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

Introduction

The value of eradicating Helicobacter pylori in duodenal ulcer disease is well established,[1] and eradication rates in excess of 80% are regularly reported. Some regimens, however, have slightly higher eradication rates than others. The regimen of omeprazole, clarithromycin, and metronidazole has been reported to achieve a higher eradication rate than the regimen of omeprazole, amoxycillin, and metronidazole (91% v 85%).[1] We examined how these small differences in efficacy affect the comparative cost effectiveness of strategies for eradicating H pylori, and how the choice of management of patients in whom eradication treatment failed affected the comparative cost effectiveness of each eradication strategy.

There are currently two methods for treating patients with duodenal ulcer disease who remain positive for H pylori after eradication treatment: (a) identifying the patients in whom eradication treatment has been unsuccessful and giving those who are positive for H pylori maintenance treatment and (b) not testing the patients and treating only those with recurrent ulcers that produce symptoms.

We used decision analysis to investigate whether the greater effectiveness of eradication strategies based on clarithromycin for patients with duodenal ulcer disease associated with H pylori justifies the additional costs.

Methods

We used two decision analysis models to compare the cost effectiveness of two H pylori eradication regimens with or without a subsequent confirmatory [13]C-urea breath test, and a second course for patients in whom eradication was unsuccessful.

Decision analysis was based on DATA 2.6 software (Treeage Software, Williamstown, MA) and the Excel 5.0 spreadsheet (Microsoft, Seattle, WA).

Efficacy data--Table 1 shows the variables assessed in the models and the source of the estimates. Estimates for the eradication of H pylori with each regimen and the 95% confidence intervals were obtained by calculating the mean eradication rates of H pylori from published non-randomised trials up to November 1995.[1] For the omeprazole, clarithromycin, and metronidazole regimen there were 15 such trials, totalling 1125 patients, with an overall eradication rate of 91%, and for the omeprazole, amoxycillin, and metronidazole regimen there were four such trials, totalling 673 patients, with an overall eradication rate of 85%.[1] Similar differences have been reported.[1, 2] Estimates for the eradication of H pylori with the omeprazole, clarithromycin, and metronidazole strategy after initial failure with either regimen were obtained by calculating the mean eradiction rates of H pylori using this regimen in patients who had previously failed eradication treatment from all trials up to October 1996.

Table 1 Source of estimates for variables used in two models
assessing cost effectiveness of eight antibiotic regimens for
eradication of Helicobacter pylori

                                        Base
                                        case
Variable                              estimate        Range

Efficacy (%):

Omeprezole, clarithromycin,
and metronidazole                       91            89-92

Repeat omeprazole,
clarithromycin, and
metronidazole after failure
to eradicate H pylori                   63            55-71

Omeprazole, amoxycillin, and
metronidazole                           85            82-87

Cost ([pounds sterling]):

Omeprazole, clarithromycin,
and metronidazole treatment            29.20          20-40

Omeprazole, amoxycillin, and
metronidazole treatment                20.20          10-30

[13]C-urea breath test                 30.80          20-40

Relapse treatment with
ranitidine 150 mg twice
daily (two prescriptions
per year)                              55.60       13.88-70.90

Maintenance treatment of
duodenal ulcer disease with
ranitidine 150 mg daily
(per year)                            167.28       83.72-259.35

Relapse treatment with
omeprazole 20 mg daily (two
prescriptions per year)                70.90

Maintenance treatment of
duodenal ulcer disease with
omeprazole 10 mg daily
(per year)                            259.35

Relapse treatment with
cimetidine 400 mg twice
daily (two prescriptions
per year)                              13.88

Maintenance treatment with
cimetidine 400 mg daily
(per year)                             83.72

Duration of relapse
treatment (weeks/year)                  5.2

Variable                           Source

Efficacy (%):

Omeprezole, clarithromycin,        Logan, 1996
and metronidazole

Repeat omeprazole,                 Moayyedi et al, 1995
clarithromycin, and                Lamouliatte et al, 1996
metronidazole after failure
to eradicate H pylori

Omeprazole, amoxycillin, and       Logan, 1996
metronidazole

Cost ([pounds sterling]):

Omeprazole, clarithromycin,        British National Formulary,
and metronidazole treatment        1996

Omeprazole, amoxycillin, and       British National Formulary,
metronidazole treatment            1996

[13]C-urea breath test             Bureau of Stable Isotope
                                   Analysts, 1996

Relapse treatment with             British National Formulary,
ranitidine 150 mg twice            1996
daily (two prescriptions
per year)

Maintenance treatment of           British National Formulary,
duodenal ulcer disease with        1996
ranitidine 150 mg daily
(per year)

Relapse treatment with             British National Formulary,
omeprazole 20 mg daily (two        1996
prescriptions per year)

Maintenance treatment of           British National Formulary,
duodenal ulcer disease with        1996
omeprazole 10 mg daily
(per year)

Relapse treatment with             British National Formulary,
cimetidine 400 mg twice            1996
daily (two prescriptions
per year)

Maintenance treatment with         British National Formulary,
cimetidine 400 mg daily            1996
(per year)

Duration of relapse                Sonnenberg, 1989
treatment (weeks/year)