Cost Effectiveness of Maintenance Treatment for Heroin Addicts

1. Cost Effectiveness of Maintenance Treatment for Heroin Addicts Professor Margaret Brandeau Department of Management Science and Engineering with Greg Zaric, U. Western Ontario Paul Barnett, Palo Alto VA

2. Outline of Talk • Background • Model of maintenance therapy for opiate addiction and HIV prevention • Results – methadone • Results – buprenorphine • Other relevant issues

3. Introduction • 1-1.5 million IDUs in U.S. • High prevalence of HIV among IDUs (5-40%) • One-third of new HIV cases due to IDUs • New laws require treatment instead of jail time

4. Methadone maintenance • Addicts receive daily doses of methadone • Methadone treatment slots only for 15% of IDUs • Average wait to enter treatment is 6 months • Expansion of MMT is controversial • Many health care sponsors (e.g., Medicaid) do not cover MMT • Eight states prohibit methadone

5. Methadone in the news • “Mayor Wants To Abolish Use of Methadone” • “Methadone: A Cure or an Addiction?; Giuliani Is Right” • “Few Successes to Back Mayor’s Methadone Limits” (NY Times, 8/25/98) • “Federal Proposal Would Provide Methadone to More Drug Addicts” (NY Times, 9/29/98)

6. Buprenorphine maintenance • Buprenorphine may be safer than methadone • Low abuse potential; daily dispensing not required • Less effective than methadone in reducing risky behavior • Widely used in France • Not approved for maintenance treatment in U.S. • No price set

7. Potential benefits of maintenance treatment • Reduced HIV transmission • Reduced mortality and comorbidities associated with injection drug use • Increased quality of life • Reductions in cost of HIV care and other health care • Reductions in cost of social programs

8. Potential drawbacks of maintenance treatment • Maintenance treatment is costly - $5,000+ / year • HIV-infected individuals in maintenance treatment are more likely to receive expensive HIV treatment • Maintenance treatment does not induce complete abstinence from risky behavior • Average stay in treatment is 2 years • 90% of those leaving treatment resume injection drug use!

9. Policy questions What is the cost effectiveness of expanding existing methadone maintenance programs in the U.S.? What would be the cost effectiveness of buprenorphine maintenance treatment in the U.S., as a function of its price?

10. Methods • Dynamic model of HIV transmission • Two scenarios: High (40%) and low (5%) HIV prevalence among IDUs • Assumed modest increases in maintenance treatment capacity • Methadone: 10% increase • Buprenorphine: 10% increase • All slots incremental • 5% net expansion

11. Methods (cont.) • Estimated total costs and health benefits over a 10-year time horizon (societal perspective) • Costs: all health care costs • Benefits: QALYs gained • Calculated incremental CE ratios

12. Simplest epidemic model Uninfected Persons, X(t) Infected Persons, Y(t) dY/dt = aY(t)[N + 1 - Y(t)] where: Y(0) = 1 a = sufficient contact rate X(t) + Y(t) = N + 1 Y(t) = [N+1]/[1 + Ne-a(N+1)t] Number of Infected Persons at Time t, Y(t) t

13. Not Infected HIV-Infected AIDS IDU IDU, HIV+ IDU, AIDS IDUs Methadone Maintenance Treatment IDU, MMT IDU, MMT HIV+ IDU, MMT AIDS Non-IDUs Non-IDU Non-IDU HIV+ Non-IDU AIDS Schematic of dynamic model

14. 9 j(t) j=1 9 j(t) j=1 9 j(t) j=1    IDUs with AIDS, Not in Treatment X3(t) Uninfected IDUs, Not in Treatment X1(t) HIV-Infected IDUs, Not in Treatment X2(t)   (t) (t) (t) (t) (t) (t)    (t) (t) (t) Uninfected IDUs, In Treatment X4(t)  HIV-Infected IDUs, In Treatment X5(t) IDUs with AIDS, In Treatment X6(t)  AIDS Deaths (t) (t) (t) (t) (t) (t)  Uninfected Non-IDUs X7(t)  HIV-Infected Non-IDUs X8(t) Non-IDUs with AIDS X9(t)    

15. Epidemic model equations Size of compartment 4 (IDUs in MMT) Size of compartment 7 (general population) Size of compartment 1 (IDUs not in MMT) Migration rates Maturation rate New HIV Infections Change in number of IDUs not in MMT Mortality rate etc...

