Predictors of mortality in the Amsterdam cohort of human immunodeficiency virus (HIV)-positive and HIV-negative drug users

Human Immunodeficiency Virus-Induced Interferon-Stimulated Gene Expression Is Associated With Monocyte Activation and Predicts Viral Load

Background

Chronic immune activation is one of the hallmarks of human immunodeficiency virus (HIV) pathogenesis. Persistent upregulation of interferons (IFNs) and interferon-stimulated genes (ISGs) has previously been associated with chronic immune activation and HIV progression. Here a longitudinal analysis of the IFN and ISG response during HIV infection was performed to gain insights into the ongoing immune activation during HIV infection.

Methods

IFN and ISG levels were determined using quantitative polymerase chain reaction in peripheral blood mononuclear cells of people with HIV at pre-seroconversion, during acute and chronic HIV infection, and during suppressive antiretroviral therapy (ART).

Results

HIV infection induced the expression of a set of 4 ISGs-RSAD2, ISG15, IFI44L, and IFI27-which remained upregulated during chronic infection. This set of ISGs showed no clear correlations with T-cell activation as determined by co-expression of CD38 and HLA-DR. However, a strong correlation with monocyte activation marker soluble CD163 in serum was found. Furthermore, the expression of this ISG cluster was predictive of viral load before ART initiation and, on ART, expression levels normalized to pre-seroconversion levels.

Conclusions

The results presented here suggests that ISG expression is linked to monocyte activation, possibly driven by viral replication.

First-line opioid agonist treatment as prevention against assisting others in initiating injection drug use: A longitudinal cohort study of people who inject drugs in Vancouver, Canada

Background

Among people who inject drugs, frequent injecting and experiencing withdrawal are associated with facilitating others' first injections. As these factors may reflect an underlying substance use disorder, we investigated whether first-line oral opioid agonist treatment (OAT; methadone or buprenorphine/naloxone) reduces the likelihood that people who inject drugs help others initiate injecting.

Methods

We used questionnaire data from semi-annual visits between December 2014-May 2018 on 334 people who inject drugs with frequent non-medical opioid use in Vancouver, Canada. We estimated the effect of current first-line OAT on subsequent injection initiation assistance provision (i.e., helped someone initiate injecting in the following six months) using inverse-probability-weighted estimation of repeated measures marginal structural models to reduce confounding and informative censoring by time-fixed and time-varying covariates.

Results

By follow-up visit, 54-64% of participants reported current first-line OAT whereas 3.4-6.9% provided subsequent injection initiation assistance. Per the primary weighted estimate (n = 1114 person-visits), participants currently on first-line OAT (versus no OAT) were 50% less likely, on average, to subsequently help someone initiate injecting (relative risk [RR]=0.50, 95% CI=0.23-1.11). First-line OAT was associated with reduced risk of subsequent injection initiation assistance provision in participants who, at baseline, injected opioids less than daily (RR=0.15, 95% CI=0.05-0.44) but not in those who injected opioids daily (RR=0.86, 95% CI=0.35-2.11).

Conclusions

First-line OAT seemingly reduces the short-term likelihood that people who inject drugs facilitate first injections. However, the extent of this potential effect remains uncertain due to imprecise estimation and observed heterogeneity by baseline opioid injecting frequency.

All-cause and cause-specific mortality among people with regular or problematic cocaine use: a systematic review and meta-analysis

AIMS

To estimate pooled all-cause and cause-specific mortality risk for people with regular or problematic cocaine use.

METHODS

Systematic review and meta-analysis of prospective or retrospective cohort studies or clinical trials (n ≥30) of people with regular or problematic cocaine use with data on all-cause or cause-specific mortality. Of 2808 papers, 28 were eligible and reported on 21 cohorts, with a total 170 019 individuals. Cohorts identified based on acute care for drug poisoning or other severe health presentation were excluded. Title/abstract screening was conducted by one reviewer; a second reviewer independently checked 10% of excluded studies. Two reviewers conducted full-text screening. Data were extracted by one reviewer and checked by a second. A customized review-specific study reporting quality/risk of bias tool was used. Data on crude mortality rates (CMR) and standardized mortality ratios were extracted for both all-cause and cause-specific mortality. Standardized mortality ratios were imputed where not provided by the author using extracted data and information from the Global Burden of Disease Study 2017. Data were pooled using a random-effects model.

RESULTS

The pooled all-cause crude mortality rate was 1.24 per 100 person-years [95% confidence interval (CI) = 0.86, 1.78; n = 16 cohorts], but with considerable heterogeneity (I²  = 98.8%). The pooled all-cause standardized mortality ratio (SMR) was 6.13 (95% CI = 4.15, 9.05; n = 16 cohorts). Suicide (SMR = 6.26, 95% CI = 2.84, 13.80), accidental injury (SMR = 6.36, 95% CI = 4.18, 9.68), homicide (SMR = 9.38, 95% CI 3.45-25.48) and AIDS-related mortality (SMR = 23.12, 95% CI = 11.30, 47.31) were all elevated compared with age and sex peers in the general population.

CONCLUSIONS

There are elevated rates of mortality among people with regular or problematic cocaine use for traumatic deaths and deaths attributable to infectious disease.

Lessons learned from the Amsterdam Cohort Studies among people who use drugs: a historical perspective

The Netherlands is well known for its early adoption of harm reduction (HR) programs at the height of its heroin crisis in the 1970s/1980s, including the implementation of the first needle and syringe program worldwide. In this manuscript, we describe how the Amsterdam Cohort Studies (ACS) among people who use drugs (PWUD) was conceived within the context of the Dutch HR approach, including the challenges scientists faced while establishing this cohort. This required striking a balance between public health and individual benefit, solving research dilemmas in the face of uncertainty, developing controversial innovative and cutting-edge interventions, which changed the prevention landscape for PWUD, and using longitudinal cohort data to provide unique insights. Studies from the ACS covering follow-up between 1985 and 2016 revealed that participation in both opioid agonist therapy and needle and syringe programs led to a major decrease in the risk of HIV and hepatitis B and C infection acquisition. ACS data have shown that the observed decrease in incidence also likely included shifts in drug markets and drug culture over time, selective mortality among those with the highest levels of risk behaviour, demographic changes of the PWUD population, and progression of the HIV and HCV epidemics. Moreover, HR programs in the Netherlands provided services beyond care for drug use, such as social support and welfare services, likely contributing to its success in curbing the HIV and viral hepatitis epidemics, increasing access and retention to HIV and HCV care and ultimately decreases in overdose mortality over time. Given the low coverage of HR programs in certain regions, it is unsurprising that continued HIV and HCV outbreaks occur and that transmission is ongoing in many countries worldwide. If we aim to reach the World Health Organization viral hepatitis and HIV elimination targets in 2030, as well as to improve the life of PWUD beyond infection risk, comprehensive HR programs need to be integrated as a part of prevention services, as in the Netherlands. We should use the evidence generated by longstanding cohorts, including the ACS, as a basis for which implementation and improved coverage of integrated HR services can be achieved for PWUD worldwide.

Drugs, discipline and death: Causes and predictors of mortality among people who inject drugs in Tijuana, 2011-2018

BACKGROUND

People who inject drugs (PWID) experience multiple risk factors for mortality; yet, we know little about causes of death among PWID in Tijuana, Mexico, an area with high levels of injecting and changes in policy/law enforcement responses to substance use. This study examines rates, causes, and predictors of mortality among Tijuana PWID.

METHODS

Data come from a community-based cohort of PWID aged ≥18 who injected drugs in the past month. Mortality was confirmed by death certificate over 78 months during 2011-2018. Predictors of mortality were identified using time-updated Cox regression, controlling for age.

RESULTS

Among 734 participants, there were 130 deaths (54 confirmed, 76 unconfirmed), with an incidence rate of 17.74 deaths per 1000 person-years for confirmed deaths (95% Confidence Interval (CI)=13.01, 22.48) and 39.52 for unconfirmed deaths (CI=32.72, 46.31). Confirmed deaths resulted from homicide/trauma (26%), overdose (26%), septic shock (18%) and HIV-related causes (9%). In multivariable analysis of confirmed deaths, baseline HIV seropositivity (adjusted Hazard Ratio [aHR]=6.77, CI=1.98, 23.17), incident HIV infection (aHR=3.19, CI=1.02, 9.96), and number of times being beaten by police in the past 6 months at baseline (aHR=1.08 per time, CI=1.04, 1.12) were predictive of death; whereas, injection cessation for 6+ months during time at risk (aHR=0.25, CI=0.33, 0.79) was protective.

