Evidence-based public health

1. Evidence-based public health Making decision about health services Fellow 52 (EBM course): 26 Oct 10

2. outline • Why focus on decision making ? • How the decision is made ? • Analytic tools and approaches to enhance the uptake of EBPH • Examples and shared experience • Assignment

3. Why focus on decision making ? • An enormous number of decisions is made • Under limited of health care resources

4. How the decision is made ? Values needs evidence OBDM –opinion-based decision making resources EBDM –opinion-based decision making Increasing pressure

5. Evidence- based public health intervention • Any intervention to improve the public health must act on at least one of the health determinants of health Social env Physical env genetic Health status Biological env Health services

6. Four types of intervention • Health care • Educational • Social and community action • legislative

7. Health care • Effect population health > individual • Evidence of effectiveness of these intervention should meet the same requirement • Systematic review and RCT: gold standard

8. educational • Currently subject to less rigorous scrutiny then health care intervention • The Campbell Collaboration

9. Social and community action • Difficult to evaluate in RCT • Unit of intervention = community • Cautious to interpreting the results

10. The use of legislative power to improve the public health • Pragmatic about the influence of evidence during the decision making process • Public health profession VS politician

11. Analytic tools and approaches to enhance the uptake of ebph • What is the size of the public health problem? • Are there effective interventions for addressing problem? • What information about the local context and this particular intervention is helpful in deciding its potential use in the situation at hand? • Is a particular program or policy worth doing and will it provide a satisfactory return on investment, measured in monetary terms or in health impacts?

12. Public health surveillance • On going systematic collection, analysis and interpretation of specific health data • Integrated with the timely dissemination of these data to responsible person • Regularly evaluate the effectiveness of the use of the disseminated data • Exp: lead level in blood in the US population • used as the justification for eliminating lead painting and gasoline • Exercise: Identify the public health surveillance systems in your workplace and discussion about the systems, strength, weakness and possibility to improve

13. Systematic reviews and evidenced-based guidelines • One of the most useful sets of review for public health intervention: • the guide to community preventive services (http://www.thecommunityguide.org) • The quality of systematic review articles: see checklists • the local context condition

14. Cost-effectiveness analysis (CEA) • Cost-utility analysis (CUA) • Cost-benefit analysis (CBA) Economic evaluation

15. Major difference of these analysis

16. Economic evaluation: others Sensitivity analysis Optimization of resource allocation

17. Participatory approach Promise communities in EBPH Stakeholders Three groups: program operations : those affected by the program : primary users of the evaluation

18. Case study 1: กองทุนทันตกรรม Values needs evidence Evidence: unit cost for specific service Papers: Thai and other countries Appraisal: methods and context : main papers Analytic tool: Sensitivity analysis Present monetary value Application: based on these information resources

20. Case study 2: resource allocation • Resource allocation for caries control program • in school dental health services

21. nalysis of resource allocation in health care A The distribution of factors of production such as money, plant and equipment, and skilled labor among alternative uses ( Shim JK, Siegel JG, Dictionary of Economics, 1995 ) Resource allocation

22. General objective • To identify optimal level and mix of three basic dental services (sealant and filling for permanent teeth and extraction of primary teeth) provided to primary school children under two different dental settings; hospital-based and mobile dental clinics under specified resources, service need and setting preference constraints

23. Developing LP model Examples of developing model A company produces 2 products: A and B Resource requirements are summarized in table Resources available Space 1,500 m2 Material 1,575 kg Total hour 420 minutes

24. Resource data • Because of rigidities in hospital budget allocations, separate resource constraints were identified. Provider time Assistant time Material cost Capital depreciated cost Supportive cost • The mobile clinic included 2 dental nurses, 1 dental assistant and 1 driver • The average levels of service provision per school visit 30 sealants, 20 fillings or 50 extractions

25. Need data • Minimum cases of service need: hospital policies Sealant : all caries free first permanent molars of grade 1 children Filling and extraction : urgent cases • Urgent fillings defined as caries in permanent teeth without history of continuous pain or abscess could be restored by amalgam filling. • Urgent extractions defined as severe caries in primary teeth which caused difficulty in chewing and cleansing.

26. Preference data • Setting preference: parent’s WTP WTP hospital service VS WTP mobile service Example: WTP SH = 200, WTP SM = 220 Setting preference for sealant mobile > sealant hospital Setting preference for sealant = mobile • Benefit of the service = adjusted WTP of each service Adjusted for SES, perception of child oral health, experience of three basic dental services, experience of hospital or mobile dental clinic

27. Data analysis • Solver linear programming module in Microsoft excel • The output of the analysis is the level of services to be provided for each service setting

28. Results Optimization condition of service-mix and WTP produced by service from different model Model 1:included all constraint, Model 2: included resource, Model 3: included resource and need, Model 4: actual service

29. Exercise Sealant program

30. Sealant program values evidence What do you think about sealant situation in local context? resources

31. Review of sealant retention in Western Countries M1 = First permanent molar M2 = second permanent molarAll = All permanent teeth, premolar and molar Rationale

32. Review of caries on sealed surface in Western Countries M1 = First permanent molar M2 = second permanent molarAll = All permanent teeth, premolar and molar Rationale

33. Review of sealant retention inThailand M1 = First permanent molar Rationale

34. Review of caries on sealed surface in Thailand M1 = First permanent molar Rationale

35. Sealant in Mobile Dental Clinic Sealant in Mobile Dental Clinic Transition analysis of Retention and Caries

36. Summary of findings Discussion • This study has lower retention rate of sealant and higher caries rate on sealed surface compared to western countries, although slightly better result than other Thai studies • 2. Probability of losing of full retention was high in the first 6 months, approximately 1/3 • The rate of this loss become less at around 12-25% in subsequence cycle • However, the transition probability toward caries is small (2-4%) • 3. After partial loss, the probability of getting caries remarkably increased to 11-20%, whereas, the probability of total loss turning to caries is around 2-5% From Descriptive analysis From Markov process

37. Discussion Summary of findings(cont.) • 4. Determinants of sealant retention includes moisture control, assistant and cooperation of children • 5. Partial loss lead to caries within 6 months with a rate 2.8 times higher than total sealant loss and 6.5 times that of among full retention group From Life table From Transition OR Discussion

38. Sealant program in local context • What do you think about sealant program situation in your area? • Is it effective? • Is it worth to do? Good VS Harm • Any data or information do you need to answer this problem?