Mortality in a cohort of young primary cocaine users: controlling the effect of the riskiest drug-use behaviors

MicroRNA-423-5p Mediates Cocaine-Induced Smooth Muscle Cell Contraction by Targeting Cacna2d2

Cocaine abuse increases the risk of atherosclerotic cardiovascular disease (CVD) and causes acute coronary syndromes (ACS) and hypertension (HTN). Significant research has explored the role of the sympathetic nervous system mediating the cocaine effects on the cardiovascular (CV) system. However, the response of the sympathetic nervous system alone is insufficient to completely account for the CV consequences seen in cocaine users. In this study, we examined the role of microRNAs (miRNAs) in mediating the effect of cocaine on the CV system. MiRNAs regulate many important biological processes and have been associated with both response to cocaine and CV disease development. Multiple miRNAs have altered expression in the CV system (CVS) upon cocaine exposure. To understand the molecular mechanisms underlying the cocaine response in the CV system, we studied the role of miRNA-423-5p and its target Cacna2d2 in the regulation of intracellular calcium concentration and SMC contractility, a critical factor in the modulation of blood pressure (BP). We used in vivo models to evaluate BP and aortic stiffness. In vitro, cocaine treatment decreased miR-423-5p expression and increased Cacna2d2 expression, which led to elevated intracellular calcium concentrations and increased SMC contractility. Overexpression of miR-423-5p, silencing of its target Cacna2d2, and treatment with a calcium channel blocker reversed the elevated SMC contractility caused by cocaine. In contrast, suppression of miR-423-5p increased the intracellular calcium concentration and SMC contractibility. In vivo, smooth muscle-specific overexpression of miR-423-5p ameliorated the increase in BP and aortic stiffness associated with cocaine use. Thus, miR-423-5p regulates SMC contraction by modulating Cacna2d2 expression increasing intracellular calcium concentrations. Modulation of the miR-423-5p-Cacna2d2-Calcium transport pathway may represent a novel therapeutic strategy to improve cocaine-induced HTN and aortic stiffness.

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.

Differences in mortality in a cohort of cocaine use disorder patients with concurrent alcohol or opiates disorder

AIMS

To study mortality in a cohort of cocaine use disorder patients, and compare results in those with concurrent alcohol or opiates disorder.

DESIGN, SETTING AND PARTICIPANTS

A cohort of 10 539 cocaine use disorder individuals entering drug treatment in public out-patient centres in the city of Barcelona was followed from 1997 to 2011. Participants were divided at baseline into three groups: those with only cocaine use disorder (CUD), those with cocaine and alcohol use disorder but not opioid (CAUD) and those with cocaine and opioid use disorder (COUD). Mortality was assessed through the Spanish National Mortality Register.

MEASUREMENTS

Crude mortality rates (CMR), standardized mortality ratios (SMR) and rate ratios (RR) were calculated for each group. A multivariable Cox regression model was fitted to obtain adjusted mortality hazard ratios (aHR) of CAUD and COUD with respect to CUD. Specific mortality causes were also examined.

FINDINGS

The total of 716 deaths registered resulted in a CMR = 6.0/1000 person-years (PY); 95% confidence interval (CI) = 5.1-7.0 for CUD, CMR = 5.8/1000 PY (95% CI = 4.9-6.7) for CAUD and CMR = 20.7/1000 PY (95% CI = 18.8-22.8) for COUD, with no significant differences among sexes. Compared with the general population, mortality was four times higher (SMR = 4.1, 95% CI = 3.5-4.8) among CUD, more than three times among CAUD (SMR = 3.4, 95% CI = 2.9-3.9) and more than 10 times among COUD (SMR = 11.6, 95% CI = 10.5-12.8), being always higher in women. External injuries, led by overdose, accumulated the biggest percentage of deaths among the three groups, but infectious diseases showed the highest excess mortality. Some differences regarding causes of death were observed between the three groups.

CONCLUSIONS

Mortality risk and excess mortality are significantly greater among those with cocaine and opiates use disorder than among people with only cocaine use disorder or cocaine and alcohol use disorder.