CONCLUSION

In addition to overdose and HIV prevention efforts, attention to structural conditions that potentiate mortality is needed, including improved access to medication-assisted treatment to support injection cessation and a shift from police as a source of harm to harm reduction.

Mortality among people with regular or problematic use of amphetamines: a systematic review and meta-analysis

BACKGROUND AND AIMS

Amphetamines are the second most commonly used class of illicit drugs. We aimed to produce pooled estimates of mortality risks among people with regular or dependent use of amphetamines, with a focus upon all-cause mortality as well as specific causes of death.

DESIGN

Systematic review and meta-analysis of cohorts of people with problematic use or dependence on amphetamines with data on all-cause or cause-specific mortality.

SETTING AND PARTICIPANTS

Of 4240 papers, 30 were eligible, reporting on 25 cohorts that measured all-cause mortality, drug poisoning, suicide, accidental injuries, homicide and cardiovascular mortality. Cohorts (n = 35-74 139) were in North America, several Nordic countries and Asia Pacific.

MEASUREMENT

Titles/abstracts were independently screened by one reviewer and excluded those reviewed by a second reviewer. Full-text screening was by two reviewers with discrepancies resolved via a third reviewer. We extracted data on crude mortality rates (CMR) per 100 person-years (py), standardized mortality ratios (SMRs). We imputed SMRs where possible if not reported by study authors. We also calculated mortality relative risks. Data were pooled using random-effects models; potential reasons for heterogeneity were explored using subgroup analyses and meta-regressions.

FINDINGS

Twenty-three cohorts contributed data for the pooled all-cause CMR: 1.14 per 100 py [95% confidence interval (CI) = 0.92-1.42]. Pooled cause-specific mortality rates were: drug poisoning, 0.14 per 100 py (95% CI = 0.06-0.34); cardiovascular disease, 0.13 per 100 py (95% CI = 0.06-0.29); suicide, 0.20 per 100 py (95% CI = 0.07-0.55); accidental injury, 0.20 per 100 py (95% CI = 0.08-0.47) and homicide, 0.03 per 100 py (95% CI = 0.02-0.06). There was substantial heterogeneity for all pooled CMR estimates except homicide. The pooled all-cause SMR was 6.83 (95% CI = 5.27-8.84). Pooled cause-specific SMRS were: poisoning, 24.70 (95% CI = 16.67, 36.58); homicide, 11.90 (95% CI = 7.82-18.12); suicide, 12.20 (95% CI = 4.89-30.47); cardiovascular disease, 5.12 (95% CI = 3.74-7.00) and accidental injury, 5.12 (95% CI = 2.88-9.08).

CONCLUSIONS

People with regular or dependent amphetamine use are at elevated risk of a range of causes of mortality compared with people without regular or dependent amphetamine use.

Patterns of substance use and mortality risk in a cohort of 'hard-to-reach' polysubstance users

AIMS

To examine the mortality risk in a cohort of 'hard-to-reach' polysubstance users and its putative associations with substance use. Specifically, we estimated all-cause mortality risk as a function of individual substance use indicators, and then as a function of their complex, 'real-life' patterns as identified through latent class analysis (LCA).

DESIGN

Prospective cohort study among street- and low-threshold service-recruited polysubstance users included between September and November 2013 and followed through the National Cause of Death Registry until 31 October 2015.

SETTING

Seven Norwegian cities.

PARTICIPANTS

A total of 884 users of illegal opioids and/or stimulants. Of these, 357 were in opioid substitution treatment (OST) at the time of inclusion. Forty-four participants died during follow-up.

MEASUREMENTS

Primary outcome: all-cause mortality risk. Unadjusted and adjusted Cox proportional hazard (PH) regression models (covariates: male, age, homelessness/shelter use, overdose experience, OST status, years of injecting, individual substance use indicators, city, use patterns). LCA models estimated separately for those in and those not in OST due to measurement invariance.

FINDINGS

The crude mortality rate was 2.52 per 100 person-years. Standardized mortality ratio was 26.11 [95% confidence interval (CI) = 10.06-54.87] for women and 10.71 (95% CI = 6.39-16.81) for men. No single drug use indicator, such as 'heroin injection' or 'number of drugs used', was associated with the mortality risk. However, meaningful use patterns were identified; three OST and non-OST patterns each. The non-OST patterns 'polysubstance injectors' [hazard ratio (HR) = 3.45, 95% CI = 0.98-12.14] and 'low frequent injectors' (HR = 3.17, CI = 1.05-9.56) were associated significantly with the mortality risk even when adjusted for other known risk factors.

CONCLUSIONS

In a Norwegian prospective cohort study, 'hard-to-reach' polysubstance users had a more than 10 times higher mortality risk than the general population. Mortality risk was not a function of any single drug use indicator, but two distinct combinations of substances, frequencies and routes of administration were associated with the mortality risk.

Effect of ageing and time since first heroin and cocaine use on mortality from external and natural causes in a Spanish cohort of drug users

BACKGROUND

We aimed to assess the effect of ageing and time since first heroin/cocaine use on cause-specific mortality risk and age disparities in excess mortality among heroin (HUs) and cocaine users (CUs) in Spain.

METHODS

A cohort of 15,305 HUs and 11,905 CUs aged 15-49 starting drug treatment during 1997-2007 in Madrid and Barcelona was followed until December 2008. Effects of ageing and time since first heroin/cocaine use were estimated using a competing risk Cox model and the relative and absolute excess mortality compared to the general population through directly age-sex standardized rate ratios (SRRs) and differences (SRDs), respectively.

RESULTS

Mortality risk from natural causes increased with time since first heroin use, whereas that from overdose declined after having peaked in the first quinquennium. Significant effects of time since first cocaine use were not identified, although fatal overdose risk seemed higher in CUs after five years. Mortality risk from natural causes (HUs and CUs), injuries (HUs), and overdoses (CUs) increased with age, the latter without reaching statistical significance. Crude mortality rates from overdoses and injuries remained very high at age 40-59 among both HUs (595 and 217 deaths/100,000 person-years, respectively) and CUs (191 and 88 deaths/100,000 person-years). SRDs from all and natural causes were much higher at age 40-59 than 15-29 in both HUs (2134 vs. 834 deaths/100,000 person-years) and CUs (927 vs. 221 deaths/100,000 person-years), while the opposite occurred with SRRs.

CONCLUSION

The high mortality risk among HUs and CUs at all ages from both external and natural causes, and increased SRDs with ageing, suggest that high-level healthcare and harm reduction services should be established early and maintained throughout the lifetime of these populations.

Mortality Trends among Cocaine Users Treated between 1989 and 2013 in Northern Italy: Results of a Longitudinal Study

A total of 852 participants attending 11 centers for addiction treatment in north Italy following problems due to cocaine abuse between 1989 and 2013 were recruited. Two typologies were created: cocaine users (never heroin) (CU) and heroin and cocaine users (HCU). During the 38-year follow-up period, 4.8% of the whole cohort died. Over the whole period, tumors were the main causes of death; starting in 2010, suicide deaths became the first cause of death. Among CUs, most deaths were due to road accidents and suicide; among HCUs, most of the deaths were from opiate overdose and from cardio-circulatory system diseases. The excess mortality observed for all causes in either sex was 6.24; higher in females (15.03) as compared in males (6.23), higher in HCUs (9.06) as compared in CUs (5.21). The directly age-sex standardized mortality rates were 5.31 per 100, higher for females, declining after 2009 for all patients and after 2004 for HCUs. Multivariate analysis confirms the decreasing trend in the risk of death and shows a higher mortality risk for participants in the under-25 age group. Among cocaine users, special attention should be paid to the prevention of suicide deaths.

No association between HIV status and risk of non-fatal overdose among people who inject drugs in Vancouver, Canada

BACKGROUND

The evidence to date on whether HIV infection increases the risk of accidental drug overdose among people who inject drugs (PWID) is equivocal. Thus, we sought to estimate the effect of HIV infection on risk of non-fatal overdose among two parallel cohorts of HIV-positive and -negative PWID.

METHODS

Data were collected from a prospective cohort of PWID in Vancouver, Canada between 2006 and 2013. During biannual follow-up assessments, non-fatal overdose within the previous 6months was assessed. Bivariable and multivariable generalized mixed-effects regression models were used to determine the unadjusted and adjusted associations between HIV status, plasma HIV-1 RNA viral load, and likelihood of non-fatal overdose.

