Health Economics Research Centre. The cost-effectiveness of policies to reduce radon-induced lung cancer

Transcription

1 H E R C Health Economics Research Centre The cost-effectiveness of policies to reduce radon-induced lung cancer Alastair Gray Health Economics Research Centre Department of Public Health University of Oxford, UK http// Seventh National Radon Forum Dublin, 19 th November 2009

2 Introduction Radon gas is an interesting and important public health question raises economic as well as health questions Existing policies under review by WHO, EU, UK, many other countries My interest in this: As health economist interested in getting value for money in health interventions Also as a doctoral supervisor As a member of UK Advisory Group on Ionizing Radiation (AGIR) radon sub-committee As member of WHO International Radon Project As member of EU RADPAR project

3 BMJ 2009;338:a3110

4 Economic evaluation of radon prevention and remediation Rationale: radon prevention and remediation primarily about health risks/benefits: lung cancer Wide consensus in Europe, N America, elsewhere, on methodology for economic evaluation of health interventions: cost-effectiveness analysis Therefore, radon programmes potentially suitable candidates for application of same methods

5 The health economics perspective Starting point: scarce (health care) resources Objective: maximise health gain from resources Method: compare effectiveness AND cost of intervention with next best alternative Use a common unit of measurement, e.g. life years or quality adjusted life years Calculate incremental cost-effectiveness ratio net cost per unit of health outcome gained Estimate uncertainty around this Decision-makers : decide if willing to pay

6 The cost-effectiveness plane NW Existing treatment dominates New treatment more costly NE Maximum acceptable costeffectiveness ratio Costly, not very effective = not acceptable New treatment more effective but more costly New treatment less effective C Not costly, very effective = highly acceptable New treatment more effective New treatment less costly but less effective New treatment dominates SW New treatment less costly SE

7 So two uncertainties: 1) where is intervention on the plane? 2) what is willingness to pay? New treatment NW more costly NE New treatment less effective C New treatment more effective SW New treatment less costly SE

8 What might a decision-maker be willing to pay for health gain? Depends on setting/country, national income level, and budget constraint for health care Canada, about US$50,000 per life year gained UK (NICE), 20-30k per quality adjusted life year gained Rule of thumb (WHO, World Bank): Similar to Gross National Income per person. Ireland, 2008, GNI per person = US$49,590, = 33,000 So, any intervention in Ireland that gains a life year/ QALY for < 30,000 is reasonable value for money Note: not trying to value life just trying to buy as much as possible with existing budget

9 Cost-effectiveness of radon: 2 main questions 1. What is cost-effectiveness of installing preventive measures in new homes? a) In all new homes, or targeted? b) Passive measures, active measures? c) Should more be spent on inspection, enforcement? 2. What is cost-effectiveness of remediating existing homes? a. To what level of risk is it cost-effective? b. Can policies be improved, eg to increase uptake?

10 High-risk or population approach? Distribution of measured radon concentrations & radon-related deaths, UK 0.4% of homes & 4% of radon related deaths above AL 75% of radon related deaths outside radon affected areas Source: BMJ 2009

11 Basic process: spreadsheet-based model Costs Calculate costs of finding homes: Will depend on average radon level, Reference or Action level, test acceptance rate & remediation rate Calculate costs of prevention / remediation measures Calculate costs / savings of averted lung cancer cases, added life expectancy Outcomes Calculate radon level in homes before & after action Calculate lifetime lung cancer risk before & after action, from age/sex specific rates, adjusted for smoking status and competing risks Estimate life years gained: 1) Average no. of people in home 2) Mean age at lung cancer death, adjusted for sex, smoking status 3) Age/sex specific health status Calculate cost-effectiveness Estimate uncertainty around this

12 Health effects of radon: European pooling study Used individual data from 13 case-control studies of residential radon and lung cancer in 9 European countries 7,148 cases & 14,208 controls Stratified for study, age, sex, region of residence, smoking Risk of lung cancer increased by 16% (95% c.i. 5% to 31%) per 100 Bq/m 3 increase in radon, adjusted for measurement error Results consistent with a linear dose-response relation No evidence of a threshold dose Darby S, Hill D, Auvinen A, Barros-Dios JM, Baysson H, Bochicchio F et al. Radon in homes and risk of lung cancer: collaborative analysis of individual data from 13 European casecontrol studies. BMJ 2005;330:

13 Proportional increase in risk similar by age, between men and women, and for non-smokers, ex-smokers and current smokers Cumulative absolute risk of lung cancer by age 75: Bq/m 3: Never-smokers 0.41% 0.47% 0.67% 0.93% Cigarette smokers 10.1% 11.6% 16.0% 21.6%

14 Radon prevention in new homes: costs Installation of basic measures in new homes: Gas-resistant membranes c. 50% effective Air bricks in suspended floors + Sumps, pipework, if 10% of homes likely to be above Action Level + electric fans in selected homes, with capital, maintenance, replacement and running costs Medical treatment costs Anticipated savings from reducing number of lung cancer cases Likely health care costs of added life expectancy

15 Radon prevention in new homes: outcomes Primarily survival gain from averting radoninduced lung cancer cases life years & quality adjusted life-years gained Estimates derived from residential case-control studies, collated in 2005 European Pooling Study - direct estimate

16 Preventive action in all new homes in areas where 3% of homes likely to be above 200 Bq/m 3

17 Preventive action in all new homes in areas where 3% of homes likely to be above 200 Bq/m 3

18 Preventive action in all new homes in areas with varying radon levels

19 New homes: Sensitivity to changes in main parameter values of installing basic preventive action in all new homes

20 What about new homes still above the Reference Level after basic measures are installed? Involves costs of: 1) going back and testing houses 2) inviting those still above Reference level to have home remediated Refusal rate? Who pays? 3) installing better (active?) measures 4) running, maintaining, replacing active measures

21 Illustration: an area where 10% of new homes would have had radon levels above 200 Bq m 3 if basic measures had not been installed 55 tests required to find 1 home still above 200 Bq m 3 = c. 2,300 or 2, sumps/pipework will have been fitted during construction for each home requiring active measures = c. 5,500 or 6,200 Lifetime cost of active measures, including, running costs, maintenance, replacement: Approximately 1742 or 1,950 Total cost per house with active measures installed? About 10,500 or 11,800 Cost-effectiveness? Poor: c. 53,000 per QALY gained

22 Q.: Is it ever cost-effective to install full preventive measures in new homes? A.: Only in high radon levels & with lower Action Level

23 Q: Is it worth spending more on better basic preventive measures? A: It depends on how much better at what cost

24 Radon remediation in existing homes Equivalent to a screening programme: Find the homes Difficulty of finding depends on prevalence average radon level, likelihood of being over RL Need to persuade occupiers to test In UK ~ 30% accept Need to persuade those over RL to remediate: ~ 20% (based on Devon/Cornwall data) do so Not clear if homeowners actually use, maintain active measures eg electric fans, etc.

25 Inviting existing homes to test & remediate, areas where 5% of homes are over 200 Bq m 3

26 Inviting existing homes to test & remediate, areas where 5% of homes are over current Action Level

27 Q.: Is it ever cost-effective to find and remediate existing homes? A.: Only in relatively high radon levels & if Action Level is reduced

28 Existing homes: one-way sensitivity analysis, at reduced Reference Level of 100 Bq m 3

29 Existing homes: cost-effectiveness for different groups, at reduced Reference Level of 100 Bq m 3 For never smokers, remediation unlikely to be cost-effective

30 Differences may be even greater, as non smokers at lowest risk are most risk-averse Data shows action taken by homeowners found over Action Level in recent years Current smoker Non smokers All Action 153 (23%) 1075 (33%) 1228 No action 510 (77%) 2138 (67%) 2648 All Odds ratio for Action 95% c.i. P <0.01 Non-smokers significantly more likely to remediate, despite very low risk levels.

31 Conclusions New homes: basic measures everywhere Basic preventive measures good value for money in all areas Better installation/inspection may be worthwhile Active measures rarely cost-effective, careful targeting required Existing homes: new thinking required Looking for homes only cost-effective in high radon areas Low test acceptance & remediation rates a major problem Solutions? Better publicity material, local campaigns, approved builder lists, grant / loan schemes repayable on house sale, lower cost active measures- micro fans Could make radon test in all/some areas a condition of sale Vendors pay for remediation/retest, or lower price Reducing Reference Level to 100 Bq/m 3 or lower would help Finally, make more use of cost-effectiveness to evaluate all policy ideas!