21 Jan

Test and treat strategies for Helicobacter: RESULTS

RESULTS

Base case scenario: The number of endoscopies per 1000 pa­tients was lowest with the C-UBT strategy, higher with serology and highest with empirical ranitidine therapy (Table 3). The number of H pylori eradica­tion regimens prescribed per 1000 patients was lowest with empirical ranitidine (200.1), highest with serology and intermediate with the 13C-UBT.

In the base case scenario, the direct medical cost per pa­tient over 12 months was $598 in the ranitidine strategy, $635 in the C-UBT strategy and $603 in the serology strategy (Table 3). The number of H pylori-positive peptic ulcers cured was 53/1000 patients with the ranitidine strategy, 128/1000 patients with the 13C-UBT and 92/1000 patients with serology. No strategy demonstrated dominance over any other because none was both more effective and less costly (Figure 2). The ratio of total cost to total number of ul­cers cured was highest with ranitidine ($11,300/cure), inter­mediate with the serology strategy ($6,543/cure) and lowest with the 13C-UBT test and treat strategy ($4,945/cure).

TABLE 3 Expected one-year outcomes, costs and incremental cost effectiveness ratios (ICER). Reported results are rounded to the nearest whole value, while calculations have been performed on unrounded values

Endoscopies

Cost per

Cost

Ulcer cures

per
1000

H
pylori

treatments

patient

increment,

per
1000

Increment in
ulcer

ICER

Strategy

patients

per
1000
patients

(CDN$)


CDN$

(6C)

patients

cures
(d
E)

((5CA5EX1000)

Ranitidine

700

200

598

53

H pylori serology

649

449

603

5

92

39

$118/cure

13C-UBT

629

433

635

32

128

36

$885/cure

The incremental change in cost and ulcer cures was deter­mined by advancing from the least costly and least effective strategy (ranitidine) to the most costly and most effective option (13C-UBT). The ICER of serology compared with ranitidine was $118 per additional ulcer cure, while that of 13 the C-UBT relative to serology was $885/cure. One-way sensitivity analysis: Each path probability and cost estimate were varied over their plausible range to deter­mine their impact on the ICERs of 13C-UBT versus serol­ogy and of serology versus ranitidine. In several instances, an ICER fell below zero, implying a dominant relationship be­tween the two alternatives. In such cases, a ‘dominance threshold’ value for that model parameter was identified as the point where the ICER numerator (cost increment) or de­nominator (effect increment) approached zero.

TABLE 4 One-way sensitivity analysis examining the incremental cost effectiveness ratio (ICER) of the serology strategy versus empirical ranitidine

Model parameter

Range

ICER range ($/cure)

Serology
dominant (threshold)

ICER >$1000/cure
(threshold)

Serology sensitivity

0.70-0.95

47-262

N/A

N/A

Serology specificity

0.70-0.95

0-187

Over 0.94

N/A

Helicobacter pylori prevalence in dyspepsia

0.10-0.50

0-1400

Over 0.35

Below0.14

PUD prevalence if H pylori-positive

0.20-0.50

0-752

Over 0.39

N/A

PUD recurrence if H pylori-positive

0.50-1.00

0-282

Over 0.88

N/A

PUD recurrence if H pylori-negative

0.00-0.20

65-336

N/A

N/A

H pylori eradication effectiveness

0.60-1.00

3-492

N/A

N/A

Relapse rate of NUD

0.00-1.00

45-253

N/A

N/A

Proportion of PUD patients with symptoms

0.00-1.00

0-550

Over 0.83

N/A

Cost of endoscopy

$250-$1250

0-442

Over $610

N/A

Cost of serology

$5-$50

0-883

Below $16

N/A

The ICER of serology versus ranitidine ranged from $0/cure to $1400/cure in sensitivity analysis (Table 4). In no circumstance did ranitidine become dominant over serology. However, serology dominated ranitidine when any of the following conditions were satisfied: prevalence of H pylori greater than 35%; prevalence of PUD greater than 39% if H pylori-positive; specificity of serology greater than 94%; proportion of ulcers with symptoms greater than 83%; an­nual relapse rate of H pylori–positive patients with prior PUD greater than 88%; cost of serology less than $16; or cost of endoscopy greater than $610.
Don’t blow your budget on pharmacy items now

Figure 2) Base case scenario estimates

Figure 2) Base case scenario estimates of costs and outcomes (ulcer cures per 1000 patients) for three alternative strategies. Dashed lines represent the incremental cost effectiveness ratios of successive strategies. *($603-$598)/(92-53) x 1000 (values rounded); +($635-$603)/ (128-92) x 1000 (values rounded). HP Helicobacter pylori

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