Cost effectiveness of echocardiographic screening for RHD

Transcription

1 Cost effectiveness of echocardiographic screening for RHD Andrew Steer MBBS BMedSc MPH FRACP PhD Centre for International Child Health University of Melbourne Melbourne, Australia

2 Cost of disease Cost and benefit of screening

3 Outline 1. Levels of prevention of RHD 2. The costs of RHD 3. Existing cost effectiveness data for prevention of RHD 4. Screening: costs and savings 5. Future directions

4 Control of RHD

5 Susceptible host Primordial prevention GAS infection Primary prevention ARF Secondary prevention No RHD RHD RHD morbidity (CCF, AF, IE, Stroke) Death Clinical management Heart failure medication Surgery Anticoagulation

6 Susceptible host Primordial prevention GAS infection ARF No RHD RHD RHD morbidity (CCF, AF, IE, Stroke) Death

7 Primordial prevention Sulfanilimide Penicillin Incidence of rheumatic fever in Denmark

8 Primordial prevention The dramatic reduction in ARF and RHD witnessed in the industrialized world in the last century was the result of improvements in hygiene, access to medical care, crowding. The corollary, therefore, is that these improvements have not been afforded to people in developing countries or indigenous people in wealthy countries.

9 Susceptible host GAS infection Primary prevention ARF No RHD RHD RHD morbidity (CCF, AF, IE, Stroke) Death

10 Primary prevention Treatment of group A streptococcal pharyngitis in a timely and proper manner to prevent rheumatic fever GAS infection ARF Primary prevention

11 The Warren Air Force Base study Cheyenne Wyoming 8000 air force trainees month study Randomised trial of penicillin for the treatment of exudative tonsillitis (80% had GAS) Outcome measure rheumatic fever

12 1634 men No treatment Penicillin G 804 men 798 men 17 cases ARF 2 cases ARF RR 0.12 (95% CI )

13 Primary prevention 8 trials between in Air Force bases* RR 0.32 (95% CI ) *Robertson KA et al. BMC Cardiovasc Disord. 2005

14 Primary prevention Principles of treatment to achieve primary prevention of rheumatic fever: 1. Eradicate pharyngeal carriage 2. Penicillin is the drug of choice 3. Penicillin must be used for 10 days at proper doses 4. Penicillin may be given up to 9 days after the onset of pharyngitis

15 Primary prevention in developing countries It may work on an air force base for soldiers but Barriers to implementation in a developing country: Low priority in attending health care facility with a sore throat Poor access to medical facilities Shortage of skilled staff at primary health care level Poor access to microbiologic facilities to diagnose GAS pharyngitis Unreliable supply of penicillin Compliance

16 Community or school based programs Intensive sore throat surveillance Identify children with GAS (either by clinical signs or swab) Penicillin treatment (+/ treatment of family)

17 53 schools 27 schools with a sore throat clinic n=43, control schools n=43, cases 55 per 100,000 RR 0.79 (95% CI ) 29 cases 67 per 100,000

18 Susceptible host GAS infection ARF Secondary prevention No RHD RHD RHD morbidity (CCF, AF, IE, Stroke) Death

19 Secondary prevention The regular delivery of antimicrobial prophylaxis to patients with a past history of rheumatic fever with the aim of preventing further attacks of rheumatic fever. ARF Secondary prevention RHD RHD morbidity (CCF, AF, IE, Stroke)

20 Secondary prevention Recurrent ARF leads to worsening of RHD RF Working Party, Circulation year follow up study of ARF patients 60% Secondary of patients with prevention ARF recurrences prevents had chronic ARFRHD cf. 34% of those without recurrences had RHD Multiple studies from US RR 0.45 (95% CI 0.22 to 0.92) Secondary prevention prevents worsening of RHD Tompkins, Circulation % of RHD patients lost the murmur of MR after up 9 years of follow up cf. 70% on secondary prophylaxis Secondary prevention prevents death Secondary prevention can lead to regression of RHD Lue, Indian Heart J % not on prophylaxis died cf. 0.6% on prophylaxis Several studies have documented that RHD regresses in 50% 70% of patients with RHD adherent to prophylaxis over 10 years especially mild disease

21 Secondary prevention More than just delivering BPG Recommendations for effective secondary prevention programs* Centralised Government, MOH, clinician, public health buy in Well funded in the longer term Advisory committee Prioritisation of BPG delivery within a primary/public health framework (i.e. horizontal delivery) Health education Ability to monitor disease Ability to monitor adherence Screening *National Heart Foundation of Australia 2006

22 2. The costs of RHD

23 The costs of RHD Narrow view: 1. Direct costs (patient): Mortality Transportation Laboratory costs etc. 2. Health care costs (government and community): Surgery Hospital stay Medications 3. Productivity costs: Time off work (patient) Time off work (carer)

