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APPENDIX 7
Helicobacter pylori

DISEASE BURDEN

Epidemiology

H. pylori is also believed to play a role in peptic ulcer disease. This speculation came about after the organism was found to be present more frequently in idiopathic peptic ulcer disease than in age-matched controls. Furthermore, H. pylori has been associated with duodenal ulcers. Chronic superficial gastritis may progress to chronic gastric atrophy with the possible risk of gastric adenocarcinoma. Therefore, H. pylori can be considered a risk factor for gastric cancer.

For the purposes of the calculations in this report, the committee estimated that there are approximately 1,240,000 new infections of Helicobacter pylori (H. pylori) each year in the United States. The incidence rate is highest in people between the ages of 1 and 24 years of age; it was assumed that there are no new infections after 44 years of age. It was assumed that there are approximately 14,500 deaths annually due to H. pylori infection. Most of these deaths occur in people 65 years of age or older. See Table A7–1.

See Appendix 28 for more information.



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Vaccines for the 21st Century: A Tool for Decisionmaking APPENDIX 7 Helicobacter pylori DISEASE BURDEN Epidemiology H. pylori is also believed to play a role in peptic ulcer disease. This speculation came about after the organism was found to be present more frequently in idiopathic peptic ulcer disease than in age-matched controls. Furthermore, H. pylori has been associated with duodenal ulcers. Chronic superficial gastritis may progress to chronic gastric atrophy with the possible risk of gastric adenocarcinoma. Therefore, H. pylori can be considered a risk factor for gastric cancer. For the purposes of the calculations in this report, the committee estimated that there are approximately 1,240,000 new infections of Helicobacter pylori (H. pylori) each year in the United States. The incidence rate is highest in people between the ages of 1 and 24 years of age; it was assumed that there are no new infections after 44 years of age. It was assumed that there are approximately 14,500 deaths annually due to H. pylori infection. Most of these deaths occur in people 65 years of age or older. See Table A7–1. See Appendix 28 for more information.

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Vaccines for the 21st Century: A Tool for Decisionmaking Table A7–1 Incidence and Mortality Rates of H. pylori Infection Age Groups Population % Distribution of Cases Cases INCIDENCE   <1 3,963,000 .0160 19,815 1–4 16,219,000 .1309 162,190 5–14 38,056,000 .3072 380,560 15–24 36,263,000 .2927 362,630 25–34 41,670,000 .1682 208,350 35–44 42,149,000 .0851 105,373 45–54 30,224,000 .0000 0 55–64 21,241,000 .0000 0 65–74 18,964,000 .0000 0 75–84 11,088,000 .0000 0 85+ 3,598,000 .0000 0 Total 263,435,000 1,000 1,238,918 Age Groups Population % Distribution of Deaths Cases MORTALITY   <1 3,963,000 0.0004 6 1–4 16,219,000 0.0002 3 5–14 38,056,000 0.0001 2 15–24 36,263,000 0.0016 23 25–34 41,670,000 0.0085 431 35–44 42,149,000 0.0296 943 45–54 30,224,000 0.0647 1,781 55–64 21,241,000 0.1223 3,572 65–74 18,964,000 0.2453 4,510 75–84 11,088,000 0.3096 3,169 85+ 3,598,000 0.2176   Total 263,435,000 1.0000 14,500 Disease Scenarios For the purposes of the calculation in this report, the committee assumed that there are acute and chronic manifestations of H. pylori infection (see Table A7–2). Some of the chronic manifestations last for decades; others manifest for much shorter periods of time. It was assumed that 30% of people infected with H. pylori experience a week of acute gastritis. Half of those people go on to experience recurrent attacks of gastritis (approximately 2 days per month) for the lifetime of the person with no other complications. The health utility index (HUI) associated with gastritis was estimated to be .74. It was assumed that approximately 10% of infections are associated with approximately 30 years of recurrent gastritis, followed by peptic ulcer disease.

