IMPACT OF SUPPLY-SIDE POLICIES FOR CONTROL OF ILLICIT DRUGS IN THE FACE OF
THE AIDS AND OVERDOSE EPIDEMICS: INVESTIGATION OF A MASSIVE HEROIN SEIZURE

Evan Wood*, Mark W. Tyndall*, Patricia M. Spittal*, Kathy Li*, Aslam H.
Anis*, Robert S. Hogg*, Julio S.G. Montaner*, Michael V. O'Shaughnessy* and
Martin T. Schechter* *British Columbia Centre for Excellence in HIV/AIDS,
St. Paul's Hospital, Vancouver, BC; Department of Health Care and
Epidemiology, University of British Columbia, Vancouver, BC; Department of
Medicine, University of British Columbia, Vancouver, BC; Department of
Pathology and Laboratory Medicine, University of British Columbia,
Vancouver, BC

Correspondence to: Dr. Martin T. Schechter, Department of Health Care and
Epidemiology, University of British Columbia, 5804 Fairview Ave., Vancouver
BC V6T 1Z3; fax 604 806-9044; martin.schechter@ubc.ca

Abstract

Background: More than 93% of the nearly $500 million spent annually on
Canada's drug strategy goes toward efforts to reduce the illicit drug
supply. However, little is known about the effectiveness of this strategy.
On Sept. 2, 2000, Canadian police seized approximately 100 kg of heroin in
one of the nation's largest-ever seizures of this drug. An ongoing
prospective cohort study of injection drug users afforded an opportunity to
evaluate the impact of this seizure.

Methods: The Vancouver Injection Drug User Study is a prospective cohort
study of injection drug users that began in 1996. The present study relied
primarily on data acquired from participants who were seen during the
30-day periods immediately before and after the seizure. We compared drug
use and behavioural characteristics, heroin and cocaine prices, and
participants' reports of whether law enforcement had affected their source
of drugs or the types of drugs available on the street, as well as
overdoses, in these 2 periods.

Results: The 138 participants seen before the seizure were similar to the
123 participants seen after the seizure with respect to age, sex, ethnic
background, education, HIV serostatus, neighbourhood residence, instability
of housing, employment status, use of methadone maintenance therapy and all
other measured potential confounders (all p 0.10). We found no difference
in the extent to which participants in the 2 groups reported daily use of
heroin, frequency of nonfatal overdoses, or whether law enforcement had
affected their source of drugs or the types of drugs available on the
street (all p 0.10). Although we detected no difference in the price of
cocaine, the median reported price of heroin went down after the seizure (p
= 0.034), which suggests that other shipments compensated for the seizure.
External evaluations of deaths from overdoses and heroin purity indicated
that the seizure had no impact, nor was any impact seen when the periods of
analysis were extended.

Interpretation: The massive heroin seizure appeared to have no measurable
public health benefit. Closer scrutiny of enforcement efforts is warranted
to ensure that resources are delivered to the most efficient and
cost-effective public health programs.

The primary response to the spread of HIV among injection drug users (IDUs)
has been to intensify law enforcement in an effort to limit the supply and
use of illicit drugs. Locally, the enforcement budget for Vancouver's
Downtown Eastside district has doubled since 1995, with no observed benefit
with regard to drug supply or public order (Vancouver District 2 total
budget figures for 1995­2001; Vancouver Police Department, Financial
Services, unpublished data), and reports of police misconduct in the
neighborhood have recently raised major concerns. At the national level, a
recent report from the Canadian auditor general estimated that of the $454
million spent in 1999/2000 to deal with illicit drugs in Canada, $426
million (93.8%) was devoted to reducing supply. Despite the expenditures on
supply reduction, high HIV incidence rates persist in many Canadian cities,
and overdoses of illicit drugs have been a leading cause of death.,

Few studies have attempted to evaluate the impact of the supply-reduction
strategy on community drug-use patterns. An Australian study found no
evidence that heroin seizures affected the price, purity or perceived
availability of heroin. Similarly, despite spending of over US$18 billion
annually on supply-reduction efforts in the United States, the most recent
heroin availability report from the US Office of National Drug Control
Policy stated that the price of heroin in that country decreased 3-fold
between 1988 and 2000, while purity has reached an all-time high.

On Sept. 2, 2000, Canadian law enforcement officials seized approximately
100 kg of uncut heroin soon after its arrival in the port of Vancouver, in
what was reportedly the nation's largest-ever seizure of the drug. To put
this seizure in perspective, the US Drug Enforcement Administration's
10-month Operation White Horse resulted in the seizure of 6.5 kg of heroin,
and the total amount of heroin seized by the US Customs Service along that
country's southwest border during the entire year 2000 was 113 kg.

In the wake of the Vancouver seizure, it was suggested that the removal of
this quantity of heroin from the market could substantially limit the
supply of the drug and could keep prices beyond the range of youth at high
risk for experimentation, and that it was responsible for a decline in the
city's overdose rate. We sought to determine if the seizure had a
measurable effect on the price of drugs, injection drug using behaviour,
the incidence of overdoses or the supply of heroin to Vancouver's IDUs.