24 The costs of RHD The broader view: * 4. Outcome related productivity costs Reduced cognition Reduced physical strength Reduced school attendance and educational attainment 5. Behaviour related productivity costs Reduced survival changes household behaviour 6. Community externalised costs Effects on people without RHD

25 What data do we have regarding cost of RHD? BRAZIL: Terreri MT et al. Resource utilization and cost of rheumatic fever. J Rheumatol 2001; 28:

26 Direct and indirect costs of RHD in 100 patients in Sao Paulo (costs in USD, data extrapolated) Total costs Mean cost/patient/yr Patient costs $607,603 $ Societal costs $1,232,564 $ *Mean annual income: $7500 (6.9%) *Annual cost to society in Brazil: $51,000,000

27 Other data: Costs of RHD are likely to vary between countries depending upon: Health care system (private vs public) Costs of medicine and monitoring Costs of surgery: Transport for surgery can be expensive e.g. $USD30,000 Fiji Australia

28 3. The cost of preventative strategies How best to measure cost effectiveness? Cost to detect one case of ARF / RHD Cost to prevent one death due to RHD Cost to detect one case compared with annual cost of RHD Cost per DALY averted What about the other broader factors?

29 3. The cost of preventative strategies

30 4. Screening for RHD

31 Screening for rheumatic heart disease Criteria for selecting a disease for screening*: 1. The disease should be an obvious burden for the individual and/or community in terms of death, suffering, economic or social costs 2. The natural course of the disease should be well known and the disease should go through an initial latent stage 3. An appropriate test is highly sensitive and specific for the disease as well as being acceptable to the person screened 4. Adequate treatment (of proven medical benefit and ethical acceptability) is available. 5. Screening followed by diagnosis and intervention in an early stage of the disease should provide a better prognosis than intervention after spontaneously sought treatment *Council of Europe, Recommendation No. R(94)11 on Screening as a Tool of Preventative Medicine. 1994

32 Screening for RHD Screening for rheumatic heart disease should not be initiated within a population unless an adequate secondary prevention program is in place to serve the detected patients.

33 Screening for RHD The latent phase of RHD: mitral regurgitation Prevalence of pure MR 100% 50% 90% 65% 40% 100% 50% Symptomatic MR disease Likelihhod of presentation 10 yrs 25 yrs 40 yrs Age Carapetis J, University of Sydney 1998

34 Screening vs

35 Cambodia: 2.2 cases per cases per 1000 Factor x 9.8 Mozambique: 2.3 cases per cases per 1000 Factor x 13.2

36 Screening by echocardiogram The Marijon study: many questions remain Mild disease: best chance of regression with secondary prophylaxis Is it real? Major issue in overtreating and over burdening already stretched health systems

37 What are the costs of screening? Not formally evaluated Essential elements: Coordinator and assistant staff Echocardiographic technicians Cardiologist(s) Echocardiogram machine(s) Ability to transport team and patients Functioning register based secondary prevention program Benzathine penicillin Functioning clinical follow up

38 What are the costs of screening? How to bring costs down Echo machines are becoming cheaper (<USD20K) Integrate screening within existing public health programs (eg school health teams) Yearly screening is not necessary (2nd 3 rd yearly) Rely less on cardiologists doing front line work, and build local capacity

39 Screening by echocardiogram There are not enough echocardiographers and cardiologists to perform screening Nurse led echocardiographic screening in a developing country (Fiji). Nurse echocardiogram screening (regurgitant jet at MV / any AR) Cardiologist review with full echo Secondary prophylaxis if RHD confirmed

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41 Nurse led echocardiography pilot in Fiji (data courtesy S. Colquhoun)

42 6 / 49 children had RHD Case Case 1 Morphology Mitral valve MR PLAX (cm) MR apical (cm) Elbow deformity, thickened AMVL Morphology Aortic valve AR PLAX (cm) AR apical (cm) Thickened & rolled leaflets Case 2 Thickened AMVL Nil Nil Case 3 Elongated chordae, thickened AMVL, tethered PMVL Nil Nil Case 4 Thickened AMVL Nil Nil Case 5 Thickened AMVL 2.2 Nil 1.4 Nil Case 6 Thickened AMVL Nil Nil Thickened leaflets

43 Cut off used for mitral regurgitant jet Number of cases detected by nurse Sensitivity 95% CI Specificity 95% CI Nurse A 1cm cm cm Nurse B 1cm cm cm Sensitivity and specificity of nurses in identifying cases of definite rheumatic heart disease as defined by study definitions (n=6), when nurses used different mitral regurgitation jet length cut offs AND presence of any aortic regurgitation as screen positive

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45 5. Future directions Further studies are needed: The economic impact of RHD The effectiveness of RHD screening The accuracy of nurse led echocardiography The cost effectiveness of RHD screening

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49 Value of good economic data: Informs public health decision making Advocacy for disease control Advocacy for vaccine development

50 Merci beaucoup pour votre attention.