Influenza vaccine cost-effectiveness in elderly with chronic illness

1. 1 Influenza vaccine cost-effectiveness in elderly with chronic illness Potjaman Siriarayapon*, Jongkol Lertiendumrong**, Benjawan Raluek*, Vichan Pawan* *FETP, ** IHPP

2. 2 Backgrounds In 2008, National Health Security Office (NHSO) and EPI Thailand plan to implement influenza vaccine in elderly with chronic illness : COPD, asthma, heart disease, CRF, stroke, DM, and cancer patients currently on chemotherapy Due to insufficient vaccine supply, this year was started with about 120,000 doses of the influenza vaccine Plan to implement during 1-30 June 2008, nationwide in patients with history of hospitalization with these 7 chronic illness during 2007-2008

3. 3 Backgrounds There is a request from NHSO to have a study to evaluate the cost-effectiveness of this policy There were 3-4 components in this study Cost- effectiveness study KAP Side effect of influenza vaccine

4. 4 Effect of influenza vaccine in different groups (1) General elderly: reduce influenza incidence, hospitalized from influenza, pneumonia and reduce mortality from all causes COPD*: reduce influenza incidence, hospitalized from influenza & pneumonia, exacerbation of COPD and reduce mortality from all causes (strong effect compare to other diseases)

5. 5 Effect of influenza vaccine in different group (2) Coronary artery disease: reduce re-infarction, re-hospitalization and reduce cardiovascular death but some study reported negative finding of reduce risk for recurrent MI or cardiovascular death Controversy reported in DM, CRF, stroke, asthma, cancer who is on chemotherapy

6. General objective To assess influenza vaccine effectiveness for preventing confirmed influenza infection in elderly people with 7 chronic diseases listed in the plan of influenza vaccination

7. 7 Specific objectives Study influenza vaccine effectiveness in elderly people that have 6 chronic diseases to reduce ILI and pneumonia Hospitalization from influenza and other medical conditions Death from all cause Study influenza vaccine effectiveness in elderly people with acute MI to reduce Re-infarction Re-hospitalization from coronary diseases and all heart condition Death from CAD

8. 8 Methodology Study design: prospective cohort study to compare between vaccinated and unvaccinated population Study sites: Pitsanulok and Udonthani provincial hospitals Hospitals large enough to have necessary tool to assess disease status at enrolment i.e. spirometer Not have large medical school Have doctor that willing to participate the study

9. 9 Study population* People age >65 years who stayed in Muang district and was diagnosed by doctor as COPD Asthma DM CRF Stroke Cancer with chemotherapy Elderly >65 years who was diagnosed by doctor with acute MI

10. 10 Exclusion criteria Refuse to participate Not allow to collect blood at enrollment Can not come to hospital for physical and laboratory examination at enrollment Can not communicate in Thai (self and close relative) Monk or nun

11. 11 Sampling of study population Sampling frame: Vaccinated group: list of patient who already received vaccine in June 2008 Unvaccinated group: patients with target diseases who had history of hospitalization in the past 3-5 years* but did not get influenza vaccine in 2008

12. 12 Sample size Divided to 2 subgroups Acute MI Other 6 diseases

13. Sample size of 6 diseases The other 6 diseases Confidence interval 95% power 80% Incidence of influenza 7.2%* Relative risk 0.55** Unvaccinated : vaccinated = 1.5:1 Sample size two arms = 1160 Adjusted for 20% loss F/U = 1400

14. 14 Sample size of acute MI Specified value Confidence interval 95% power 80% Incidence of death, re-infarction, re-hospitalization about 23%* (19%)** Relative risk 0.42* (50%)** Unvaccinated : vaccinated = 1.5:1 Sample size two arms= 493 Adjusted for 20% loss F/U= 600

15. 15 Total sample size and each subgroup Total = 2000 Ac MI = 600 Other 6 chronic diseases = 1400 COPD DM Asthma CRF Stroke Cancer with chemotherapy

16. 16 Case definition 7 target diseases: doctor diagnosis ILI: fever with cough or sore throat in the absence of a known cause other than influenza Confirmed influenza: PCR from throat swab or 4 fold rising of HI titer

17. 17 Data collection Variables Tool Methods

18. 18 Variables (1) Exposure: Influenza vaccine, from document and interview Outcome data Influenza incidence Hospitalization from all medical conditions Death from all cause

19. 19 Variables (2) Potential confounders: Influenza Number of household member Number of children in household Previous influenza vaccination (self & household member) Immunocompromised host (HIV or steroid)