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Vaccines for the 21st Century: A Tool for Decisionmaking Table A7–2 Disease Scenarios for H. pylori Infection   No. of Cases % of Cases Committee HUI Values Duration (years) GASTRITIS:   Gastritis 371,675 30.0%   acute gastritis at initial infection   0.74 0.0192 (1 week) Gastritis—recurrent 185,838 15.0%   chronic mild symptoms—no transition to PUD   0.74 1.5848 (2 days/month for life) Gastritis to Peptic Ulcer Disease 123,892 10.0%   chronic mild symptoms until PUD diagnosis made   0.74 2 days/month; continues for average of 30 years PEPTIC ULCER DISEASE   Peptic Ulcer Disease 123,892 10.0%   acute PUD   0.61 0.0192 (1 week) Peptic Ulcer Disease (untreated or recurrence) 61,946 5.0% 0.74 1.0832 (2 days/month for life) Peptic Ulcer Disease (w/complications) 2,478 0.2% 0.4 0.0384 (2 weeks) GASTRIC CANCERS   Gastric Adenocarcinoma 12,389 1.0% 0.82 1.0000 (average life expectancy from diagnosis) Lymphomas/MALTomas 6,195 0.5% 0.82 7.5000 (average life expectancy from diagnosis) It was assumed that there is a 30-year latency between time of infection and acute peptic ulcer disease; half of the people with acute peptic ulcer disease experience chronic peptic ulcer disease for the duration of their lives. It was further assumed that a small proportion (1.5%) of infected people develop cancer secondary to the H. pylori infection and that the cancers are diagnosed around age 70 and that these people die within a year. HUI states associated with these latent conditions range from .40 for acute complications of peptic ulcer disease to .74 for recurrences of chronic, mild peptic ulcer disease, to .82 for the average state during the year of life from diagnosis of cancers to death. COST INCURRED BY DISEASE Table A7–3 summarizes the health care costs incurred by H. pylori infections. For the purposes of the calculations in this report, it was assumed that

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Vaccines for the 21st Century: A Tool for Decisionmaking Table A7–3 Health Care Costs Associated with H. pylori Infections   % with Care Cost per Unit Units per Case Form of Treatment GASTRITIS   acute gastritis at initial infection 100% $10 1.0 medication a   80% $50 1.0 physician a 25% $100 1.0 physician b 50% $50 1.0 diagnostic a 50% $100 1.0 diagnostic b 10% $1,000 1.0 outpatient surgery 5% $500 2.0 surgical staff 25% $150 1.0 medication c Gastritis—recurrent   chronic mild symptoms—no transition to PUD 100% $10 1.0 medication a 2 days per month; continues for remaining lifetime 10% $50 1.00 physician a   5% $100 1.00 physician b Gastritis to PUD   chronic mild symptoms until PUD diagnosis made 100% $10 6.0 medication a 2 days per month; continues for 30 years 10% $50 1.00 physician a PEPTIC ULCER DISEASE:   average 30-year lag from initial infection   Peptic Ulcer Disease   acute PUD 100% $10 1.0 medication a   100% $50 1.0 physician a 100% $100 2.0 physician b 50% $500 1.0 diagnostic c 25% $1,000 1.0 outpatient surgery 25% $500 2.0 surgical staff 25% $500 1.0 diagnostic c 75% $150 1.0 medication c Peptic Ulcer Disease (untreated)   chronic mild symptoms 100% $10 1.0 medication a 2 days per month; continues for remaining lifetime 100% $50 1.00 physician a   25% $100 1.00 physician b 50% $50 1.00 diagnostic a 50% $150 1.00 medication c Peptic Ulcer Disease (w/complications)     100% $50 1.0 physician a 100% $100 2.0 physician b 100% $500 1.0 diagnostic c 75% $3,000 1.0 hospitalization w/o surgery

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Vaccines for the 21st Century: A Tool for Decisionmaking   % with Care Cost per Unit Units per Case Form of Treatment Peptic Ulcer Disease (w/complications) 25% $6,000 1.0 hospitalization w/surgery   100% $150 1.0 medication c GASTRIC CANCERS:   Gastric adenocarcinoma, lymphomas, MALTomas 100% $50 6.0 physician a   100% $75 6.0 physician b 100% $500 1.0 diagnostic c 100% $4,000 1.0 hospitalization 100% $500 2.0 surgical staff 100% $500 1.0 diagnostic c 100% of people experiencing gastritis incur costs for inexpensive over-the-counter medication, but that only 10% incur costs for a limited visit to a physician. It was assumed that 5% of patients with gastritis visit a specialist. For recurrent disease, it was assumed that costs incurred include 1 visit to a physician per year and 6 purchases of over-the-counter medication per year for lifetime or until a diagnosis of peptic ulcer disease is made. It was assumed that all patients with acute peptic ulcer disease (PUD) incur costs associated with over-the-counter medications, a limited visit to a physician, and two visits to a specialist. It was assumed that half these patients receive a relatively expensive diagnostic procedure. It was assumed that 25% of patients receive ambulatory surgery for these symptoms, and that 75% of acute PUD patients receive expensive prescription medications. Similar patterns and costs of care were assumed for the patients with chronic, mild peptic ulcer disease (each year for the remainder of life). The patients who experience serious complications of PUD incur costs for hospitalization and follow-up. It was assumed that all patients with gastric adenocarcinomas and lymphomas receive extensive care during the year of life from diagnosis to death. Costs included in the analysis are multiple visits to a general physician and a specialist, expensive diagnostics, and one hospitalization. The annualized present value of the cost of care averted by a vaccine strategy (with the program assumptions described below) is approximately $70,000,000. VACCINE DEVELOPMENT The committee assumed that will take 7 years until licensure and that $240 million needs to be invested. Table 4–1 summarized vaccine development estimates for all candidates considered in this report.