RESULTS

A total of 1760 eligible participants (67% male, median age=42, and 42% HIV-positive at baseline) were included. Among 15,070 unique observations, 649 (4.3%) included a report of a non-fatal overdose within the previous 6months (4.4% among seropositive and 4.3% among seronegative individuals). We did not observe a difference in the likelihood of overdose by HIV serostatus in crude (odds ratio [OR]: 1.05, p=0.853) analyses or analyses adjusted for known overdose risk factors (adjusted OR [AOR]: 1.19, p=0.474). In a secondary analysis, among HIV-positive PWID, we did not observe an association between having a detectable viral load and overdose (AOR: 1.03, p=0.862).

CONCLUSIONS

Despite the evidence that HIV infection is a risk factor for fatal overdose, we found no evidence for a relationship between HIV disease and non-fatal overdose. However, overdose remains high among PWID, indicating the need for ongoing policy addressing this problem, and research into understanding modifiable risk factors that predict non-fatal overdose.

Understanding the effects of different HIV transmission models in individual-based microsimulation of HIV epidemic dynamics in people who inject drugs

We investigated how different models of HIV transmission, and assumptions regarding the distribution of unprotected sex and syringe-sharing events ('risk acts'), affect quantitative understanding of HIV transmission process in people who inject drugs (PWID). The individual-based model simulated HIV transmission in a dynamic sexual and injecting network representing New York City. We constructed four HIV transmission models: model 1, constant probabilities; model 2, random number of sexual and parenteral acts; model 3, viral load individual assigned; and model 4, two groups of partnerships (low and high risk). Overall, models with less heterogeneity were more sensitive to changes in numbers risk acts, producing HIV incidence up to four times higher than that empirically observed. Although all models overestimated HIV incidence, micro-simulations with greater heterogeneity in the HIV transmission modelling process produced more robust results and better reproduced empirical epidemic dynamics.

Examining non-AIDS mortality among people who inject drugs

Objective:

To systematically review and analyse data from cohorts of people who inject drugs (PWID) to improve existing estimates of non-AIDS mortality used to calculate mortality among PWID in the Spectrum Estimates and Projection Package.

Design:

Systematic review and meta-analysis.

Methods:

We conducted an update of an earlier systematic review of mortality among PWID, searching specifically for studies providing data on non-AIDS-related deaths. Random-effects meta-analyses were performed to derive pooled estimates of non-AIDS crude mortality rates across cohorts disaggregated by sex, HIV status and periods in and out of opioid substitution therapy (OST). Within each cohort, ratios of non-AIDS CMRs were calculated and then pooled across studies for the following paired sub-groups: HIV-negative versus HIV-positive PWID; male versus female PWID; periods in OST versus out of OST. For each analysis, pooled estimates by country income group and by geographic region were also calculated.

Results:

Thirty-seven eligible studies from high-income countries and five from low and middle-income countries were found. Non-AIDS mortality was significantly higher in low and middle-income countries [2.74 per 100 person-years; 95% confidence interval (CI) 1.76–3.72] than in high-income countries (1.56 per 100 person-years; 95% CI 1.38–1.74). Non-AIDS CMRs were 1.34 times greater among men than women (95% CI 1.14–1.57; N = 19 studies); 1.50 times greater among HIV-positive than HIV-negative PWID (95% CI 1.15, 1.96; N = 16 studies); and more than three times greater during periods out of OST than for periods on OST (N = 7 studies).

Conclusions:

A comprehensive response to injecting drug must include efforts to reduce the high levels of non-AIDS mortality among PWID. Due to limitations of currently available data, including substantial heterogeneity between studies, estimates of non-AIDS mortality specific to geographic regions, country income level, or the availability of OST should be interpreted with caution.

Mortality, causes of death and risk factors for death among primary amphetamine users in the Swedish criminal justice system

This study examined mortality and predictors of death in 1,396 primary amphetamine users (85% males) who were interviewed with the Addiction Severity Index in the Swedish criminal justice system during 2000-2006 and followed through 2008. Forty-nine clients deceased (standardized mortality ratio 4.1 [3.0-5.4]), at least 84% of deaths were violent or drug-related (12% suicides), and Cox regression analysis indicated that death was associated with frequent use of sedatives and less frequent use of amphetamine. No female deaths were observed; death and male gender were associated in binary analysis. Implications for diagnostics and treatment are discussed.

Mortality among people who inject drugs: a systematic review and meta-analysis

OBJECTIVE

To systematically review cohort studies of mortality among people who inject drugs, examine mortality rates and causes of death in this group, and identify participant- and study-level variables associated with a higher risk of death.

METHODS

Tailored search strings were used to search EMBASE, Medline and PsycINFO. The grey literature was identified through online grey literature databases. Experts were consulted to obtain additional studies and data. Random effects meta-analyses were performed to estimate pooled crude mortality rates (CMRs) and standardized mortality ratios (SMRs).

FINDINGS

Sixty-seven cohorts of people who inject drugs were identified, 14 of them from low- and middle-income countries. The pooled CMR was 2.35 deaths per 100 person-years (95% confidence interval, CI: 2.12-2.58). SMRs were reported for 32 cohorts; the pooled SMR was 14.68 (95% CI: 13.01-16.35). Comparison of CMRs and the calculation of CMR ratios revealed mortality to be higher in low- and middle-income country cohorts, males and people who injected drugs that were positive for human immunodeficiency virus (HIV). It was also higher during off-treatment periods. Drug overdose and acquired immunodeficiency syndrome (AIDS) were the primary causes of death across cohorts.

CONCLUSION

Compared with the general population, people who inject drugs have an elevated risk of death, although mortality rates vary across different settings. Any comprehensive approach to improving health outcomes in this group must include efforts to reduce HIV infection as well as other causes of death, particularly drug overdose.

Injecting drug use is associated with a more rapid CD4 cell decline among treatment naïve HIV-positive patients in Indonesia

Background

It remains unclear whether the natural course of human immunodeficiency virus (HIV) differs in subjects infected through injecting drug use (IDU) and no data have been published from low- or middle-income countries. We addressed this question in an urban cohort in Indonesia, which is experiencing a rapidly growing HIV epidemic strongly driven by IDU.

Methods

All antiretroviral treatment (ART) naïve HIV-positive patients who had at least two subsequent CD4 cell counts available before starting ART were included in this study. We examined the association between IDU and CD4 cell decline using a linear mixed model, with adjustment for possible confounders such as HIV viral load and hepatitis C antibodies.

Results

Among 284 HIV-positive ART naïve patients, the majority were male (56%) with a history of IDU (79% among men). People with a history of IDU had a statistically significant faster decline in CD4 cells (p<0.001). Based on our data, patients with a history of IDU would have an average 33% decline in CD4 cells after one year without ART, compared with a 22% decline among non-users. At two years, the decline would average 66 and 40%, respectively. No other factor was significantly associated with CD4 cell decline.

Conclusions

We show that a history of IDU is associated with a more rapid CD4 cell natural decline among HIV-positive individuals in Indonesia. These findings have implications for monitoring ART naïve patients with a history of IDU and for starting ART in this group.

Crystal methamphetamine and initiation of injection drug use among street-involved youth in a Canadian setting

BACKGROUND

Although injection drug use is known to result in a range of health-related harms, including transmission of HIV and fatal overdose, little is known about the possible role of synthetic drugs in injection initiation. We sought to determine the effect of crystal methamphetamine use on risk of injection initiation among street-involved youth in a Canadian setting.

METHODS

We used Cox regression analyses to identify predictors of injection initiation among injection-naive street-involved youth enrolled in the At-Risk Youth Study, a prospective cohort study of street-involved youth in Vancouver, British Columbia. Data on circumstances of first injection were also obtained.

RESULTS

Between October 2005 and November 2010, a total of 395 drug injection-naive, street-involved youth provided 1434 observations, with 64 (16.2%) participants initiating injection drug use during the follow-up period, for a cumulative incidence of 21.7 (95% confidence interval [CI] 1.7-41.7) per 100 person-years. In multivariable analysis, recent noninjection use of crystal methamphetamine was positively associated with subsequent injection initiation (adjusted hazard ratio 1.93, 95% CI 1.31-2.85). The drug of first injection was most commonly reported as crystal methamphetamine (14/31 [45%]).