20. 20 Potential confounders: all 7 diseases Demographic data: age, gender, address, socioeconomic status (wealth index) Severity of each disease* Co-morbidity: History of the other chronic diseases such as hypertension, rheumatologic disease (use CCI**) History of smoking (including in family), alcoholic, drug addicted Variables (3)

21. 21 Severity of target diseases COPD: FEV1 percent predicted Acute MI: New York heart classification Asthma: GINA score Stroke: functional status (ADL) DM: with or without complication CRF: creatinine, creatinine clearance Cancer: type and stage of the disease

22. 22 Variables (4) Potential confounders: Acute MI Hyperlipidemia Physical inactivity Family history of CAD Cardiac medication & other important medication (antihypertention, lipid lowering, ASA, multivitamin (B6, folic,) , NSAID

23. 23 Variables (5) Potential confounders: COPD Severity of COPD (FEV1) Steroid used (systemic, inhale) Long acting-inhale �2 agonist

24. 24 Data collection tool Data collection form Structured questionnaire to interview participants at enrollment and during F/U Data abstraction form to review medical records of the participants Basic laboratory at enrollment COPD: FEV1 if not measure in previous 1 year

25. 25 Laboratory confirm of influenza At enrollment: collect serum to see the baseline immunity level before infection (should be at least 1 months after vaccination) During follow up Indicator: All cases with ILI or suspected influenza complications (exacerbation of the chronic diseases, and pneumonia) Test If can collect specimen within 7 days after onset of ILI: throat swab for RT-PCR If longer than 7 days: pair serum for HI

26. 26 Data collection methods Enrollment Place: at health center Period: 1-2 months F/U of participants Telephone every 2 weeks If loss F/U > 4 weeks, research assistant will visit their house, will exclude if can not contact for > 6 weeks

27. 27 Data entry & analysis Internet fax to data management team Validate at central level by data management team (Trop. Med.) X2 and t-test to compare groups of discrete and continuous variables Cox proportional hazard models will use for calculation of hazard ratios and 95%CI

28. 28 Budget estimation ~ 10 million baht

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33. 33 ???????????????????????? (4) ????????????????????????????????????? ?????????????????????????????????????????? ??????????????????????????????????????????????????????????????????????????????????????????????????????????????? ?????????????????????????????????????????????????????

34. 34 ????????????????????????????????? ??????????? multi-center ??????????????????????????????????????????????????????????????????????????????????????????????????? ??????????????????????????????????????????????????? ?????????????????????????????????????????????????????????????????????????? ?????????????????????????????????????????? ???????????????????????????????????????????????????????? ????????????????????????????????????????????? ???????????? throat swab ???????????? (??????????????????????????????????????????????????)

35. 35 ????????????????????????????????? ????????????????????CCI ??????????????????????????????????????????? ???????????? OPD card ???????????????????????? CCI ?????????????????????? ?????????????????????????????> Datafax ??? scanner

36. 36

37. ???????????????????????????????

38. ???????????????????? ??????????????????

39. ????????????????????????????????? (ILI)

40. ????????????????????????????????? (???????????????????????? 7 ????????)

41. ??????????????????????? ???????????????

42. 42 ??????????????????????????????????????????? (1) ???????????????????????????? ??????????????????????????????????????? ???? ???????????????????????????????????????? ????????????????????????????????????? ??????????????????????????????????????????????????????????? (Worst case scenario) ???? ?????????????????????? ??????????????????????????????????????????????????????? 1:4-1:5 ?????????????? ??????????????????????????????????? ???? ?????????????????????????????????????????????? ????????????????????????????????????????????

43. 43 ????????????????????? ?????????????????????? ?????????????????????????????? ???????????? ????????????????????????????????????????? ??????????????? ????????????????????????? ????????????????????? ??????????????????????????????????????????????? ?????????????????????????????? ???? ??????????????????????????????????????????????? ?????????????????????????????????????? ??????????????????????????????????????????? (2)

44. 44 ???????????????????????????????????????????????????????? ??????????????????????????????? ???????????????????????? ????????????????????????????? ?????????????????????????? ??????????????????????????????????? (co-morbidity) ???????????????????? ?????? co-morbidity index ?????????????????????????????????????????????????????? ??????????????????????????????????????????? (3)

45. 45 ????????????????????? ??????????????? ??????????????????????????? ?????????????????????????????????????????????? ???????????????????????????????????????????????????????????????????????????? ???? ?????????????????????????? ???????????????????????????????????????????? ????????????????????????? (???????? ??????????????????????) ???????????? ???????????????????????????????????????????????????? ???? ???. ???????????????????????????????? ???????????????????????????????????????????????? ???????????? ??????????????????????????????????????????? (4)

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