Shifting the demand curve: the microeconomics of low barrier buprenorphine treatment.
Working in the urban primary care
safety net for nearly two decades, I've personally witnessed the growing
opioid dependence problem. Hell, as a physician who trained in the era of "pain as the 5th vital sign" I had a role in creating the problem. Fortunately, I've also played an active role in the response to
this public health crisis and have been providing medication assisted opioid treatment for the past several years. One of my latest projects has been working on an innovative treatment model to deliver "low barrier" buprenorphine in unique settings, including homeless support centers and needle exchange programs. This idea is supported by data out of Boston and San Francisco that by meeting people in a non-judgmental way in a setting that removes as many hurdles as possible you see similar treatment retention and engagement rates as with traditional chemical dependency programs and at lower cost. Further, by reducing heroin use, providing naloxone for overdose, and bridging care for complications of drug use such as infections, HIV, hepatitis C, and mental illness, the hope is to improve a wide array of health outcomes for this needy population.
While the factors that determine whether an
individual falls into chemical dependency are complex and incompletely understood,
the behaviors of those who are fully afflicted with heroin addiction are rather
simple to predict and the principles of microeconomics are especially suited to
an analysis of the situation.
Opiate withdrawal is intensely
uncomfortable and for an addict words cannot describe what it is like to be
“dope sick.” As such, an addict will do almost anything to continue to use
heroin every 8 hours in order to avoid going through the experience of
withdrawal. As such, the demand for heroin among addicts can be considered
highly "inelastic" or insensitive to price. Most of the people I have worked with spend their entire days
working to secure a steady supply of heroin, to the exclusion of food, shelter,
safety, medical care, court appearances, medical appointments, and social
services. For an individual, the demand is unwavering (required every 2-6 hours)
and the quantity demanded increases over time.
Historically,
attempts to address the problem of opiate addiction have focused on controlling
the supply of heroin and offering a substitute in the form of methadone to
prevent withdrawal. Attempting to control the supply of heroin with
interdiction would have the effect of shifting the supply curve to the left by
creating risk and raising the opportunity cost to the supplier. However, given
the inelastic nature of heroin demand and relative insensitivity to price among
addicts, even if such controls were successful, we would expect little impact
on the amount of heroin consumed. In fact, the impact is primarily on the
behaviors employed by addicts to continue to obtain heroin.
The
other way that society has attempted to affect the problem of opioid dependence
is to somehow make the demand more elastic and shift the heroin demand curve rightward
by offering an acceptable substitute in the form of methadone. Methadone is a
long acting opiate which can be taken orally and can stave off the opiate
withdrawal syndrome for at least 24 hours. Indeed, studies have shown this to
be effective in getting addicts to stop using heroin.[i] This is
provided in a medical setting and is covered by medical insurance. By giving
the addict an acceptable substitute, heroin demand becomes more cost
sensitive, and perhaps in combination with shifting the supply curve rightward,
we see more of a change in behavior.
Unfortunately,
methadone itself is a risky drug. It has unpredictable pharmacokinetics, has
many drug interactions, can easily cause overdose, and stopping it is just as
difficult as stopping heroin. As such, methadone dispensaries are very tightly
regulated by the federal government. Most people in treatment must show up
daily to the dispensary within a narrow window, take their dose while directly
observed, and are subject to discharge from treatment for failure to comply
with any of dozens of rules. Further, as treatment centers for people with
serious lifelong chemical dependency problems, methadone treatment centers have
become well known foci for drug dealing and criminal behavior. Only a minority of
counties in Washington state have a methadone dispensary[ii]. These factors
create barriers for and effectively increase the marginal cost of methadone as
a heroin substitute therefore imposing a limited effect on the heroin demand
curve.
But
what if there was a way to reduce the marginal cost of a heroin substitute? From
a microeconomics perspective, a more attractive alternative to heroin ought to
alter the behavior of addicts.
