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

Table 4 Sensitivity analysis of models 1 and 2 assessing cost
effectiveness of eight antibiotic strategies for eradication
of Helicobacter pylori

                                        No of years for future
                                        treatment costs to exceed
                                        incremental direct
                                        costs of strategy 4
                                        (discounted)

                                                Model 1

                             Base       Once      Once
                             case       only      only      OAM 
Variables and range          estimate   OAM       OCM       OCM

Base case estimate                       7.9      15.7       6.9
OCM efficacy (%)              91
 89                                      8.6      11.6      11.8
 92                                      7.6      19.3       5.8
OCM efficacy after
eradication failure (%):      63
 55                                      8.6      20.0       5.5
 71                                      7.4      13.1       9.5
OAM efficacy (%):             85
 82                                      6.0      15.7       2.8
 87                                     10.2      15.7       7.1
OCM cost per patient
([pounds sterling]):
 20                                      5.7      15.1       0.0
 40                                     11.0      16.5      27.5
OAM cost per patient
([pounds sterling]):
 10                                     10.6      15.7      27.6
 30                                      5.8      15.7       0.0
UBT cost: per patient
([pounds sterling]):
 20                                      5.6       9.0       7.3
 40                                     10.4      24.9       7.3
Efficacy and costs to OCM:
 Most favourable(*)                      3.3       >50       0.0
 Least
  favourable([dagger])                  29.9      15.5       >50
Treatment cost of
recurrent ulcers per year
([pounds sterling]):
 13.88                                   >50       >50       >50
 70.90                                   5.9      10.9       5.2
Maintenance treatment
cost per year
([pounds sterling]):
 83.72
 259.35

                              No of years for future treatment
                              costs to exceed incremental direct
                              costs of strategy 4 (discounted)

                                          Model 2

                                Once        Once
                                only        only        OAM 
Variables and range             OAM         OCM         OCM

Base case estimate              0.8         0.6         1.7
OCM efficacy (%)
 89                             0.8         0.8         2.8
 92                             0.6         0.3         1.5
OCM efficacy after
eradication failure (%):
 55                             0.8         0.7         1.4
 71                             0.7         0.5         2.2
OAM efficacy (%):
 82                             0.6         0.6         0.2
 87                             0.9         0.6         0.5
OCM cost per patient
([pounds sterling]):
 20                             0.2         0.5         0.0
 40                             1.4         0.7         4.8
OAM cost per patient
([pounds sterling]):
 10                             1.3         0.6         4.8
 30                             0.3         0.6         0.0
UBT cost: per patient
([pounds sterling]):
 20                             0.7         0.5         1.9
 40                             0.8         0.7         1.6
Efficacy and costs to OCM:
 Most favourable(*)             0.0         0.5         0.0
 Least
  favourable([dagger])          3.1         0.9         >50
Treatment cost of
recurrent ulcers per year
([pounds sterling]):
 13.88
 70.90
Maintenance treatment
cost per year
([pounds sterling]):
 83.72                          1.6         1.2         3.5
 259.35                         0.5         0.4         1.1

OAM=omeprazole, amoxycillin, and metronidazole; OCM=omeprazole, clarithromycin, and metronidazole.

(*) OCM efficacy 92%, OCM efficacy after eradication failure 71%, OAM efficacy 82%, OCM 20 [pounds sterling] per patient, OAM 30 [pounds sterling] per patient.

([dagger]) OCM efficacy 89%, OCM efficacy after eradication failure 55%, OAM efficacy 85%, OCM 40 [pounds sterling] per patient, OAM 10 [pounds sterling] per patient.

In model 1 assuming an efficacy of only 55% for omeprazole, clarithromycin, and metronidazole when given as second line treatment had no effect on the comparative cost effectiveness of the alternative strategies. In only two situations (table 4) were omeprazole, amoxycillin, and metronidazole based strategies more cost effective than omeprazole, clarithromycin, and metronidazole alone. Firstly, increasing the cost of the omeprazole, clarithromycin, and metronidazole regimen to 40.00 [pounds sterling] made the omeprazole, amoxycillin, and metronidazole followed by omeprazole, clarithromycin, and metronidazole strategy more cost effective than omeprazole, clarithromycin, and metronidazole alone. The two stage strategy with first line treatment with omeprazole, amoxycillin, and metronidazole had a cost advantage compared with the two stage strategy of omeprazole, clarithromycin, and metronidazole for over 27 years of treatment for relapses (14 years not discounted). Secondly, assuming the least favourable efficacy (89%) and costs (40 [pounds sterling]) for omeprazole, clarithromycin, and metronidazole resulted in both omeprazole, amoxycillin, and metronidazole based strategies being more cost effective. The strategy of once only omeprazole, amoxycillin, and metronidazole achieved a cost advantage for 30 years of treatment of relapses (14 years not discounted) and the two stage strategy of omeprazole, amoxycillin, and metronidazole for over 50 years.

Relative cost effectiveness was not sensitive to any of the other ranges used, to the other efficacy variables, or to the cost of the [13]C-urea breath test. In each case a strategy of once only omeprazole, clarithromycin, and metronidazole had the best outcome. The number of years, however, for the cost of treatment for relapses for the additional patients positive for H pylori to exceed the incremental costs of the two stage strategy of omeprazole, clarithromycin, and metronidazole was sensitive to the annual cost of treatment for relapses. If an annual cost of treatment for recurrent ulcers of 70.90 [pounds sterling] per patient is incurred for a treatment based on omeprazole (expected relapse of 5.2 weeks per annum of full dose treatment) the incremental direct costs of a two stage strategy of omeprazole, clarithromycin, and metronidazole are equalled in just over 10 years (8.3 years not discounted). For the other two strategies only about 6 years are required.