INTERPRETATION

Noninjection use of crystal methamphetamine predicted subsequent injection initiation, and crystal methamphetamine was the most commonly used drug at the time of first injection. Evidence-based strategies to prevent transition to injection drug use among crystal methamphetamine users are urgently needed.

A complex systems approach to evaluate HIV prevention in metropolitan areas: preliminary implications for combination intervention strategies

BACKGROUND

HIV transmission among injecting and non-injecting drug users (IDU, NIDU) is a significant public health problem. Continuing propagation in endemic settings and emerging regional outbreaks have indicated the need for comprehensive and coordinated HIV prevention. We describe the development of a conceptual framework and calibration of an agent-based model (ABM) to examine how combinations of interventions may reduce and potentially eliminate HIV transmission among drug-using populations.

METHODOLOGY/PRINCIPAL FINDINGS

A multidisciplinary team of researchers from epidemiology, sociology, geography, and mathematics developed a conceptual framework based on prior ethnographic and epidemiologic research. An ABM was constructed and calibrated through an iterative design and verification process. In the model, "agents" represent IDU, NIDU, and non-drug users who interact with each other and within risk networks, engaging in sexual and, for IDUs, injection-related risk behavior over time. Agents also interact with simulated HIV prevention interventions (e.g., syringe exchange programs, substance abuse treatment, HIV testing) and initiate antiretroviral treatment (ART) in a stochastic manner. The model was constructed to represent the New York metropolitan statistical area (MSA) population, and calibrated by comparing output trajectories for various outcomes (e.g., IDU/NIDU prevalence, HIV prevalence and incidence) against previously validated MSA-level data. The model closely approximated HIV trajectories in IDU and NIDU observed in New York City between 1992 and 2002, including a linear decrease in HIV prevalence among IDUs. Exploratory results are consistent with empirical studies demonstrating that the effectiveness of a combination of interventions, including syringe exchange expansion and ART provision, dramatically reduced HIV prevalence among IDUs during this time period.

CONCLUSIONS/SIGNIFICANCE

Complex systems models of adaptive HIV transmission dynamics can be used to identify potential collective benefits of hypothetical combination prevention interventions. Future work will seek to inform novel strategies that may lead to more effective and equitable HIV prevention strategies for drug-using populations.

HIV infection and risk of overdose: a systematic review and meta-analysis

Drug overdose is a common cause of non-AIDS death among people with HIV and the leading cause of death for people who inject drugs. People with HIV are often exposed to opioid medications during their HIV care experience; others may continue to use illicit opioids despite their disease status. In either situation, there may be a heightened risk for nonfatal or fatal overdose. The potential mechanisms for this elevated risk remain controversial. We systematically reviewed the literature on the HIV-overdose association, meta-analyzed results, and investigated sources of heterogeneity, including study characteristics related to hypothesize biological, behavioral, and structural mechanisms of the association. Forty-six studies were reviewed, 24 of which measured HIV status serologically and provided data quantifying an association. Meta-analysis results showed that HIV seropositivity was associated with an increased risk of overdose mortality (pooled risk ratio 1.74, 95% confidence interval 1.45, 2.09), although the effect was heterogeneous (Q = 80.3, P < 0.01, I(2) = 71%). The wide variability in study designs and aims limited our ability to detect potentially important sources of heterogeneity. Causal mechanisms considered in the literature focused primarily on biological and behavioral factors, although evidence suggests structural or environmental factors may help explain the greater risk of overdose among HIV-infected drug users. Gaps in the literature for future research and prevention efforts as well as recommendations that follow from these findings are discussed.

Self-reported drug use and mortality among a nationwide sample of Swedish conscripts - a 35-year follow-up

BACKGROUND

Drug users in clinical samples have elevated mortality compared with the general population, but little is known about mortality among users of drugs within the general population.

AIM

To determine whether self-reported use of illicit drugs and non-prescribed sedatives/hypnotics among young men in the general population is related to mortality.

METHODS

A 35-year follow-up of 48024 Swedish men, born 1949-1951 and conscripted in 1969/1970, among whom drug use was reported by 8767 subjects. Cross-record linkage was effected between individual data from the Swedish conscription and other national registers. Deaths and causes of death/1000 person-years were calculated. Cox PH regression was used to estimate hazard ratios (HRs) for death with 95% confidence intervals (95% CIs). An HR was calculated for users of different dominant drugs at conscription compared with non-users by age interval, after adjusting for confounders and hospitalisation with a drug-related diagnosis.

RESULTS

Drug users showed elevated mortality (HR 1.61, p<0.05) compared with non-users. After adjusting for risk factors, users of stimulants (HR 4.41, p<0.05), cannabis (HR 4.27, p<0.05), opioids (HR 2.83, p>0.05), hallucinogens (HR 3.88, p<0.05) and unspecified drugs (HR 4.62, p<0.05) at conscription with a drug-related diagnosis during follow-up showed an HR approaching the standard mortality ratios in clinical samples. Among other drug users (95.5%), only stimulant users showed statistically significantly increased mortality (HR 1.96, p<0.05).

CONCLUSIONS

In a life-time perspective, drug use among young men in the general population was a marker of premature death, even a long time after exposure.

Genome-wide association scan in HIV-1-infected individuals identifying variants influencing disease course

Background

AIDS develops typically after 7–11 years of untreated HIV-1 infection, with extremes of very rapid disease progression (<2 years) and long-term non-progression (>15 years). To reveal additional host genetic factors that may impact on the clinical course of HIV-1 infection, we designed a genome-wide association study (GWAS) in 404 participants of the Amsterdam Cohort Studies on HIV-1 infection and AIDS.

Methods

The association of SNP genotypes with the clinical course of HIV-1 infection was tested in Cox regression survival analyses using AIDS-diagnosis and AIDS-related death as endpoints.

Results

Multiple, not previously identified SNPs, were identified to be strongly associated with disease progression after HIV-1 infection, albeit not genome-wide significant. However, three independent SNPs in the top ten associations between SNP genotypes and time between seroconversion and AIDS-diagnosis, and one from the top ten associations between SNP genotypes and time between seroconversion and AIDS-related death, had P-values smaller than 0.05 in the French Genomics of Resistance to Immunodeficiency Virus cohort on disease progression.

Conclusions

Our study emphasizes that the use of different phenotypes in GWAS may be useful to unravel the full spectrum of host genetic factors that may be associated with the clinical course of HIV-1 infection.

Mortality among cocaine users: a systematic review of cohort studies

AIMS

To conduct a systematic review of mortality among cohort studies of cocaine users.

METHODS

Three electronic databases were searched (EMBASE, Medline and PsychINFO); other online databases were searched using online libraries and repositories of reports and literature in the drug and alcohol field, with requested contributions from trained librarians and experts. Searches and extraction were undertaken using protocols and cross-checking of decisions by two authors. Additional data were requested from study investigators where studies did not report relevant data.

RESULTS

1911 articles and 2 reports were identified from searches, with data from another four studies located from review articles. Seven cohorts of "problem" or dependent cocaine users reported data that permitted mortality rates to be estimated. Crude mortality rates ranged from 0.53 (95% CI: 0.10-1.58) to 6.16 (95% CI: 5.21-7.11) per 100 PY. Standardised mortality ratios (SMRs) reported in four studies suggested that mortality was four to eight times higher among cocaine users than age and sex peers in the general population.

CONCLUSIONS

There are limited data on the extent of elevated mortality among problematic or dependent cocaine users and it is unclear how generalisable the results of these studies may be to other populations of problematic cocaine users. Greater attention to both the method of recruitment, and the characteristics of cocaine users, would enhance our understanding of the mortality risks of problematic cocaine use.

Diazepam leads to enhanced severity of orthopoxvirus infection and immune suppression

Benzodiazepines are drugs widely used as tranquilizers and in various other indications. We treated Balb/c mice with diazepam and infected them with cowpox (CPXV) and vaccinia virus (VACV). Disease index, weight loss and the antibody response were determined. Additionally the influence of different benzodiazepines on the mitogen response of human peripheral blood lymphocytes and spleen cells was tested. Diazepam led to earlier disease onset, prolonged duration of symptoms, higher weight loss and overall disease index in VACV infected mice. CPXV infected mice developed poxviral skin lesions only after drug administration and a significant decrease in the specific antibody response was also observed. Diazepam and alprazolam also inhibited the proliferative response of human lymphocytes/spleen cells in vitro but did not show noteworthy apoptotic effects. It is surprising that even a single dose of diazepam has a profound influence on the immune system, sufficient to facilitate symptomatic infectious disease. These data provide first evidence that commonly used drugs like Valium^® may augment severity of rare poxvirus infections such as CPXV or monkeypox. As VACV is still used as life vaccine against smallpox there is also a risk of enhanced side effects or possible interference with the success of vaccination.