Morbidity and mortality in homeless individuals, prisoners, sex workers, and individuals with substance use disorders in high-income countries: a systematic review and meta-analysis

BACKGROUND

Inclusion health focuses on people in extremely poor health due to poverty, marginalisation, and multimorbidity. We aimed to review morbidity and mortality data on four overlapping populations who experience considerable social exclusion: homeless populations, individuals with substance use disorders, sex workers, and imprisoned individuals.

METHODS

For this systematic review and meta-analysis, we searched MEDLINE, Embase, and the Cochrane Library for studies published between Jan 1, 2005, and Oct 1, 2015. We included only systematic reviews, meta-analyses, interventional studies, and observational studies that had morbidity and mortality outcomes, were published in English, from high-income countries, and were done in populations with a history of homelessness, imprisonment, sex work, or substance use disorder (excluding cannabis and alcohol use). Studies with only perinatal outcomes and studies of individuals with a specific health condition or those recruited from intensive care or high dependency hospital units were excluded. We screened studies using systematic review software and extracted data from published reports. Primary outcomes were measures of morbidity (prevalence or incidence) and mortality (standardised mortality ratios [SMRs] and mortality rates). Summary estimates were calculated using a random effects model.

FINDINGS

Our search identified 7946 articles, of which 337 studies were included for analysis. All-cause standardised mortality ratios were significantly increased in 91 (99%) of 92 extracted datapoints and were 11·86 (95% CI 10·42-13·30; I2=94·1%) in female individuals and 7·88 (7·03-8·74; I2=99·1%) in men. Summary SMR estimates for the International Classification of Diseases disease categories with two or more included datapoints were highest for deaths due to injury, poisoning, and other external causes, in both men (7·89; 95% CI 6·40-9·37; I2=98·1%) and women (18·72; 13·73-23·71; I2=91·5%). Disease prevalence was consistently raised across the following categories: infections (eg, highest reported was 90% for hepatitis C, 67 [65%] of 103 individuals for hepatitis B, and 133 [51%] of 263 individuals for latent tuberculosis infection), mental health (eg, highest reported was 9 [4%] of 227 individuals for schizophrenia), cardiovascular conditions (eg, highest reported was 32 [13%] of 247 individuals for coronary heart disease), and respiratory conditions (eg, highest reported was 9 [26%] of 35 individuals for asthma).

INTERPRETATION

Our study shows that homeless populations, individuals with substance use disorders, sex workers, and imprisoned individuals experience extreme health inequities across a wide range of health conditions, with the relative effect of exclusion being greater in female individuals than male individuals. The high heterogeneity between studies should be explored further using improved data collection in population subgroups. The extreme health inequity identified demands intensive cross-sectoral policy and service action to prevent exclusion and improve health outcomes in individuals who are already marginalised.

FUNDING

Wellcome Trust, National Institute for Health Research, NHS England, NHS Research Scotland Scottish Senior Clinical Fellowship, Medical Research Council, Chief Scientist Office, and the Central and North West London NHS Trust.

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.

Impact of Cocaine Use on Acute Ischemic Stroke Patients: Insights from Nationwide Inpatient Sample in the United States

