Background
Methods
Model overview
Intervention and comparator definition
Input parameters
Baseline parameters
Effect size
Māori (indigenous population) central estimate (95% CI)/[95% UI] | Non-Māori (rest of NZ population) central estimate (95% CI)/[95% UI] | |
---|---|---|
Effect size | ||
Meta-analysis rate ratio for incidence of gastric cancer in people with H. pylori infection who were treated compared to untreatedb
| Both: 0.66 (0.46–0.95) | |
Proportion gastric cancer that was non-cardia gastric cancer (2007-11) | ||
Men | 0.77 (0.69–0.85) | 0.45 (0.41–0.49) |
Women | 0.89 (0.82–0.96) | 0.63 (0.58–0.69) |
Non-cardia gastric cancer where H. pylori infection is detectablea
| 0.89 (0.85–1.00) | |
Sensitivity of the serology test (Se
sero
) | 0.89 [0.85–0.92] [28] | |
Expected coverage of serology test (using data from routine heart and diabetes checks in NZ adults [27])a
| 0.81 (0.69–0.93)b
| 0.84 (0.72–0.97)b
|
Eradication rate reported by studies in the meta-analysis [2] | 0.73 (0.71–0.75) | |
Eradication rate of OAC triple therapy in NZ, intention to treat [29]a
| 0.64 (0.53–0.75) | 0.86 (0.75–0.96) |
Eradication rate of OBTM quadruple therapy in NZ [16]a
| 0.7 [0.6–0.8] | |
Annual percentage decline in gastric cancer over time [5] | 0.02 [0.01–0.03] | |
Screening pathway | ||
H. pylori seroprevalence (proportion) by age-group (years) in 2011 [41] | ||
25–29 | 0.11 [0.07–0.14] | 0.08 [0.05–0.10] |
30–34 | 0.15 [0.11–0.20] | 0.10 [0.07–0.13] |
35–39 | 0.20 [0.14–0.25] | 0.13 [0.09–0.16] |
40–44 | 0.24 [0.17–0.31] | 0.15 [0.11–0.20] |
45–49 | 0.29 [0.20–0.37] | 0.18 [0.12–0.23] |
50–54 | 0.33 [0.23–0.43] | 0.20 [0.14–0.26] |
55–59 | 0.38 [0.26–0.49] | 0.23 [0.16–0.29] |
60–64 | 0.42 [0.29–0.55] | 0.25 [0.18–0.33] |
65–69 | 0.47 [0.33–0.60] | 0.28 [0.19–0.36] |
Risk of Clostridium difficile infection post-treatment (Brown et al., 2013) | 0.0008 [0.0004–0.0012] | |
Cost of hospitalization with moderate or severe C. difficile infection [34] | $3,856 [3085–4628] | |
Costs of screening program (NZ, 2011) (See Additional file 1: Table S2 for breakdown of costs and sources) | ||
Cost per person invited (fixed health promotion, program costs) | $39.87 [31.90–47.84] | |
Cost per person tested (test and result) | $54.66 [43.73–65.59] | |
Cost per person with a positive test (GP visit, treatment, retest, complications) | $176.70 [141.36–212.04] | |
Cost per person where eradication failed (GP visit, treatment, complications) | $129.85 [103.88–155.82] |
Costs
Screening program costs
Analyses
Uncertainty analysis
Scenario analyses
Results
Main analysis
Model output | Total population 25–69 yo | Māori 25-69 yo | Non-Māori 25–69 yo |
---|---|---|---|
Serology based screening | |||
Men and women | |||
Number cases of gastric cancer averted | 3658 (1252–4425) | 1007 (342–1828) | 2650 (905–4837) |
Percentage cases of gastric cancer averted | 16.5% (5.6%–29.4%) | 21.6% (7.4%–38.6%) | 15.2% (5.2%–27%) |
Number of gastric cancer deaths averted | 2434 (834–4425) | 714 (242–1293) | 1720 (588–3141) |
Percentage gastric cancer deaths averted | 16.6% (5.7%–29.5%) | 21.6% (7.3%–38.6%) | 15.2% (5.2%–27%) |
Total net incremental cost (NZ$ million) | $293 ($272–$314) | $41 ($35–$46) | $252 ($233–$272) |
Total intervention cost (NZ$ million) | $294 ($282–$307) | $41 ($38–$45) | $253 ($242-$264) |
Total cost offsets (NZ$ million) | -$1.5 (-$26.2–$22.9) | -$0.61 (-$7.35–$6.21) | -$0.89 ($-22.7–$21.7) |
Total QALYs gained | 14,200 (5100–26,300) | 4000 (1400–7400) | 10,200 (3653–18974) |