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Vaccines for the 21st Century: A Tool for Decisionmaking VACCINE PROGRAM CONSIDERATIONS Target Population For the purposes of the calculations in this report, it is assumed that the target population for this vaccine the annual birth cohort of the United States. It was assumed that 30% of the target population would utilize the vaccine. Vaccine Schedule, Efficacy, and Costs For the purposes of the calculations in this report, it was estimated that this vaccine would cost $50 per dose and that administration costs would be $10 per dose. Default assumptions of a 3-dose series and 75% efficacy were accepted. Table 4–1 summarizes vaccine program assumptions for all vaccines considered in this report. RESULTS If a vaccine program for H. pylori were implemented today and the vaccine was 100% efficacious and utilized by 100% of the target population, the annualized present value of the QALYs gained would be 90,000. Using committee assumptions of less-than-ideal efficacy and utilization and including time and monetary costs until a vaccine program is implemented, the annualized present value of the QALYs gained would be 14,000. The majority of these lost QALYs are associated with gastritis, because of the large number of cases. If a vaccine program for H. pylori were implemented today and the vaccine was 100% efficacious and utilized by 100% of the target population, the annualized present value of the health care costs saved would be $430 million. Using committee assumptions of less-than-ideal efficacy and utilization and including time and monetary costs until a vaccine program is implemented, the annualized present value of the health care costs saved would be $67.3 million. If a vaccine program for H. pylori were implemented today and the vaccine was 100% efficacious and utilized by 100% of the target population, the annualized present value of the program cost would be $720 million. Using committee assumptions of less-than-ideal efficacy and utilization and including time and monetary costs until a vaccine program is implemented, the annualized present value of the program cost would be $150 million. Using committee assumptions of time and costs until licensure, the fixed cost of vaccine development has been amortized and is $7.2 million for a H. pylori vaccine. If a vaccine program were implemented today and the vaccine were 100%

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Vaccines for the 21st Century: A Tool for Decisionmaking efficacious and utilized by 100% of the target population, the annualized present value of the cost per QALY gained is $3,300, Using committee assumptions of less-than-ideal utilization and including time and monetary costs until a vaccine program is implemented, the annualized present value of the cost per QALY gained is $6,500. See Chapters 4 and 5 for details on the methods and assumptions used by the committee for the results reported. READING LIST Blaser MJ. Helicobacter pylori and Related Organisms. In: Principles and Practice of Infectious Diseases. GL Mandell, JE Bennett, Dolin R eds. New York, NY: Churchill Livingstone, 1995, pp. 1956–1964. CDC. Compressed Mortality Database. WONDER (wonder.cdc.gov). 1997. ICD-9, Number 531–533. Dubois A. Spiral Bacteria in the Human Stomach: The Gastric Helicobacters. Emerging Infectious Diseases 1995; (1)3:79–83. Fendrick AM, Chernew ME, Hirth RA, et al. Alternative Management Strategies for Patients with Suspected Peptic Ulcer Disease. Annals of Internal Medicine 1995; 123:260–268. Hansson LE, Nyren O, Hsing HW, et al. The Risk of Stomach Cancer in Patients with Gastric or Duodenal Ulcer Disease. The New England Journal of Medicine 1996; 335:242–249. Marshall BJ. Helicobacter pylori—The Etiologic Agent for Peptic Ulcer. JAMA 1995; 274:1064–1066. Miller BA, Kolonel LN, Bernstein L, et al. (eds). Racial/Ethnic Patterns of Cancer in the United States 1988–1992, National Cancer Institute. NIH Pub. No. 96–4104. Bethesda, MD, 1996. NIH. Helicobacter pylori in Peptic Ulcer Disease. JAMA 1994; 272:65–69. Ofman JJ, Etchason J, Fullerton S, et al. Management Strategies for Helicobacter pylori-seropositive Patients with Dyspepsia: Clinical and Economic Consequences. Annals of Internal Medicine 1997; 126:280–291. Parsonnet J. Helicobacter pylori in the Stomach—a Paradox Unmasked. The New England Journal of Medicine 1996; 335:278–280. Ruiz-Palacios G, Pickering LK. Campylobacter and Helicobacter Infections. In: Textbook of Pediatric Infectious Diseases. RD Feigin and JD Cherry eds. Philadelphia, PA: WB Saunder Company, 1992, pp. 1062–1067. Singh GK, Kochanek KD, MacDorman MF. Advance Report of Final Mortality Statistics, 1994. Monthly Vital Statistics Report 1996; 45. Sonnenberg A, Everhart JE. The Prevalence of Self-Reported Peptic Ulcer in the United States. American Journal of Public Health 1996; 86:200–5. Staat MA, McQuillan GM. A Population-Based Serologic Survey of Helicobacter pylori Infection in Children and Adolescents in the United States. The Journal of Infectious Diseases 1996; 174:1120–1123.

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