Evidence for the effectiveness of sterile injecting equipment provision in preventing hepatitis C and human immunodeficiency virus transmission among injecting drug users: a review of reviews

AIMS

To review the evidence on the effectiveness of harm reduction interventions involving the provision of sterile injecting equipment in the prevention of hepatitis C virus (HCV) and human immunodeficiency virus (HIV) transmission among injecting drug users (IDUs). The interventions assessed were needle and syringe programmes (NSP), alternative modes of needle/syringe provision (pharmacies, vending machines and outreach) and the provision of injecting equipment other than needles/syringes.

METHODS

Systematic searches of the English language literature to March 2007 were undertaken to identify systematic, narrative or meta-analytical reviews (also known as a review of reviews) of the impact of interventions on HCV transmission, HIV transmission or injecting risk behaviour (IRB). Critical appraisal criteria classified the reviews as either high quality ('core') or supplementary: a framework based on the quality of reviews, the reviewers' conclusions and the designs/findings of the primary studies was used to derive evidence statements.

RESULTS

Three core and two supplementary reviews of injecting equipment interventions were identified. According to the proposed framework, this study found (a) insufficient evidence to conclude that any of the interventions are effective in preventing HCV transmission; (b) tentative evidence to support the effectiveness of NSP in preventing HIV transmission; (c) sufficient evidence to support the effectiveness of NSP (and tentative evidence of an additional impact of pharmacy NSP) in reducing self-reported IRB; and (d) little to no evidence on vending machines, outreach or providing other injecting equipment in relation to any of the outcomes.

CONCLUSIONS

The evidence is weaker than given credit for in the literature. The lack of evidence for effectiveness of NSP vis-à-vis biological outcomes (HCV and HIV incidence/prevalence) reflects the limitations of studies that have been undertaken to investigate these associations. Particularly for HCV, low levels of IRB may be insufficient to reduce high levels of transmission. New studies are required to identify the intervention coverage necessary to achieve sustained changes in blood-borne virus transmission.

Mortality among amphetamine users: a systematic review of cohort studies

AIMS

To report the results of a comprehensive literature search of studies of mortality among people who use amphetamines.

DESIGN AND SETTING

Three electronic databases were searched (EMBASE, Medline and PsycINFO) and "grey" literature was located. Shortlists of papers were circulated to experts to ascertain whether any important papers had been missed. Papers were hand-searched to retrieve any additional relevant articles.

MEASUREMENTS

Studies meeting inclusion criteria were prospective cohort studies examining mortality risk among dependent and problematic amphetamine users. Crude mortality rates (CMR/100PY) and standardised mortality ratios (SMRs) were the primary outcome measures considered. Data on overall mortality, and rates for specific causes of death, were of interest.

FINDINGS

2187 articles and 9 grey literature sources were obtained. After thorough review, 72 articles were identified as reporting on amphetamine-related mortality, 7 provided data from cohort studies of users. An additional study of Swedish military conscripts was identified by the authors during correspondence with other researchers. The geographic spread of cohorts was restricted to high income countries with the exception of one Thai study; reporting of standard parameters in mortality studies was often sparse. The estimated CMRs ranged from 0 in Australia to 2.95 (1.46-4.59) in Thailand. The Czech cohort reported the only SMR: 6.22 overall, males: 5.87, females: 7.84.

CONCLUSIONS

Given the widespread use of amphetamines, the known non-fatal adverse effects of use and the mortality rates reported here, cohort studies investigating the morbidity and mortality associated with such drug use should be a research priority.

Factors associated with premature mortality among young injection drug users in Vancouver

BACKGROUND

Young injection drug users (IDUs) may be at increased risk of premature mortality due to the health risks associated with injection drug use including overdoses and infections. However, there has been little research conducted on mortality causes, rates and associations among this population. We undertook this study to investigate patterns of premature mortality, prior to age 30 years, among young IDUs.

METHODS

Since 1996, 572 young (< or = 29 years) IDUs have been enrolled in the Vancouver Injection Drug Users Study (VIDUS). Semi-annually, participants have completed an interviewer-administered questionnaire and have undergone serologic testing for HIV and hepatitis C (HCV). Mortality data have been continually updated through linkages with the Provincial Coroner's Office. Crude and age-specific mortality rates, standardized mortality ratios, and life expectancy measures were calculated using person-time methods. Predictors of mortality were identified using Cox regression analyses.

FINDINGS

Twenty-two participants died prior to age 30 years during the follow-up period for an overall crude mortality rate of 1,368 per 100,000 person-years. Overall, young IDUs were 16.4 times (95% confidence interval [CI]; 9.1-27.1) more likely to die; young women IDUs were 54.1 times (95%CI; 29.6-90.8) and young men IDUs were 12.9 times (95%CI; 5.5, 25.3) more likely to die when compared to the Canadian non-IDU population of the same age. The leading observed cause of death among females was: homicide (N = 9); and among males: suicide (N = 3) and overdose (N = 3). In Cox regression analyses, factors associated with mortality were, HIV infection (Hazard Ratio [HR]: 4.55; CI: 1.92-10.80) and sex work (HR: 2.76; CI: 1.16-6.56).

INTERPRETATION

Premature mortality was 13 and 54 times higher among young men and women who use injection drugs in Vancouver than among the general population in Canada. The majority of deaths among the women were attributable to homicide, suggesting that interventions should occur not only through harm reduction services but also through structural interventions at the legal and policy level.

Effect of education on overall and cause-specific mortality in injecting drug users, according to HIV and introduction of HAART

BACKGROUND

We assessed the impact of education on long-term overall and cause-specific mortality among 6575 injecting drug users (IDUs) according to HIV status and introduction of highly active antiretroviral therapy (HAART).

METHODS

Community-based cohort study of IDUs recruited in three AIDS prevention centres (1987-1996). Causes of death were ascertained in clinical centres and Mortality Registry and classified as AIDS, drug use related, injuries, or liver diseases. Poisson regression models including education and calendar period interaction and adjusted by sex, age, and HIV were used.

RESULTS

In 73 901 person-years of follow-up, there were 1493 deaths (20.2/1000 person-years): 761 related to AIDS, 234 to drug use, 179 to injuries, and 93 to liver diseases. IDUs with university studies had a lower risk of death (RR 0.52; 95% CI 0.36-0.77) than those without studies: this difference was higher after (RR 0.45; 95% CI 0.25-0.80) than before 1997 (RR 0.68; 95% CI 0.41-1.13). Compared to before 1997, while decreases in the risk of AIDS mortality were seen during 1997-2004 for both lower (RR 0.49; 95% CI 0.41-0.58) and higher (RR 0.33; 95% CI 0.23-0.48) educated, only those higher educated experienced a reduction in drug-use mortality (RR 0.54; 95% CI 0.28-1.05) and death from injuries (RR 0.52; 95% CI 0.23-1.21).

CONCLUSIONS

Independently of HIV status, lower education predicts a higher risk of death in IDUs and its impact is stronger after 1997. Education has a protective effect on most causes of death and it cannot be entirely attributable to the access or use of HAART.

Using cohort studies to estimate mortality among injecting drug users that is not attributable to AIDS

BACKGROUND

Injecting drug use (IDU) and associated mortality appear to be increasing in many parts of the world. IDU is an important factor in HIV transmission. In estimating AIDS mortality attributable to IDU, it is important to take account of premature mortality rates from other causes to ensure that AIDS related mortality among injecting drug users (IDUs) is not overestimated. The current review provides estimates of the excess non-AIDS mortality among IDUs.

METHOD

Searches were conducted with Medline, PsycINFO, and the Web of Science. The authors also searched reference lists of identified papers and an earlier literature review by English et al (1995). Crude mortality rates (CMRs) were derived from data on the number of deaths, period of follow up, and number of participants. In estimating the all-cause mortality, two rates were calculated: one that included all cohort studies identified in the search, and one that only included studies that reported on AIDS deaths in their cohort. This provided lower and upper mortality rates, respectively.

RESULTS

The current paper derived weighted mortality rates based upon cohort studies that included 179 885 participants, 1,219,422 person-years of observation, and 16,593 deaths. The weighted crude AIDS mortality rate from studies that reported AIDS deaths was approximately 0.78% per annum. The median estimated non-AIDS mortality rate was 1.08% per annum.

