Jane A. Buxton

Smoking of crack cocaine as a risk factor for HIV infection among people who use injection drugs

Background: Little is known about the possible role that smoking crack cocaine has on the incidence of HIV infection. Given the increasing use of crack cocaine, we sought to examine whether use of this illicit drug has become a risk factor for HIV infection. Methods: We included data from people participating in the Vancouver Injection Drug Users Study who reported injecting illicit drugs at least once in the month before enrolment, lived in the greater Vancouver area, were HIV-negative at enrolment and completed at least 1 follow-up study visit. To determine whether the risk of HIV seroconversion among daily smokers of crack cocaine changed over time, we used Cox proportional hazards regression and divided the study into 3 periods: May 1, 1996–Nov. 30, 1999 (period 1), Dec. 1, 1999–Nov. 30, 2002 (period 2), and Dec. 1, 2002–Dec. 30, 2005 (period 3). Results: Overall, 1048 eligible injection drug users were included in our study. Of these, 137 acquired HIV infection during follow-up. The mean proportion of participants who reported daily smoking of crack cocaine increased from 11.6% in period 1 to 39.7% in period 3. After adjusting for potential confounders, we found that the risk of HIV seroconversion among participants who were daily smokers of crack cocaine increased over time (period 1: hazard ratio [HR] 1.03, 95% confidence interval [CI] 0.57–1.85; period 2: HR 1.68, 95% CI 1.01–2.80; and period 3: HR 2.74, 95% CI 1.06–7.11). Interpretation: Smoking of crack cocaine was found to be an independent risk factor for HIV seroconversion among people who were injection drug users. This finding points to the urgent need for evidence-based public health initiatives targeted at people who smoke crack cocaine.

Homelessness and unstable housing associated with an increased risk of HIV and STI transmission among street-involved youth.

The role that environmental factors play in driving HIV and STI transmission risk among street-involved youth has not been well examined. We examined factors associated with number of sex partners using quasi-Poisson regression and consistent condom use using logistic regression among participants enroled in the At Risk Youth Study (ARYS). Among 529 participants, 253 (47.8%) reported multiple partners while only 127 (24.0%) reported consistent condom use in the past 6 months. Homelessness was inversely associated with consistent condom use (adjusted odds ratio [aOR]=0.47, p=0.008), while unstable housing was positively associated with greater numbers of sex partners (adjusted incidence rate ratio [aIRR]=1.44, p=0.010). These findings indicate the need for interventions which modify environmental factors that drive risk among young street-involved populations.

Dose-response Effect of Incarceration Events on Nonadherence to HIV Antiretroviral Therapy Among Injection Drug Users

BACKGROUND Although some studies have identified impressive clinical gains for incarcerated HIV-seropositive injection drug users (IDUs) undergoing antiretroviral therapy (ART), the effect of incarceration on adherence to ART remains undetermined. METHODS We used data from a long-term community-recruited cohort of HIV-seropositive IDUs, including comprehensive ART dispensation records, in a setting where HIV care is free. We estimated the relationship between the cumulative burden of incarceration, measured longitudinally, and the odds of < 95% adherence to ART, with use of multivariate modeling. RESULTS From 1996 through 2008, 490 IDUs were recruited and contributed 2220 person-years of follow-up; 271 participants (55.3%) experienced an incarceration episode, with the number of incarcerations totaling 1156. In a multivariate model, incarceration had a strong dose-dependent effect on the likelihood of nonadherence to ART: 1-2 incarceration events (adjusted odds ratio [AOR], 1.49; 95% confidence interval [95% CI], 1.03-2.05), 3-5 events (AOR, 2.48; 95% CI, 1.62-3.65), and > 5 events (AOR, 3.11; 95% CI, 1.86-4.95). CONCLUSIONS Among HIV-seropositive IDUs receiving ART, an increasing burden of incarceration was associated with poorer adherence in a dose-dependent fashion. Our findings support improved adherence support for HIV-seropositive IDUs experiencing incarceration.

