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Drug Abuse Treatment of 32

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


Outline of Talk

• Background

• Model of maintenance therapy for opiate addiction and HIV prevention

• Results – methadone

• Results – buprenorphine

• Other relevant issues


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


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


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)


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


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


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!


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?


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


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


UninfectedPersons, X(t)

InfectedPersons, 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]

t

Number of InfectedPersons at Time t, Y(t)

Simplest epidemic model


Schematic of dynamic model

Non-IDUNon-IDU

HIV+Non-IDU

AIDS

IDU

IDU, MMT

IDU,HIV+

IDU,AIDS

IDU, MMTHIV+

IDU, MMTAIDS

Not Infected HIV-Infected AIDS

IDUs

MethadoneMaintenanceTreatment

Non-IDUs


Uninfected IDUs, Not in Treatment

X1(t)

(t)

(t) (t)

(t)

(t)

(t) (t)

(t)

(t)

(t)

(t)

(t)

(t)

(t)

(t)

Uninfected IDUs,In Treatment

X4(t)

UninfectedNon-IDUs

X7(t)

HIV-Infected IDUs, Not in Treatment

X2(t)

HIV-Infected IDUs,In Treatment

X5(t)

HIV-Infected Non-IDUs

X8(t)

IDUs with AIDS, Not in Treatment

X3(t)

IDUs with AIDS,In Treatment

X6(t)

Non-IDUs with AIDS

X9(t)

AID

S D

eaths

j(t)j=1

9

j(t)j=1

9

j(t)j=1

9


)()())()()(()()()()()(9

11111141714417711 ttXtttXtXttXttX

jj

)()())()()(()()()()()(9

111222252825528822 ttXtttXtXttXttX

jj

))()()(()()()()()()( 33336393226639933 tttXtXtXttXttX

etc...

Size of compartment 7(general population)

Migration rates

Size of compartment 4(IDUs in MMT)

Size of compartment 1(IDUs not in MMT)

Mortality rate

Maturation rate

New HIV Infections

Change in number ofIDUs not in MMT

Epidemic modelequations


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


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


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


Cost and quality of life

Uninfected HIV-

Infected

AIDS

Untreated IDUs

$3,850 (.80)

$8,653 (.72)

$36,401 (.42)

MMT $8,261 (.90)

$18,806 (.81)

$40,812 (.48)

Non-IDUs $1,210 (1.00)

$6,013 (.90)

$33,761 (.53)


Results: Methadone maintenance

High-Prevalence Community

Low-Prevalence Community

Methadone cost $17.0 m $4.8 m

Net cost $10.9 m $3.3 m

QALYs gained 1300 301

CE ratio $8,200 $10,900


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


Cost of 100 new slots ($1000’s) High-Prevalence

Community Low-Prevalence

Community

Methadone 4538 4538

HIV care – IDUs -970 -540

HIV care – non-IDUs -321 -323

Other health – IDUs -569 -796

Other health – non-IDUs 241 242

Total cost 2919 3121


Benefits of 100 new slots ($1000’s)

High-Prevalence Community

Low-Prevalence Community

Infections averted – IDUs 51 20

Infections averted – non-IDUs 19 12

QALYs – IDUs 149 81

QALYs – former IDUs 28 46

QALYs – never IDUs 178 160


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


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


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


CE ratios: Buprenorphine maintenance

$5/Dose $15/Dose $30/Dose

All Slots incremental:

High-prevalence community $10,800 $20,500 $35,000

Low-prevalence community $14,000 $26,000 $44,200

5% Net Expansion:

High-prevalence community $14,000 $35,100 $66,700

Low-prevalence community $17,700 $44,500 $84,700


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


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


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


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)


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

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drug addicts ny times

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