Influenza vaccine costeffectiveness in elderly with chronic illness

1
Influenza vaccine cost-effectiveness in elderly
with chronic illness

• Potjaman Siriarayapon, Jongkol Lertiendumrong,
  Benjawan Raluek, Vichan Pawan
• FETP, IHPP

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
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
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)

Has RCT in Bangkok and result showed
cost-effectiveness of the vaccine
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
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
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
Study population

• People age gt65 years who stayed in Muang district
  and was diagnosed by doctor as
• COPD
• Asthma
• DM
• CRF
• Stroke
• Cancer with chemotherapy
• Elderly gt65 years who was diagnosed by doctor
  with acute MI

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
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

Will prioritize those admitted in 2007-2008
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 1.51
• Sample size two arms 1160
• Adjusted for 20 loss F/U 1400

Rungnirand Praditsuwan, et al., J Med Assoc
Thai, 2005 MMWR Prevention and Control
of Influenza, 2006, p. 7
RCT among elderly in Thailand urban community
in 2005,
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 1.51
• Sample size two arms 493
• Adjusted for 20 loss F/U 600

RCT in Argentina in 2001 (FLUVACS study)
In the case that could not have enough ac. MI,
include recurrent chronic MI
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
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
Data collection

• Variables
• Tool
• Methods

18
Variables (1)

• Exposure Influenza vaccine, from document and
  interview
• Outcome data
• Influenza incidence
• Hospitalization from all medical conditions
• Death from all cause

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
Variables (3)

• 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

See next slide
Charlson Comorbidity Index
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
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
Variables (5)

• Potential confounders COPD
• Severity of COPD (FEV1)
• Steroid used (systemic, inhale)
• Long acting-inhale ß2 agonist

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
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
Data collection methods

• Enrollment
• Place at health center
• Period 1-2 months
• F/U of participants
• Telephone every 2 weeks
• If loss F/U gt 4 weeks, research assistant will
  visit their house, will exclude if can not
  contact for gt 6 weeks

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 95CI

28
Budget estimation

• 10 million baht

29
????????????????????????????????????????

• ??????????????????????????????????????????????????
  ????? ????????????????????????????????????????????
  ???????????????????????????
• ????????????????????? ????????????????????????????
  ???????? 2551 ????????????????????????????????????
  ?????
• ????????????????????????????????????????
  ??????????????????????????????????????????????????
  ????????????????

30
???????????????????????? (1)

• ?????????????????????????????????????????????????
• ??????????????????????????????????
  ??????????????????????????????????
  ???????????????????????????????????
• ???????????????????????????????????
• ????????????????????? 2 ???? ???????????????????
  ??????????????????????????????????????????????????
  ?????????
• ??????????????????????????????????????????????????
  ???????????????????? ?????????????????????????????
  ????????????

31
???????????????????????? (2)

• ????????????????????????????????????
  ?????????????????????????????????????????
• ???????????????????????????????????????????????
  ???????????????????????????????????
• ??????????????????????????????????????????????????
  ???????????????
• ??????????????????????????? ??????????????????????
  ?????
• ????????????????????????????? ????????????????????
  ????????????? pilot study

32
???????????????????????? (3)

• ????????????????????
• ???????????????????????????????????????????????
  ?????????????????????????? (?????? 30-40)
• ????????????????????????/ ????????????????????????
  ??????
• ??????????????????????????????
• ????????????????????? ????????????????????????????
  

(?????????????????????????????????????????????????
?????????????????? ??????????????? ???????????????
?????????????????????????? ??????? 60-64 ??)
33
???????????????????????? (4)

• ?????????????????????????????????????
• ??????????????????????????????????????????
• ??????????????????????????????????????????????????
  ??????????????????????????????????????????????????
  ??????????? ??????????????????????????????????????
  ???????????????

34
?????????????????????????????????

• ??????????? multi-center
• ??????????????????????????????????????????????????
  ?????????????????????????????????????????????????
• ??????????????????????????????????????????????????
  ? ????????????????????????????????????????????????
  ??????????????????????????
• ??????????????????????????????????????????
  ??????????????????????????????????????????????????
  ??????
• ?????????????????????????????????????????????
  ???????????? throat swab ????????????
  (?????????????????????????????????????????????????
  ?)

35
?????????????????????????????????

• ????????????????????CCI
• ???????????????????????????????????????????
  ???????????? OPD card ????????????????????????
• CCI ?????????????????????? ???????????????????????
  ??????gt
• Datafax ??? scanner

36
(No Transcript)
37
???????????????????????????????
38
???????????????????? ??????????????????
??????????????????????? 2550-2551
39
????????????????????????????????? (ILI)
?????????? throat swab 92 ??? (64.8)
?????????????????? 13 ??? ?????????? throat
swab 16 ??? (66.7) ?????????????????? 2 ???
40
?????????????????????????????????
(???????????????????????? 7 ????????)
41
??????????????????????? ???????????????
42
??????????????????????????????????????????? (1)

• ???????????????????????????? ?????????????????????
  ?????????????????? ???? ??????????????????????????
  ?????????????? ???????????????????????????????????
  ??
• ??????????????????????????????????????????????????
  ????????? (Worst case scenario) ????
  ?????????????????????? ???????????????????????????
  ???????????????????????????? 14-15
• ?????????????? ???????????????????????????????????
  ???? ????????????????????????????????????????????
  ?? ????????????????????????????????????????????

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

• ????????????????????? ??????????????????????
  ??????????????????????????????
• ???????????? ?????????????????????????????????????
  ????
• ??????????????? ?????????????????????????
  ????????????????????? ????????????????????????????
  ???????????????????
• ?????????????????????????????? ????
  ???????????????????????????????????????????????
  ??????????????????????????????????????

44
??????????????????????????????????????????? (3)

• ??????????????????????????????????????????????????
  ?????? ???????????????????????????????
  ????????????????????????
• ????????????????????????????? ????????????????????
  ??????
• ???????????????????????????????????
  (co-morbidity) ???????????????????? ??????
  co-morbidity index
• ??????????????????????????????????????????????????
  ????

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

• ????????????????????? ???????????????
• ???????????????????????????
• ??????????????????????????????????????????????
• ??????????????????????????????????????????????????
  ?????????????????????????? ????
  ??????????????????????????
• ????????????????????????????????????????????
  ????????????????????????? (????????
  ??????????????????????)
• ???????????? ?????????????????????????????????????
  ??????????????? ???? ???. ????????????????????????
  ????????
• ????????????????????????????????????????????????
  ????????????

46
?????????