The relationship between minimum alcohol prices, outlet densities and alcohol‐attributable deaths in British Columbia, 2002–09

AIM To investigate relationships between periodic increases in minimum alcohol prices, changing densities of liquor stores and alcohol-attributable (AA) deaths in British Columbia, Canada. DESIGN Cross-section (16 geographic areas) versus time-series (32 annual quarters) panel analyses were conducted with AA deaths as dependent variables and price, outlet densities and socio-demographic characteristics as independent variables. SETTING AND PARTICIPANTS Populations of 16 Health Service Delivery Areas in British Columbia, Canada. MEASUREMENTS Age-sex-standardized rates of acute, chronic and wholly AA mortality; population densities of restaurants, bars, government and private liquor stores; minimum prices of alcohol in dollars per standard drink. FINDINGS A 10% increase in average minimum price for all alcoholic beverages was associated with a 31.72% [95% confidence interval (CI): ± 25.73%, P < 0.05] reduction in wholly AA deaths. Significantly negative lagged associations were also detected up to 12 months after minimum price increases for wholly but not for acute or chronic AA deaths. Significant reductions in chronic and total AA deaths were detected between 2 and 3 years after minimum price increases. Significant but inconsistent lagged associations were detected for acute AA deaths. A 10% increase in private liquor stores was associated with a 2.45% (95% CI: ± 2.39%, P < 0.05), 2.36% (95% CI: ± 1.57%, P < 0.05) and 1.99% (95% CI: ± 1.76%, P < 0.05) increase in acute, chronic and total AA mortality rates. CONCLUSION Increases in the minimum price of alcohol in British Columbia, Canada, between 2002 and 2009 were associated with immediate and delayed decreases in alcohol-attributable mortality. By contrast, increases in the density of private liquor stores were associated with increases in alcohol-attributable mortality.

Levamisole tainted cocaine causing severe neutropenia in Alberta and British Columbia

BackgroundFive cases of severe neutropenia (neutrophil counts < 0.5 per 109 cells/L) associated with exposure to cocaine and levamisole, an antihelimithic agent no longer available in Canada, were identified in Alberta in 2008. Alberta and British Columbia (BC) public health officials issued an advisory and urged health care professionals to report cases to public health. This paper presents the findings of the public health investigations.MethodsCases were identified prospectively through reporting by clinicians and a retrospective review of laboratory and medical examiners data from January 1, 2006 to March 31, 2009. Cases were categorized as confirmed, probable or suspect. Only the confirmed and probable cases are included in this paper.ResultsWe compare cases of severe neutropenia associated with tainted cocaine (NATC) identified in Alberta and BC between January 1, 2008 to March 31, 2009. Of the 42 NATC cases: 23(55%) were from Alberta; 19(45%) were from British Columbia; 57% of these cases reported crack cocaine use (93% of those who identified type of cocaine used); 7% reported using cocaine powder; and the main route of cocaine administration was from smoking (72%). Fifty percent of the NATC cases had multiple episodes of neutropenia associated with cocaine use. Cases typically presented with bacterial/fungal infections and fever. One Alberta NATC case produced anti-neutrophil antibodies, and four were positive for anti-neutrophil cytoplasmic antibody (ANCA). Analysis of two crack pipes and one drug sample obtained from NATC cases confirmed the presence of both cocaine and levamisole. A further 18 cases were identified through the retrospective review of laboratory and medical examiner data in AlbertaInterpretationOur findings support a link between neutropenia and levamisole tainted cocaine; particularly from smoking the crack form of cocaine. Some patients may be genetically predisposed to develop levamisole-related neutropenia. Awareness of the differential diagnosis will assist clinicians with case timely detection and appropriate management.

Minimum Alcohol Prices and Outlet Densities in British Columbia, Canada: Estimated Impacts on Alcohol-Attributable Hospital Admissions

OBJECTIVES We investigated whether periodic increases in minimum alcohol prices were associated with reduced alcohol-attributable hospital admissions in British Columbia. METHODS The longitudinal panel study (2002-2009) incorporated minimum alcohol prices, density of alcohol outlets, and age- and gender-standardized rates of acute, chronic, and 100% alcohol-attributable admissions. We applied mixed-method regression models to data from 89 geographic areas of British Columbia across 32 time periods, adjusting for spatial and temporal autocorrelation, moving average effects, season, and a range of economic and social variables. RESULTS A 10% increase in the average minimum price of all alcoholic beverages was associated with an 8.95% decrease in acute alcohol-attributable admissions and a 9.22% reduction in chronic alcohol-attributable admissions 2 years later. A Can

Homelessness as a Structural Barrier to Effective Antiretroviral Therapy Among HIV-Seropositive Illicit Drug Users in a Canadian Setting

0.10 increase in average minimum price would prevent 166 acute admissions in the 1st year and 275 chronic admissions 2 years later. We also estimated significant, though smaller, adverse impacts of increased private liquor store density on hospital admission rates for all types of alcohol-attributable admissions. CONCLUSIONS Significant health benefits were observed when minimum alcohol prices in British Columbia were increased. By contrast, adverse health outcomes were associated with an expansion of private liquor stores.

