithromycin, and metronidazole and omeprazole, amoxycillin, and metronidazole, and of another review of trials of H pylori eradication.[1, 2] If anything these studies have found slightly larger differences in the efficacy of these two regimens than we have applied in our models. The magnitude of the difference in cost effectiveness of the regimens we have tested may therefore be greater.

Using the variables chosen, we have shown that from the prescriber's perspective even small differences in efficacy of these highly effective antibiotic regimens result in large differences in the direct cost of treating patients with duodenal ulcer disease who are positive for H pylori. In this analysis choosing H pylori eradication strategies on the basis of cost or efficacy alone did not identify the most cost effective strategy. If patients who fail eradication treatment are only treated for symptomatic relapses, once only treatment with omeprazole, clarithromycin, and metronidazole was the most cost effective approach to H pylori eradication despite being more expensive than omeprazole, amoxycillin, and metronidazole, and less effective than the two stage strategy of omeprazole, clarithromycin, and metronidazole. This is because the incremental costs of the most effective strategy of two stage omeprazole, clarithromycin, and metronidazole takes at least 15 years to be equalled (10 years if not discounted).