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Supervised injection facility use and all-cause mortality among people who inject drugs in Vancouver, Canada: A cohort study.

ABSTRACT: BACKGROUND:People who inject drugs (PWID) experience elevated rates of premature mortality. Although previous studies have demonstrated the role of supervised injection facilities (SIFs) in reducing various harms associated with injection drug use, including accidental overdose death, the possible impact of SIF use on all-cause mortality is unknown. Therefore, we examined the relationship between frequent SIF use and all-cause mortality among PWID in Vancouver, Canada. METHODS AND FINDINGS:Data were derived from 2 prospective cohort studies of PWID in Vancouver, Canada, between December 2006 and June 2017. Every 6 months, participants completed questionnaires that elicited information regarding sociodemographic characteristics, substance use patterns, social-structural exposures, and use of health services including SIFs. These data were confidentially linked to the provincial vital statistics database to ascertain mortality rates and causes of death. We used multivariable extended Cox regression analyses to estimate the independent association between frequent (i.e., at least weekly) SIF use and all-cause mortality. Of 811 participants, 278 (34.3%) were women, and the median age was 39 years (IQR 33-46) at baseline. In total, 432 (53.3%) participants reported frequent SIF use at baseline, and 379 (46.7%) did not. At baseline, frequent SIF users were on average younger than nonfrequent users, and a higher proportion of frequent SIF users than nonfrequent users were unstably housed, resided in the Downtown Eastside neighbourhood, injected in public, had a recent non-fatal overdose, used prescription opioids at least daily, injected heroin at least daily, injected cocaine at least daily, and injected crystal methamphetamine at least daily. A lower proportion of frequent SIF users than nonfrequent users were HIV positive and enrolled in addiction treatment at baseline. The median duration of follow-up among study participants was 72 months (IQR 24-123). In total, 112 participants (13.8%) died during the study period, yielding a crude mortality rate of 22.7 (95% CI 18.7-27.4) deaths per 1,000 person-years. The median years of potential life lost per death was 34 (IQR 27-42) years. In a time-updated multivariable model, frequent SIF use was inversely associated with risk of all-cause mortality after adjusting for potential confounders, including age, sex, HIV seropositivity, unstable housing, at least daily cocaine injection, public injection, incarceration, enrolment in addiction treatment, and calendar year of interview (adjusted hazard ratio 0.46, 95% CI 0.26-0.80, p = 0.006). The main study limitations are the limited generalizability of findings due to non-random sampling, the potential for reporting biases due to reliance on some self-reported information, and the possibility that residual confounding influenced findings. CONCLUSIONS:We observed a high burden of premature mortality among a community-recruited cohort of PWID. Frequent SIF use was associated with a lower risk of death, independent of relevant confounders. These findings support efforts to enhance access to SIFs as a strategy to reduce mortality among PWID. Further analyses of individual-level data are needed to determine estimates of, and potential causal pathways underlying, associations between SIF use and specific causes of death.

SUBMITTER: Kennedy MC

PROVIDER: S-EPMC6879115 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature

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Supervised injection facility use and all-cause mortality among people who inject drugs in Vancouver, Canada: A cohort study.

Kennedy Mary Clare MC Hayashi Kanna K Milloy M-J MJ Wood Evan E Kerr Thomas T

PLoS medicine 20191126 11

<h4>Background</h4>People who inject drugs (PWID) experience elevated rates of premature mortality. Although previous studies have demonstrated the role of supervised injection facilities (SIFs) in reducing various harms associated with injection drug use, including accidental overdose death, the possible impact of SIF use on all-cause mortality is unknown. Therefore, we examined the relationship between frequent SIF use and all-cause mortality among PWID in Vancouver, Canada.<h4>Methods and fin ...[more]