CONCLUSIONS

Illicit drug users have a greatly increased risk of premature death and mortality due to AIDS forms a significant part of that increased risk; it is, however, only part of that risk. Future work needs to examine mortality rates among IDUs in developing countries, and collect data on the relation between HIV and increased mortality due to all causes among this group.

Do young heroin users in Madrid, Barcelona and Seville have sufficient knowledge of the risk factors for unintentional opioid overdose?

To identify the self-perceived reasons for unintentional opioid overdose of young heroin users in three Spanish cities and their agreement with objective risk factors for overdose. Computer-Assisted Personal Interviews (CAPI) were held with 991 street-recruited current heroin users aged 18-30. The general reasons for overdose and the reasons for the last overdose suffered were explored with open-ended (OEQs) and pre-coded questions (PCQs). Limited knowledge of overdose risk factors was defined as mention of fewer than two objective risk factors for unintentional overdose in the OEQ. Univariate, bivariate, and logistic regression methods were used. 77.8% (Seville), 64.9% (Madrid) and 57.2% (Barcelona) of participants have limited knowledge of overdose risk factors. Residence in Seville and not having attended courses or meetings on overdoses were significantly associated with limited knowledge, after adjusting for other factors. The most frequently identified general reasons in OEQ or PCQ were using heroin in large amounts (66.8%), together with tranquilizers (62.0%), adulterated (60.7%), or purer than usual (57.6%). Most reasons were selected more frequently in PCQ than in OEQ, especially rapid injection of the entire dose and using heroin shortly after using tranquilizers or alcohol, by injection, or after a period of abstinence. The results were similar for overdoses suffered by participants. Most young heroin users do not have sufficient knowledge of overdose risk factors, especially the use of heroin by injection, after a period of abstinence, or together with alcohol or methadone. Specific informational or educational programs adapted to the local context are critically needed.

Do needle syringe programs reduce HIV infection among injecting drug users: a comprehensive review of the international evidence

This first international review of the evidence that needle syringe programs reduce HIV infection among injecting drug users found that conservative interpretation of the published data fulfills six of the nine Bradford Hill criteria (strength of association, replication of findings, temporal sequence, biological plausibility, coherence of evidence, and reasoning by analogy) and all six additional criteria (cost-effectiveness, absence of negative consequences, feasibility of implementation, expansion and coverage, unanticipated benefits, and application to special populations). The Bradford Hill criteria are often used to evaluate public health interventions. The principal finding of this review was that there is compelling evidence of effectiveness, safety, and cost-effectiveness, consistent with seven previous reviews conducted by or on behalf of U.S. government agencies. Authorities in countries affected or threatened by HIV infection among injecting drug users should carefully consider this convincing evidence now available for needle syringe programs with a view to establishing or expanding needle syringe programs to scale.

VEdeTTE, a longitudinal study on effectiveness of treatments for heroin addiction in Italy: study protocol and characteristics of study population

The aim of this study was to provide a methodological overview of the study design of the national evaluation large-scale study VEdeTTE and a description of the VEdeTTE study population and to compare enrollments with refusals and the study population with the overall clients at the National Health System (NHS) treatment centers. VEdeTTE is a longitudinal study of heroin addicts recruited in 115 NHS treatment centers in Italy, 1998-2001; 11,903 people were enrolled, 3876 refused to participate; data were analysed on 10,454. Information from refusals was compared to enrollments. The characteristics of the cohort were compared to those of all patients treated in 1999 in Italy. Refusals had a lower educational level and less regular occupational status than those enrolled. Fourteen percent of enrolled patients were women; heroin users in the VEdeTTE study were older than patients attending all NHS treatment centers in Italy; incident cases were less represented. The majority of participants had more than 8 years of education, 33.5% were regularly employed, and only 2% did not have a fixed address. Injectors were 72.3%; 40.6% had a previous overdose, and 14.3% had been imprisoned for life; 15.7% shared injection equipment during the previous 6 months. The proportion of participants reporting heroin use approximately halved from the beginning of the current treatment to the time of the interview. The VEdeTTE study is the biggest cohort of heroin addicts attending treatment centers in Europe. The Italian heroin-addicted population under treatment seems to have low level of education but good social integration. Compared with men, women show a higher severity. Participants show a beneficial effect of treatment.

Drug-related mortality and its impact on adult mortality in eight European countries

OBJECTIVE

To estimate the mortality rates from drug-related deaths and other causes among problem drug users and population attributable risk of death due to opiate use in eight study sites in Europe.

METHODS

Opiate users were recruited from drug treatment centres during the period 1990-1998 and deaths followed up through national or local mortality registries. Gender-specific overall mortality rate, proportion of deaths by cause (drug-related, HIV, other), standardized mortality ratios (SMRs), and the attributable risk fraction (ARF) were estimated.

RESULTS

Crude mortality rates varied from 1 per 100 person-years in the Dublin and London cohorts to 3.8 per 100 person-years in Barcelona. The highest drug-related mortality rate was 10 per 1,000 person-years in Barcelona; the rates were approximately 7 per 1,000 person-years in Denmark, London, Rome, and Vienna, and <3.5 per 1,000 person-years for the others cohorts. The mortality rate for AIDS was <2 per 1,000 person-years in all the cohorts except Lisbon, Rome, and Barcelona, for which it was approximately 6 per 1,000 person-years. The highest SMR among males was 21.1 in Barcelona, and among females the highest SMRs were 53.7 and 37.7 in Barcelona and Rome, respectively. In Denmark the ARF was 5%, whereas it was >10% in all other study sites and 24% in Barcelona.

CONCLUSION

Cohort mortality studies, especially in combination with estimates of prevalence, provide useful insights into the impact of opiate use on mortality across European countries and emphasize how preventing overall and drug-related deaths among opiate users can significantly improve the health of the population.

Evaluating the impact of methadone maintenance programmes on mortality due to overdose and aids in a cohort of heroin users in Spain

AIMS

To assess the relationship between methadone treatment (MT) and overdose and HIV/AIDS mortality among heroin users resident in Barcelona city.

DESIGN

All patients who started treatment in any treatment centre between 1992 and 1997 were included in a cohort the first time they were admitted for heroin addiction treatment. Follow-up controls were carried out every 9 months, on average, until 31 December 1999. Variables, both constant and varying over time, were fitted into Cox regression models.

FINDINGS

The study recruited 5049 patients, which provided 23,048.2 person-years. Fifty per cent were in MT during the study period; of the total cohort 1005 patients died: 38.4% due to AIDS, 34.7% to overdose and 27% to other causes. Overall mortality decreased from 5.9 deaths per 100 person-years in 1992 to 1.6 in 1999. Globally, life expectancy at birth was 39 years, 38 years lower than that of the general population. The main factor for overdose mortality was not being in MT at the time of death [relative ratio (RR) = 7.1]; other factors were being a current injector at baseline and being HIV positive. For AIDS mortality, the main factor was the calendar year (RR for 1996 versus 1999 = 4.6), the next major factor was more than 10 years of heroin consumption, followed by not being in MT, being unemployed, then having a prison record.

CONCLUSIONS

The observed mortality decline could be linked to the effectiveness of low-threshold MT. The life expectancy of heroin users increased by 21 years during the study period.

The effect of HIV infection on overdose mortality

OBJECTIVES

To quantify the association of HIV infection with overdose mortality and explore the potential mechanisms.

DESIGN

A prospective cohort study.

METHODS

A total of 1927 actively injecting drug users who were HIV seronegative at baseline, of whom 308 later HIV seroconverted, were followed semi-annually for death from 1988 to 2001. Survival analyses using marginal structural and standard Cox models were used to evaluate the effect of HIV infection on the risk of overdose mortality.

RESULTS

Overdose death rates were higher in HIV-seropositive than HIV-seronegative drug users: 13.9 and 5.6 per 1000 person-years, respectively (P < 0.01). The hazard ratio (HR) was 2.54 [95% confidence interval (CI) 1.47, 4.38] for the marginal structural model and 2.06 (95% CI 1.25, 3.38) for the standard Cox model, both adjusted for demographics, drug injection characteristics, alcohol abuse, substance abuse treatment, and sexual orientation. Adjusting for possible time-varying mediators (i.e. drug use, medical conditions and healthcare access) in extended marginal structural models reduced the effect of HIV on overdose mortality by 30% (HR 1.82, 95% CI 1.01, 3.30). Abnormal liver function was associated with a higher risk of overdose mortality (HR 2.00, 95% CI 1.05, 3.84); adjustment for this further reduced the effect of HIV on overdose mortality.