Methods

Beginning in May 1996, IDUs were recruited into the Vancouver Injection
Drug User Study, a prospective cohort study that has been described in
detail previously., Over 1400 study subjects have been recruited through
self-referral and street outreach, and we have previously reported that the
cohort appears to be highly representative of IDUs in the Vancouver area.,

At baseline and semiannually thereafter, subjects provided blood samples
and completed an interviewer-administered questionnaire. The questionnaire
elicited demographic data including age, sex and place of residence, as
well as drug use, risk behaviour and attendance at drug treatment. In
addition, since the cohort's inception several general questions have been
added to evaluate the effect of law enforcement efforts on the supply of
drugs and patterns of drug use. Participants were also asked to report the
current street price per "point" (single shot) of injection heroin and
injection cocaine.

For the primary analysis in this study we assumed a priori that acute
street-level impacts would be measurable within a month starting the day
after the seizure., Therefore, pre-seizure and post-seizure participants
were defined as those seen for follow-up within 30 days before and 30 days
after Sept. 2, 2000, respectively. In addition, because of uncertainty
concerning the appropriateness of the 30-day period for observing any
impact of the seizure, we conducted several sensitivity analyses. First, we
compared participants seen during the 60 days before Sept. 2, 2000, with
those seen during the 60 days after this date. Second, we evaluated
participants seen in 6 successive 2-week periods after Sept. 2, 2000.

Statistical analyses were applied to compare pre- and post-seizure
participants. Categorical explanatory variables were analyzed with
Pearson's 2 test and Fisher's exact test, and continuous variables were
analyzed with the Wilcoxon rank-sum test. In addition, to adjust for
potential confounding due to differences between the IDUs seen before and
after the seizure, we conducted a logistic regression analysis in which the
dependent variable was the period (before v. after).

Results

In the 30 days before Sept. 2, 2000, 138 participants visited the study
site for follow-up; 123 participants visited for a follow-up visit in the
30 days after this date. The 2 groups were similar with respect to age,
sex, ethnic background, education, HIV serostatus, neighbourhood residence,
instability of housing, employment status, methadone use and all other
measured potential confounders (all p 0.10).

In univariate analyses of drug use and behavioural characteristics (), we
found no difference in the proportion of participants who reported that law
enforcement had affected their source of drugs (p = 0.55) or the type of
drugs available on the street (p = 0.73). Similarly, we found no
differences in overall drug-use pattern (p = 0.60), injection drug-use
pattern (p 0.13), current heroin use (p = 0.57), frequency of heroin
injection (p 0.52) or frequency of cocaine injection (p = 0.42). In
addition, we did not detect any difference in the proportion of
participants reporting a recent nonfatal overdose (within the previous 6
months) (p = 0.12). Although the seizure was not associated with a change
in the per-point price of cocaine (p = 0.36), we did detect a statistically
significant decrease in the per-point price of heroin, from a median of $20
before the seizure to a median of $16 after the seizure (p = 0.034). After
adjustment for all combinations of potential confounders, the decrease in
the price of heroin remained independently associated with the post-seizure
period in logistic regression analyses (p ( 0.05)

Furthermore, our findings were unaffected when we doubled the length of the
pre- and post-seizure periods and compared the 317 participants seen during
the 60 days before Sept. 2, 2000, with the 259 participants seen during the
60 days after this date. In this analysis, the median post-seizure
per-point price of heroin was higher than for the 30-day period, at $18
(interquartile range $14 to $20), but it was still lower than the 60-day
pre-seizure price, which remained unchanged at $20 (interquartile range $15
to $20).

The percentages of participants reporting current heroin use, methadone
maintenance therapy and recent nonfatal overdose during the period from 28
days (4 weeks) before Sept. 2, 2000, to 12 weeks after this date are shown
in . For all 3 variables, comparisons of periods were nonsignificant except
for the comparisons of period ­2 and period ­1 (the two 2-week periods
before the seizure) with period 2 (the second 2-week period after the
seizure) for nonfatal overdoses (p = 0.08 and p = 0.001 respectively); this
variable was moderately greater during period 2 than during periods ­2 and
­1. Not shown in the figure is the percentage of participants who reported
that law enforcement had affected the types of drugs available on the
street. On average, 22.2% of participants reported that law enforcement had
affected the types of drugs available during the 4 weeks before the
seizure, whereas 19.5% of participants reported that law enforcement had
affected the types of drugs available during the 12 weeks after the seizure
(p = 0.19).

Interpretation

The data presented here indicate that the record seizure of heroin in
autumn 2000 appeared to have no impact on injection use of heroin or on
perceived availability of heroin. Furthermore, we detected no difference in
the extent to which drug users reported that enforcement had affected their
drug source, the types of drugs available or their pattern of drug use.