Buprenorphine
(Suboxone™, Subutex™) was FDA approved for opiate
dependence in 2002. This mixed opiate agonist/antagonist has an extremely high
affinity for the opiate receptor. It binds to and rapidly saturates and
stimulates the opiate receptor. It ameliorates the opiate withdrawal syndrome, and
because it has a higher affinity and longer half life than heroin it blunts the
effect of heroin use on top of it. It has a ceiling effect on respiratory
suppression and its pharmacokinetics and interactions are much safer than
methadone. For these reasons, buprenorphine is less tightly controlled by the
federal government and can be prescribed in an ordinary office setting after
completion of a required training and certification program.
Early
in the history of buprenorphine use, chemical dependency counseling was a
requirement for its use and many health insurances did not cover it or required complicated
prior authorization. Practically speaking, most prescribers had a low threshold
for discontinuing the medication for patients who continued to use other drugs, or missed appointments, etc. As a result, those who most clearly benefitted were the more
highly functional opiate addicts, those early in the course of their disease, or
who’d established sobriety previously through incarceration or methadone, and those
with housing and jobs. For the most challenging patients, the ones at highest
risk for overdose and hospitalization, who could not keep appointments or
adhere to requirements of treatment, the barriers and costs for this new therapy
were still too high to affect the demand curve.
As
the opioid epidemic became more widespread, and as prescribers grew more
comfortable with the use of buprenorphine, regulations have been
relaxed and it has become easier to promote the use of the medication in
leveraging early abstinence, even when we expect less than perfect compliance
and follow up.
In the
summer of 2018, a cluster of newly diagnosed HIV cases was identified in North
Seattle among the heterosexual homeless population[iii]. Further
investigation suggested a hyperlocal focus of injection drug use and commercial
sex work as the key risk factors for transmission and an opportunity for
intervention.
There
are two clinics located within ½ mile of our target population which offer
buprenorporphine treatment for opioid dependence, one a mental health services
organization and another a federally qualified community health clinic. Despite
their stated mission to see underserved and uninsured people, very few from this
target population have been engaged in care in these places. There are several
potential reasons for this. Those who are eligible for Medicaid or Medicare
must have that in place before being seen or before being set up with sliding
scale payment. New patients must make an appointment and arrive on time for
such an appointment in order to be seen, or wait an indeterminate period of
time in order to be seen. Finally, although relative close by, these clinics
are located in areas rarely frequented by our target population and presenting
to either of these clinics for an appointment is a planned, willful act in an
unfamiliar area. For a population with extremely limited resources and skills
and several competing immediate needs, all of this has proven to simply raise
the barrier to treatment and the effective cost of treatment to a prohibitive
level.
As a
pilot program, we are now bringing treatment to them. In collaboration with a
homeless services organization, the Aurora Commons, and Sound Mental Health, with financial support from a Washington State Health Care Authority
grant, we are providing substitutes for heroin at lower cost than has ever been
available to people who are the most seriously afflicted with opiate addiction,
who have historically had the least ability to access treatment – the unstably
housed, commercial sex workers, those frequently incarcerated. We are working
in the areas where these people live and congregate, talking with them about
treatment alternatives, and if they are interested, starting them on therapy. In
addition to medication, we have chemical dependency counselors on staff and
case management available. We have the ability to refer into inpatient
treatment and access further medical care for the complications of their drug
use. None of this is required for access to medication. My team only started 3 months ago now and anecdotally we have had a handful of successes; this is thrilling because this is such a difficult population to treat. As mentioned, published data
from Boston[iv] and San
Francisco[v] has been encouraging, and we hope to present similar findings in time.
[i] Methadone
maintenance therapy versus no opioid replacement therapy for opioid dependence.
Mattick RP, Breen C, Kimber J, Davoli M
Cochrane Database Syst Rev. 2009
[ii] University
of Washington Alcohol and Drug Abuse Institute
[iv]
Chatterjee A, et al. Shelter-based opioid treatment: increasing access to
addiction treatment in a family shelter. Am J Public Health. 2017;107(7):1092–4
[v] Carter
J, Zevin B, Lum PJ. Low barrier buprenorphine treatment for persons
experiencing homelessness and injecting heroin in San Francisco. Addict Sci
Clin Pract. 2019 May 6;14(1):20.
Comments
Thank you very much for doing this and sharing your findings.