CONCLUSION

HIV infection was associated with a higher risk of overdose mortality. Drug use behavior, systematic disease and liver damage associated with HIV infection appeared to account for a substantial portion of this association. The data suggest a group to target with interventions to reduce overdose mortality rates.

Potential cost-effectiveness of a preventive hepatitis C vaccine in high risk and average risk populations in Canada

Hepatitis C virus (HCV) vaccine development remains at an early stage. We explored the economic and health consequences of potential HCV vaccines by comparing universal vaccination with a hepatitis C vaccine to no vaccination in two groups: (1) injecting drug users (IDU); (2) all 12 year olds, using a Markov cohort simulation. Among IDUs, vaccination would avert 248 cases of HCV infection and 89 HCV-related deaths per 1000 individuals, and reduce costs. In average risk cohorts, vaccination did not reduce costs but was reasonably cost effective. These results provide encouragement to vaccine developers that a vaccine that is moderately effective and reasonably priced should not face economic barriers to implementation and will be attractive to third party payers.

Association of alcohol and drug use disorders and completed suicide: an empirical review of cohort studies

BACKGROUND

This study updated and expanded upon Harris and Barraclough's empirical review [Harris, E.C., Barraclough, B., 1997. Suicide as an outcome for mental disorders. A meta-analysis, Br. J. Psychiatry 170, 205-228] of retrospective and prospective cohort studies of alcohol and drug use disorders and suicide.

METHOD

Studies presenting data on alcohol and drug use disorders and suicide originally identified by Harris and Barraclough were used in this study. To find additional studies, (1) the location of English language reports on MEDLINE (1994-2002) were identified with the search terms 'substance-disorders' with 'mortality' and 'follow-up', (2) read throughs were conducted of four prominent alcohol and drug specialty journals from 1966 through 2002, and (3) the reference sections of studies that met criteria were searched for additional reports. This strategy yielded 42 new studies meeting eligibility criteria.

RESULTS

The estimated standardized mortality ratios (SMR; 95% confidence interval) for suicide were as follows: alcohol use disorder (979; 95% CI 898-1065; p < 0.001), opioid use disorder (1351; 95% CI 1047-1715; p < 0.001), intravenous drug use (1373; 95% CI 1029-1796; p < 0.001), mixed drug use (1685; 95% CI 1473-1920; p < 0.001), heavy drinking (351; 95% CI 251-478; p < 0.001). SMR estimates stratified by sex were also calculated.

CONCLUSIONS

Additional studies on the association of suicide and mixed drug use, heavy drinking, and alcohol use disorders in women augmented the findings of Harris and Barraclough, along with a novel estimate for intravenous drug use, a byproduct of intensive research on HIV in the past decade. There is a large empirical literature on alcohol use disorders and suicide and a moderate literature on suicide and opioid use disorders and IV drug use. There remains limited prospective data on the association of suicide and other drug use disorders (e.g., cocaine, cannabis).

Mortality risk among new onset injection drug users

AIMS

To characterize mortality experience among those who only recently started injection.

DESIGN

Prospective study.

SETTING

Independent study clinic within high drug use neighborhoods.

PARTICIPANTS

In 1988-1989, we enrolled 256 adult injection drug users (IDUs) recruited through street outreach who had initiated injection within the prior 2 years.

MEASUREMENTS

Consenting participants underwent venipuncture for HIV antibody testing and interviews. We prospectively ascertained date and cause of death through follow-up contact and registry linkages. Analyses included standardized mortality ratios (SMRs) with local, state and national mortality data, adjusted for age, gender and race.

FINDINGS

Baseline median age was 30 years, 70% were male, 95% were African-American and 90% injected within the prior 6 months. We identified 69 deaths through October 2000; mortality rate was 3.3/100 person-years. The adjusted SMR with the USA (and Baltimore) as the reference for IDUs was 4.40 (2.43) for 1991-1992, which increased to 8.12 (4.13) by 1993-1994, decreased to 4.43 (2.13) by 1997-1998 and increased slightly to 5.35 (2.79) during 1999-2000. Excluding HIV-related mortality, SMRs remained elevated. Decline in SMRs was not linked to drug abuse treatment.

CONCLUSIONS

These data demonstrate excess mortality among new-onset IDUs compared with demographically similar peers in the general population, indicating the need for interventions to prevent premature death among young IDUs.

Increased mortality associated with HTLV-II infection in blood donors: a prospective cohort study

Background

HTLV-I is associated with adult T-cell leukemia, and both HTLV-I and -II are associated with HTLV-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Several published reports suggest that HTLV-I may lead to decreased survival, but HTLV-II has not previously been associated with mortality.

Results

We examined deaths among 138 HTLV-I, 358 HTLV-II, and 759 uninfected controls enrolled in a prospective cohort study of U.S. blood donors followed biannually since 1992. Proportional hazards models yielded hazard ratios (HRs) for the association between mortality and HTLV infection, controlling for sex, race/ethnicity, age, income, educational level, blood center, smoking, injection drug use history, alcohol intake, hepatitis C status and autologous donation. After a median follow-up of 8.6 years, there were 45 confirmed subject deaths. HTLV-I infection did not convey a statistically significant excess risk of mortality (unadjusted HR 1.9, 95%CI 0.8–4.4; adjusted HR 1.9, 95%CI 0.8–4.6). HTLV-II was associated with death in both the unadjusted model (HR 2.8, 95%CI 1.5–5.5) and in the adjusted model (HR 2.3, 95%CI 1.1–4.9). No single cause of death appeared responsible for the HTLV-II effect.

Conclusions

After adjusting for known and potential confounders, HTLV-II infection is associated with increased mortality among healthy blood donors. If replicated in other cohorts, this finding has implications for both HTLV pathogenesis and counseling of infected persons.

Hospitalization for depressive syndrome in a cohort of HIV-infected patients contaminated through injecting drug use: MANIF 2000 cohort, France, 1995-1999

The objective of this study was to estimate the relative impact of hospitalization for depressive syndrome (DS) on all causes of hospitalization and characterize individuals more likely to experience hospitalization for DS in the French cohort study, Manif 2000, of patients HIV infected through injection drug use. We selected all patients followed-up to the 24-month visit (C24) who missed no more than one visit. Using medical records, dates and causes of hospitalizations, were collected retrospectively. A Poisson regression model based on generalized estimating equations was used to identify factors associated with hospitalization for DS. During the study period, 223 hospitalizations were recorded for 120 of the 335 selected patients. DS was the second reason for hospitalization after infections, accounting for 14.3% of the total number of hospitalizations. DS was reported in 32 hospitalizations and involved 24 patients, five of them being hospitalized more than once for the same cause. Factors independently associated with hospitalization for DS were history of multiple incarceration (RR = 2.1, 95% CI: 1.0-4.7), polydrug use (RR = 2.6, 95% CI: 1.1 -5.9) and lack of stable relationship (RR = 4.2, 95% CI: 1.6- 11. 1). In the HAART era, DS represents an important cause of hospitalization of HIV-infected injecting drug users, mainly concerning patients presenting no stable relationship and signs of social instability. Scheduled psychiatric consultations for these patients would permit us to identify those for whom major depression might lead to hospitalization and provide them with timely and appropriate care.

Reasons for selecting an initial route of heroin administration and for subsequent transitions during a severe HIV epidemic

AIM

To identify the most important reasons for selecting a particular route of heroin administration and for subsequent transitions during a period of epidemic HIV transmission. To study temporal trends in these reasons.

DESIGN

Cross-sectional survey.

PARTICIPANTS

Nine hundred heroin users in three Spanish cities: 305 in Seville, 297 in Madrid and 298 in Barcelona.

MEASUREMENTS

A separate analysis was made of the reasons for five types of behaviour: (a) selecting injection as the initial usual route of heroin administration (URHA); (b) changing the URHA to injection; (c) never having injected drugs; (d) selecting the smoked or sniffed route as the initial URHA; and (e) changing the URHA to a non-injected route. Subjects were invited to evaluate the importance of each reason included in a closed list. Spontaneously self-perceived reasons were also explored in an open-ended question for each of the five types of behaviour studied.