Several factors may explain our observations. First, we must accept the
possibility that the results can be explained by chance or confounding
factors. Although we detected no evidence of a significant difference
between the 2 study groups, it is possible that unmeasured confounding
persisted. In addition, we recognize that the reduction in the price of
heroin that we observed was probably due to random fluctuation or
compensatory shipments and was not causally connected to the seizure. With
regard to the possibility that compensatory shipments explain our findings,
previous studies have found that heroin seizures tend to correlate with
times of high production and supply of drugs., We do not believe that
interview bias played a role because the interviews were not conducted to
assess the effect of the seizure but rather constituted the data instrument
for an ongoing HIV incidence study; thus the interviewers and participants
were in effect "blind" to this eventual use of the data. We should also
note that although 148 (56.7%) of those considered in the present analyses
were active heroin injectors, only 75 (28.7%) injected heroin daily.
Nevertheless, the results were unaffected when we restricted the analysis
to current heroin users (data not shown).

It could be argued that a 30-day period after the seizure was insufficient
to capture a reduction in supply due to the seizure. To address this
possibility, we conducted additional analyses and detected no difference
when we examined data for a full 12 weeks after the seizure. It could also
be argued that the heroin shipment was never intended for the local market.
Although the inability to determine with certainty the final destination of
the heroin is a limitation of the present study, the circumstances of the
seizure suggest that the heroin was destined for the Vancouver market.
Specifically, the seizure was the result of a 20-month investigation by the
Vancouver Royal Canadian Mounted Police Asian Organized Crime Unit, which
led to the arrest of several Vancouver men. During the investigation,
information was acquired that led officials to conclude that the heroin was
destined for the local market.,, Nevertheless, had the heroin been destined
for shipment away from the market created by the area's estimated 5000 to
10 000 injection drug users, this would suggest that the local market was
already saturated., Finally, it could be argued that the seizure led
suppliers to reduce the purity of the heroin they sold so as to maintain
the quantity of drug available. However, participants reported no
difference in their source of drugs or the type of drugs available, and we
found no decreases in overdoses or heroin use, nor any change in methadone
use when the 12-week post-seizure period was examined (). All of these
variables have previously been associated with fluctuations in the purity
of street-level heroin.,,

Externally compiled data appear to support our findings. Specifically,
there were 10 fatal overdose deaths in the month before the seizure,
whereas there was an average of 13.3 overdose deaths per month during the 3
months after the seizure (monthly illicit drug overdose statistics for
2000; BC Coroner Service, unpublished data). In addition, data from Health
Canada's Drug Analysis Services, a group that often tests the purity of
heroin samples provided by police, showed no decrease in the purity of
heroin samples tested during the 3-month periods before and after the
seizure (Health Canada, Drug Analysis Services, Burnaby, BC, unpublished data).

Analyses conducted by the United Nations Office for Drug Control and Crime
Prevention suggest that a maximum of 5% of the global illegal drug flow is
seized by law enforcement agencies. For this reason, despite the
expenditure of tens of billions of dollars annually on drug interdiction
efforts in North America, heroin purity has increased and prices have
markedly decreased since the late 1980s., In turn, high HIV incidence rates
have persisted, and overdose is among the leading cause of death in many
large Canadian and US cities.,,, In Baltimore, for example, overdose deaths
increased by more than 425% between 1990 and 1997.

In the present study we observed no beneficial public health effects of
Canada's largest-ever heroin seizure. In our view, the most plausible
explanation is that the seizure had no significant effect on the supply of
heroin in this locality. This conclusion is supported by a recent report by
the World Customs Organization, which found that even post-September 11
security measures have had a "negligible" impact on the influx of illicit
drugs into the US. Given the size of the seizure relative to other large
heroin seizures,, our findings raise serious questions about the potential
for Canada's present drug policies to adequately control the drug use
epidemic through supply-side interventions. It is critical to emphasize our
view that fault does not lie with the front-line law enforcement officers
who are involved in supply-side strategies at the operational level.
Rather, the responsibility lies with the politicians and policy-makers who
continue to direct the overwhelming majority of resources into failing
supply-reduction strategies, despite the wealth of scientific evidence
demonstrating their ineffectiveness.,,, Our findings support the strong
consensus that curbing the HIV and overdose epidemics will require a shift
in emphasis toward alternative strategies based on prevention, treatment
and harm reduction, even if this shift necessitates a diversion of
resources away from criminal justice interventions.,,,,,

Footnotes

This article has been peer reviewed.

Contributors: Evan Wood and Martin Schechter designed the study and
prepared the first draft of the manuscript. All authors played central
roles in the conception of the study and the interpretation of the data and
contributed to various drafts of the manuscript.

Acknowledgements: Evan Wood is supported by the Canadian Institutes for
Health Research and the BC Health Research Foundation. Martin Schechter
holds a tier I Canada Research Chair in HIV/AIDS and Urban Population
Health. The study was supported by the US National Institutes of Health
(grant RO1 DA11591).

We thank Bonnie Devlin, Caitlin Johnston, Robin Brooks, Suzy Coulter, Steve
Kain, Guillermo Fernandez, John Charette, Will Small, Peter Vann, Thomas
Kerr and Nancy Laliberte for their research and administrative assistance,
and all the participants in the VIDUS study.

Competing interests: None declared.

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