16. Model inputs • Drug injection behavior (in/out of treatment) • Sexual behavior • HIV transmission rates • HIV progression rates • Mortality rates • Quality-of-life estimates • Cost per maintenance treatment slot • All other health care costs

17. Methadone assumptions • Methadone maintenance cost: $5250/IDU/year • Methadone maintenance effectiveness: • 80% reduction in injection frequency • 70% reduction in sharing • 65% annual retention rate • 3.5% annual graduation rate

18. Other data • Non-HIV death rates Untreated IDUs – 3% IDUs in MMT – 1.13% Non-IDUs – .14% • Progression rates from HIV to AIDS Untreated IDUs, and non-IDUs – .0087 IDUs in MMT – .0082

19. Cost and quality of life

20. Results: Methadone maintenance

21. CE of other HIV interventions • HIV treatments (cost/QALY gained) • PCP prophylaxis: $16,000 • MAC prophylaxis: $35,000-$74,000 • CMV retinitis prophylaxis: $160,000 • HIV prevention • Post-exposure prophylaxis: $37,000 after occupational exposure; $6,300 after sexual exposure • Incr. condom use among high-risk women: $2,000 • Skills training for gay men: Cost saving

22. Cost of 100 new slots ($1000’s)

23. Benefits of 100 new slots ($1000’s)

24. Results of sensitivity analysis MMT cost effective even if: • New slots are twice as costly and half as effective as existing slots • No reduction in quality of life for IDUs • IDUs receive a quality-of-life adjustment of zero • Only life years are measured

25. Conclusions: Methadone maintenance • Expansion of methadone maintenance treatment is cost effective relative to commonly accepted criteria • Significant benefits of methadone maintenance programs accrue to non-IDUs • Barriers to methadone maintenance may restrict access to a cost-effective medical intervention

26. Buprenorphine assumptions • Buprenorphine maintenance cost: • $5700, $9400, $14,900/IDU/year • Buprenorphine maintenance effectiveness: • 73% reduction in injection frequency • 64% reduction in sharing • 65% annual retention rate • 2.8% annual graduation rate

27. CE ratios: Buprenorphine maintenance

28. Results of sensitivity analysis • Buprenorphine cost effective if: • High value assigned to treatment benefit • Low value for treatment benefit, low price • Buprenorphine not cost effective if: • No value assigned to LYs of IDUs or those in treatment, and high price • Many IDUs switch from MMT to buprenorphine

29. Conclusions:Buprenorphine maintenance • At $5/dose, buprenorphine maintenance treatment is cost effective • Buprenorphine is cost effective at $15/dose only if its adoption does not lead to a decline in MMT • Buprenorphine is not likely to be cost effective if the price is $30/dose

30. Other relevant issues • Reductions in cost of social programs • Reductions in spread of other diseases (Hepatitis B and C, TB, other STDs) • Networks of IDUs • Characteristics of IDUs enrolled in the incremental treatment slots • Legal, philosophical and moral concerns

31. Update • MMT programs • Expansion in some areas • Budget cutbacks in some states • “Wait for Methadone Puts Hundreds of Lives on Hold” (Seattle PI, 3/17/03)

32. Update • Buprenorphine approved by FDA in October, 2002 • Schedule III drug • Prescribed in doctor’s office • 30-day prescriptions • Cost/dose ~ $5 • Medicare coverage: on a state-by-state basis