Incremental net cost per participant (NZ$) | $119 ($111–$128) | $137 ($117–$158) | $117 ($108–$126) |
Incremental QALYs gained per participant | 0.0058 (0.0020–0.0107) | 0.0137 (0.0047–0.0252) | 0.0047 (0.0016–0.0087) |
ICER (NZ$ per QALY gained) | $24,600 ($11,300–$57,400) | $12,000 ($5700–$27,600) | $29,600 ($13,400–$69,800) |
Men | |||
Incremental cost per participant (NZ$) | $123 ($113–$134) | $147 ($123–$173) | $120 ($110–$131) |
Incremental QALYs gained per participant | 0.0071 (0.0024–0.0131) | 0.0158 (0.0055–0.0293) | 0.0059 (0.0020–0.0110) |
ICER (NZ$ per QALY gained) | $20,800 ($9800–$47,900) | $11,000 ($5600–$24,300) | $24,300 ($11,300–$57,100) |
Women | |||
Incremental cost per participant (NZ$) | $116 ($108–$124) | $129 ($110–$148) | $114 ($105–$123) |
Incremental QALYs gained per participant | 0.0046 (0.0016–0.0085) | 0.0118 (0.0040–0.0217) | 0.0036 (0.0012–0.0067) |
ICER (NZ$ per QALY gained) | $30,200 ($13, 400–$71,400) | $13,200 ($5900–$31,300) | $38,000 ($16,800–$89,900) |
Fecal antigen based screening | |||
Men and women | |||
Total incremental cost (NZ$ million) | $369 ($350–$389) | $49 ($44–$55) | $320 ($301–$339) |
Total QALYs gained | 15,300 (5400–27,700) | 4200 (1500–7600) | 11,000 (3830–20,200) |
Incremental cost per participant (NZ$) | $150 ($142–$158) | $164 ($147–$182) | $148 ($139–$156) |
Incremental QALYs gained per participant | 0.0061 (0.0022–0.0111) | 0.0142 (0.0051–0.0259) | 0.0050 (0.0018–0.0092) |
ICER (NZ$ per QALY) | $29,000 ($13,600–$65,900) | $13,700 ($6700–$30,500) | $34,900 ($16,300–$79,100) |
Uncertainty analysis
Scenario analyses
Incremental costs (NZ$) | Incremental QALYs gained | Incremental cost-effectiveness ratio | |||||||
---|---|---|---|---|---|---|---|---|---|
Total | Māori | Non-Māori | Total | Māori | Non-Māori | Total | Māori | Non-Māori | |
Main modela
| $119 | $138 | $117 | 0.006 | 0.014 | 0.005 | $20,600 | $10,100 | $24,700 |
Equity analysis—equal life expectancy and background morbidity for Māori and non-Māori | $121 | $155 | $117 | 0.006 | 0.019 | 0.005 | $18,800 | $8,200 | $24,700 |
Equal coverage—coverage in Māori was set to the same as non-Māori (84%) | $120 | $143 | $117 | 0.006 | 0.014 | 0.005 | $20,400 | $10,000 | $24,700 |
Low coverage—coverage in Māori of 45% and non-Māori of 58% akin to a NZ colorectal screening pilot | $93 | $95 | $93 | 0.004 | 0.008 | 0.003 | $24,500 | $12,400 | $28,400 |
Equal eradication—triple therapy was increased to be 95% effective (e.g. levofloxacin) | $118 | $132 | $116 | 0.006 | 0.015 | 0.005 | $19,600 | $8,900 | $24,200 |
No retest to ensure effective eradication | $101 | $107 | $100 | 0.005 | 0.010 | 0.004 | $20,600 | $10,900 | $23,600 |
Follow-up for 15 years (rather than over a lifetime) | $118 | $132 | $116 | 0.003 | 0.008 | 0.003 | $35,600 | $16,000 | $44,000 |
The effect size in the youngest age groups is greater (<40yo, RR of 0.50) | $119 | $139 | $117 | 0.006 | 0.016 | 0.005 | $18,400 | $8,700 | $22,500 |
The complication rate for CDI was increased from 80 to 800 per 100,000 | $124 | $146 | $121 | 0.006 | 0.014 | 0.005 | $21,400 | $10,700 | $25,600 |
6% discounting QALYs and costs | $112 | $118 | $111 | 0.003 | 0.007 | 0.002 | $39,200 | $17,300 | $48,200 |
0% discounting QALYs and costs | $151 | $225 | $141 | 0.015 | 0.034 | 0.012 | $10,300 | $6,600 | $11,700 |
No unrelated health system costs | $82 | $52 | $86 | 0.006 | 0.014 | 0.005 | $14,200 | $3,800 | $18,300 |
No pYLDs (background morbidity) | $119 | $138 | $117 | 0.008 | 0.021 | 0.007 | $14,300 | $6,700 | $17,500 |