Large summertime influenza A outbreak among tourists in Alaska and the Yukon Territory

Despite the advent of effective antiretroviral therapy (ART), HIV-seropositive injection drug users (IDU) continue to suffer from elevated levels of morbidity and mortality. Evidence is needed to identify social- and structural-level barriers to effective ART. We investigated the impact of homelessness on plasma HIV RNA response among illicit drug users initiating ART in a setting with free and universal access to HIV care. We accessed data from a long-running prospective cohort of community-recruited IDU linked to comprehensive HIV clinical monitoring and ART dispensation records. Using Cox proportional hazards with recurrent events modeling, we estimated the independent effect of homelessness on time to plasma HIV viral load suppression. Between May 1996 and September 2009, 247 antiretroviral naïve individuals initiated ART and contributed 1755 person-years of follow-up. Among these individuals, the incidence density of plasma HIV RNA suppression less than 500 copies/mm(3) was 56.7 (95% confidence interval [CI]: 46.9-66.0) per 100 person-years. In unadjusted analyses, homelessness was strongly associated with lower rates suppression (hazard ratio = 0.56, 95% CI: 0.40-0.78, p = 0.001), however, after adjustment for adherence this association was no longer significant (adjusted hazard ratio = 0.79, 95% CI: 0.56-1.11, p = 0.177). Homelessness poses a significant structural barrier to effective HIV treatment. However, since this relationship appears to be mediated by lower levels of ART adherence, interventions to improve adherence among members of this vulnerable population are needed.

Social and structural factors associated with HIV disease progression among illicit drug users: a systematic review.

We investigated a large summertime outbreak of acute respiratory illness during May-September 1998 in Alaska and the Yukon Territory, Canada. Surveillance for acute respiratory illness (ARI), influenza-like illness (ILI), and pneumonia conducted at 31 hospital, clinic, and cruise ship infirmary sites identified 5361 cases of ARI (including 2864 cases of ILI [53%] and 171 cases of pneumonia [3.2%]) occurring primarily in tourists and tourism workers (from 18 and 37 countries, respectively). Influenza A viruses were isolated from 41 of 210 patients with ILI at 8 of 14 land sites and 8 of 17 cruise ship infirmaries. Twenty-two influenza isolates were antigenically characterized, and all were influenza A/Sydney/05/97-like (H3N2) viruses. No other predominant pathogens were identified. We estimated that >33,000 cases of ARI might have occurred during this protracted outbreak, which was attributed primarily to influenza A/Sydney/05/97-like (H3N2) viruses. Modern travel patterns may facilitate similar outbreaks, indicating the need for increased awareness about influenza by health care providers and travelers and the desirability of year-round influenza surveillance in some regions.

The burden and management of crystal meth use

Objective:To systematically review factors associated with HIV disease progression among illicit drug users, focusing on exposures exogenous to individuals that likely shape access and adherence to HIV treatment. Design:A systematic review of peer-reviewed English-language studies among HIV-seropositive illicit drug users with at least one of these endpoint of interest: a diagnosis of AIDS; death; changes/differences in CD4 cell counts; or changes/differences in plasma HIV-1 RNA levels. Methods:Articles were included if they reported factors associated with an outcome of interest among a group of illicit drug users. Studies were identified, screened and selected using systematic methods. Results:Of 2668 studies matching the search criteria, 58 (2%) met the inclusion criteria, all but one from North America or western Europe. Overall, 41 (71%) studies contained significant individual-level clinical characteristics or behaviors (e.g. illicit drug use) associated with disease progression. Fifteen studies (26%) identified significant social, physical, economic or policy-level exposures, including incarceration, housing status or lack of legal income. Conclusion:Although past studies demonstrate important environmental exposures that appear to shape access to care and subsequent disease progression, the limited literature to examine these factors demonstrates the need for future research to consider risk environment characteristics and the role they may play in shaping health outcomes from HIV infection among drug users through determining access and adherence to evidence-based care.