FINDINGS

The primary reason selected for each type of behaviour was: (a) pressure of the social environment; (b) belief that injection is a more efficient route than smoking or sniffing heroin; (c) concern about health consequences (especially fears of HIV and overdose), and fear of blood or of sticking a needle into one's veins; (d), pressure of the social environment and (e) concern about health consequences and vein problems. For women, having a sexual partner who injected heroin played a decisive role in initiating or changing to injection. Few people spontaneously mentioned market conditions for purchasing heroin as an important reason for any behaviour, nor did many mention risk of overdose as reasons for (c) or (d).

CONCLUSIONS

These findings should be considered when designing interventions aimed at preventing initiation of injecting or facilitating the transition to non-injected routes.

Anti-human immunodeficiency virus-1 antibody titers in injection drug users compared to sexually infected individuals

Sera from infected injection drug users (IDU) have shown to have antibodies against synthetic human immunodeficiency virus-1 (HIV-1) envelope peptides more frequently. In this study, reactivity of 48 IDU plasma were compared to 60 plasmas obtained from sexually infected individuals (S). The overall reactivity of plasma from IDU compared to S was higher, and the reactivity titers were much higher for IDU plasma than S. IDU plasma also showed a broader antibody response. The higher reactivity titers were observed mainly for the gp41 immunodominant epitope and V3 peptides corresponding to the consensus sequences of HIV-1 subtypes/variants prevalent in Brazil (B, F, C) indicating the specificity in the higher immune response of IDU.

Suicide among heroin users: rates, risk factors and methods

The current paper examines critically the literature on suicide rates, suicide risk factors and methods employed for suicide among heroin users, and compares these to those of the general population. Heroin users have a death rate 13 times that of their peers, and deaths among heroin users attributed to suicide range from 3-35%. Overall, heroin users are 14 times more likely than peers to die from suicide. The prevalence of attempted suicide is also many orders of magnitude greater than that of community samples. The major general population risk factors for suicide also apply to heroin users (gender, psychopathology, family dysfunction and social isolation). Heroin users, however, have extremely wide exposure to these factors. They also carry additional risks specifically associated with heroin and other drug use. Drugs as a method of suicide play a larger role in suicide among heroin users than in the general population. Heroin, however, appears to play a relatively small role in suicide among this group. Overall, suicide is a major clinical issue among heroin users. It is concluded that suicide is a major problem that treatment agencies face, and which requires targeted intervention if the rates of suicide among this group are to decline.

Changes in the cause of death among HIV positive subjects across Europe: results from the EuroSIDA study

OBJECTIVES

The causes of death among HIV-positive patients may have changed since the introduction of highly active antiretroviral therapy (HAART). We investigated these changes, patients who died without an AIDS diagnosis and factors relating to pre-AIDS deaths.

METHODS

Analyses of 1826 deaths among EuroSIDA patients, an observational study of 8556 patients. Incidence rates of pre-AIDS deaths were compared to overall rates. Factors relating to pre-AIDS deaths were identified using Cox regression.

RESULTS

Death rates declined from 15.6 to 2.7 per 100 person-years of follow-up (PYFU) between 1994 and 2001. Pre-AIDS incidence declined from 2.4 to 1.1 per 100 PYFU. The ratio of overall to pre-AIDS deaths peaked in 1996 at 8.4 and dropped to < 3 after 1998. The adjusted odds of dying following one AIDS defining event (ADE) increased yearly (odds ratio, 1.53; P < 0.001), conversely the odds of dying following three or more ADE decreased yearly (odds ratio, 0.79; P < 0.001). The proportion of deaths that followed an HIV-related disease decreased by 23% annually; in contrast there was a 32% yearly increase in the proportion of deaths due to known causes other than HIV-related or suicides. Injecting drug users (IDU) were significantly more likely to die before an ADE than homosexuals (relative hazard, 2.97; P < 0.0001) and patients from northern/eastern Europe (relative hazard, 2.01; P < 0.0001) were more likely to die pre-AIDS than southern patients.

CONCLUSIONS

The proportion of pre-AIDS deaths increased from 1994 to 2001; however, the incidence of pre-AIDS deaths and deaths overall declined. IDU and subjects from northern/eastern Europe had an increased risk of pre-AIDS death. HIV-positive patients live longer therefore it is essential to continue to monitor all causes of mortality to identify changes.

An increase in overdose mortality during the first 2 weeks after entering or re-entering methadone treatment in Amsterdam

AIMS

It has been suggested that starting and temporarily discontinuing methadone treatment is related to an increased risk in overdose mortality. This study describes the incidence of overdose mortality in relation to time after (re)entering or leaving treatment.

DESIGN

A dynamic cohort of 5200 Amsterdam methadone clients was observed during treatment and (a maximum of 1 year) after treatment.

FINDINGS

Between 1986 and 1998, 29,729 person-years (py) and 68 overdose deaths were recorded, leading to an overdose mortality rate of 2.3/1000 py (2.2 during and 2.4 after treatment). A modest increase was observed during the first 2 weeks after (re)entering treatment; 6.0/1000 py (rate ratio: 2.9; 95% confidence interval 1.4; 5.8). Directly after leaving treatment no increase was observed.

CONCLUSIONS

Inhaling heroin, common among Amsterdam heroin users, is thought to account for low OD mortality rates both during and after treatment. Accumulation of methadone, inadequate assessment of tolerance of known clients re-entering treatment and concurrent periods of stress or extreme heroin use when entering treatment are mentioned as possible explanations of the increased risk within the first 2 weeks. An Australian study reported a much higher increase. The modest increase in Amsterdam is explained by low background risk of overdose mortality, low starting dosage and the low threshold to treatment.

Impact of adherence and highly active antiretroviral therapy on survival in HIV-infected patients

OBJECTIVES

To assess the effect of antiretroviral therapy (ART) adherence on survival in HIV-infected patients.

DESIGN

Cohort study at a single hospital in Barcelona, Spain.

METHODS

Data on HIV-infected patients older than 18 years of age who began ART during the period 1990 to 1999 were analyzed. Patients were considered nonadherent if the total dose of antiretroviral drug was less than 90% of that prescribed. Adherence was assessed through self-report and hospital pharmacy appointments. Cox regression with time-dependent variables was used.

RESULTS

A total of 1219 patients were included. The first ART was with monotherapy in 23.7% of cases, with two drugs in 30.5%, and with triple therapy in 45.8%. In multivariate analysis, the variables that presented significant differences with respect to mortality were clinical stage at the beginning of treatment (AIDS: relative hazard (RH) = 2.97; 95% confidence interval [CI]: 2.14-4.13), CD4 cell count (<200 cells/microL: RH = 5.89; CI: 3.44-10.10), type of treatment (monotherapy: RH = 9.76; CI: 4.56-20.90; bi-therapy: RH = 9.12; CI: 4.23-19.64), and adherence (nonadherence: RH = 3.87; CI: 1.77-8.46).

CONCLUSIONS

The modifiable factors most strongly associated with survival were type of treatment and adherence. It would be desirable to accompany therapy with intervention strategies intended to improve adherence.

Factors associated with non-fatal heroin overdose: assessing the effect of frequency and route of heroin administration

AIMS

To examine risk factors associated with non-fatal heroin overdose, particularly frequency and route of heroin administration.

DESIGN

Data from cross-sectional surveys were analysed as a case-control and as a case cross-over design.

SETTING AND PARTICIPANTS

2556 subjects treated for heroin dependence in 164 outpatient facilities in Spain.

MEASUREMENTS

Prevalence of overdose involving emergency care in the 12 months before treatment admission. CASE CONTROL DESIGN: Odds ratio (OR) adjusted by logistic regression. CASE-CROSSOVER DESIGN: Estimated relative risk (RR) of transient risk of injecting heroin.

FINDINGS

The prevalence of overdose was 10%. In the case control analysis the cumulative risk of overdose increased as the frequency of heroin use decreased. However, among daily heroin users this risk increased as the frequency of heroin injection rose, with an OR of 6.0 (95% CI: 3.9-9.6) for daily injectors versus non-injectors. Sniffers had a higher risk than smokers among non-daily users, but not among daily users. Other factors associated with increased risk of overdose were: tranquilizers, alcohol or cocaine use, living in certain regions and being long-term HIV+ 0. In the case-crossover analysis, the RR for injecting heroin versus using other routes immediately before overdose was 15.9 (95% CI: 9.5-26.6), and was much higher for non-daily heroin users than for daily users.

CONCLUSIONS

These findings suggest that the rapid entry of a large quantity of heroin into the blood (as occurs when injecting) involves a high risk of overdose, especially when the heroin tolerance level is low (as occurs in sporadic users).