PMID: 31770391

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Project description:BackgroundIndividuals who initiate injection drug use often receive assistance from an injection-knowledgeable peer. Persons who assist peers in injection initiation events often inject frequently, which heightens overdose risk. As such, overdose and injection initiation events may be correlated. To explore a potential relationship, we assessed temporal associations between experiencing a non-fatal overdose and assisting others in initiating injection drug use among persons who inject drugs in two North American cities - Vancouver, Canada and Tijuana, Mexico.MethodsFrom 2014 to 2018, this retrospective cohort study included people who inject drugs from Vancouver (n=1332) and Tijuana (n=666) who completed a baseline and six-month follow-up interview. Within each site, we assessed bidirectional temporal associations using two separate multivariable logistic regression models: for model 1, recent provision of injection initiation assistance (at six months) was the outcome and recent overdose (at baseline) was the exposure; for model 2, recent overdose (at six months) was the outcome and recent provision of injection initiation assistance (at baseline) was the exposure. Both models adjusted for potential confounders.ResultsVancouver-based participants reporting overdose at baseline had 163% greater odds of reporting provision of injection initiation assistance at follow-up (adjusted Odds Ratio [aOR] 2.63; 95% Confidence Interval [CI] 1.41-4.90); while participants reporting provision of injection initiation assistance at baseline had 89% greater odds of reporting a non-fatal overdose at follow-up (aOR 1.89; 95% CI 1.00-3.57). Among Tijuana-based participants, we did not observe a statistically significant association in either direction.ConclusionFindings in Vancouver suggest that injection initiation assistance and overdose are bidirectionally-associated phenomena. The present findings highlight the need for interventions that ensure that persons who provide injection initiation assistance are given overdose prevention support, both for themselves and for those they assist to initiate injection drug use. While our Tijuana-based results did not suggest a bidirectional relationship, preventative approaches should nonetheless be undertaken.

Project description:BackgroundBetween June and November 2017, four supervised consumption sites (SCS) began operating in Montreal, Quebec. Earlier studies on SCS focused on examining their effects on blood-borne viral infections and overdose mortality. Our objective was to examine the effect of Montreal's SCS on the incidence, health service use and outcomes of injection-related infections (IRI) in people who inject drugs.MethodsWe used Quebec's provincial administrative health data to identify people who inject drugs in Montreal and calculated the incidence of IRI in this population between December 2014 and December 2019. We conducted a retrospective, population-based interrupted time series to estimate the effect of Montreal's four SCS on the monthly incidence rates of IRI-related hospitalizations, emergency department (ED) visits, physician visits, and mortality. We also examined the effects of SCS on average length of IRI-related hospitalizations and incidence of hospitalizations involving surgery.ResultsThe average age of Montreal's people who inject drugs was 41.84 years, and 66.41% were male. After the implementation of SCS, there was a positive level change in the incidence of hospitalizations (0.97; 95% confidence interval [CI]: 0.26, 1.68) for IRI. There was also a significant post-intervention decline in hospitalization trends (-0.05; 95% CI: -0.08, -0.02), with modest trend changes in ED visits (-0.02; 95% CI: -0.05, 0.02). However, post-intervention changes in level (0.72; 95% CI: -3.85, 5.29) and trend (0.06; 95% CI: -0.23, 0.34) for physician visits remained limited. SCS had no effect on the average length of hospitalizations, but there was a decreasing post-intervention trend in hospitalizations involving surgery (-0.03; 95% CI: -0.06, 0.00).ConclusionFollowing the opening of the SCS, there was a moderate decline in the rate of hospitalizations to treat IRI, but the impact of the sites on the rate of physician visits remained limited. These findings suggest that SCS may mitigate the incidence of more serious and complicated IRI over time.

Project description:BackgroundThe cost-effectiveness of Canada's only supervised injection facility has not been rigorously evaluated. We estimated the impact of the facility on survival, rates of HIV and hepatitis C virus infection, referral to methadone maintenance treatment and associated costs.MethodsWe simulated the population of Vancouver, British Columbia, including injection drug users and persons infected with HIV and hepatitis C virus. The model used a time horizon of 10 years and the perspective of the health care system. We compared the situation of the supervised injection facility with one that had no facility but that had other interventions, such as needle-exchange programs. The effects considered were decreased needle sharing, increased use of safe injection practices and increased referral to methadone maintenance treatment. Outcomes included life-years gained, costs, and incremental cost-effectiveness ratios discounted at 5% per year.ResultsFocusing on the base assumption of decreased needle sharing as the only effect of the supervised injection facility, we found that the facility was associated with an incremental net savings of almost $14 million and 920 life-years gained over 10 years. When we also considered the health effect of increased use of safe injection practices, the incremental net savings increased to more than $20 million and the number of life-years gained to 1070. Further increases were estimated when we considered all 3 health benefits: the incremental net savings was more than $18 million and the number of life-years gained 1175. Results were sensitive to assumptions related to injection frequency, the risk of HIV transmission through needle sharing, the frequency of safe injection practices among users of the facility, the costs of HIV-related care and of operating the facility, and the proportion of users who inject in the facility.InterpretationVancouver's supervised injection site is associated with improved health and cost savings, even with conservative estimates of efficacy.

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Supervised injection facility use and all-cause mortality among people who inject drugs in Vancouver, Canada: A cohort study.

Publications

Supervised injection facility use and all-cause mortality among people who inject drugs in Vancouver, Canada: A cohort study.

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