Cocaine is the third most common substance of abuse after cannabis and alcohol. The use of cocaine as an illicit substance is implicated as a causative factor for multisystem derangements ranging from an acute crisis to chronic complications. Vasospasm is the proposed mechanism behind adverse events resulting from cocaine abuse, acute ischemic strokes (AIS) being one of the few. Our study looked into in-hospital outcomes owing to cocaine use in the large population based study of AIS patients. Using the national inpatient sample (NIS) database from 2014 of United States of America, we identified AIS patients with cocaine use using International Classification of Disease, Ninth Revision (ICD-9) codes. We compared demographics, mortality, in-hospital outcomes and comorbidities between AIS with cocaine use cohort versus AIS without cocaine use cohort. Acute ischemic strokes (AIS) with cocaine group consisted of higher number of older patients (> 85 years) (25.6% versus 18.7%, p <0.001) and females (52.4% versus 51.0%, p <0.001). Cocaine cohort had higher incidence of valvular disorders (13.2% versus 9.7%, p <0.001), venous thromboembolism (3.5% versus 2.6%, p<0.03), vasculitis (0.9% versus 0.4%, p <0.003), sudden cardiac death (0.4% versus 0.2%, p<0.02), epilepsy (10.1% versus 7.4%, p <0.001) and major depression (13.2% versus 10.7%, p<0.007). The multivariate logistic regression analysis found cocaine use to be the major risk factor for hospitalization in AIS cohort. In-hospital mortality (odds ratio (OR)= 1.4, 95% confidence interval= 1.1-1.9, p <0.003) and the disposition to short-term hospitals (odds ratio (OR)= 2.6, 95% confidence interval = 2.1-3.3, p <0.001) were also higher in cocaine cohort. Venous thromboembolism was observed to be linked with cocaine use (OR= 1.5, 95% confidence interval= 1.0-2.1, p < 0.01) but less severely than vasculitis (OR= 3.0, 95% confidence interval= 1.6-5.8, p <0.001). Further prospective research is warranted in this direction to improve the outcomes for AIS and lessen the financial burden on the healthcare system of the United States.

An exploratory study of information sources and key findings on UK cocaine-related deaths

Cocaine-related deaths have increased since the early 1990s in Europe, including the UK. Being multi-factorial, they are difficult to define, detect and record. The European Monitoring Centre for Drugs and Drug Addiction commissioned research to: describe trends reported to Special Mortality Registries and General Mortality Registers; provide demographic and drug-use characteristic information of cases; and establish how deaths are identified and classified. A questionnaire was developed and piloted amongst all European Monitoring Centre for Drugs and Drug Addiction Focal Point experts/Special Mortality Registries: 19 (63%) responded; nine countries provided aggregated data. UK General Mortality Registers use cause of death and toxicology to identify cocaine-related deaths. Categorisation is based on International Classification of Diseases codes. Special Mortality Registries use toxicology, autopsy, evidence and cause of death. The cocaine metabolites commonly screened for are: benzoylecgonine, ecgonine methyl ester, cocaethylene and ecgonine. The 2000s saw a generally accelerating upward trend in cases, followed by a decline in 2009. The UK recorded 2700-2900 deaths during 1998-2012. UK Special Mortality Registry data (2005-2009) indicate: 25-44 year-olds account for 74% of deaths; mean age=34 (range 15-81) years; 84% male. Cocaine overdoses account for two-thirds of cases; cocaine alone being mentioned/implicated in 23% in the UK. Opioids are involved in most (58%) cocaine overdose cases.

Crack cocaine addiction, early life stress and accelerated cellular aging among women

BACKGROUND

Early life stress (ELS) and addiction are related to age-related diseases and telomere shortening. However, the role of telomere length (TL) in crack cocaine addiction remains unknown. The purpose of this study was to investigate the TL in a sample of crack cocaine dependent-women who reported an ELS history and in a community-based sample of elderly women as a reference group for senescence.

METHODS

This study included treatment seeking crack cocaine dependents women (n=127) and elderly women without a psychiatric diagnosis (ELD, n=49). The crack cocaine sample was divided in two groups according to their Childhood Trauma Questionnaire (CTQ) scores: presence of history of childhood abuse and neglect (CRACK-ELS) and absence of ELS history (CRACK). TL was assessed by T/S ratio obtained from peripheral blood DNA using quantitative PCR assay.

RESULTS

CRACK and CRACK-ELS subjects exhibited shortened TL in comparison to the ELD group, despite their younger age. Among crack cocaine sample, CRACK-ELS group had significantly shorter telomeres than the CRACK group. Correlation analysis within crack cocaine group indicated that TL was negatively correlated with emotional abuse scores.

CONCLUSIONS

These results support previous findings associating telomere shortening with both ELS and drug addiction. This study suggests new evidence of a distinct biological phenotype for drug-dependent women with ELS. The results support the biological senescence hypothesis underpinning ELS experience.

Baseline medical comorbidities in adults randomized in the STRIDE trial for psychostimulant use disorders

BACKGROUND AND OBJECTIVES

Rates of medical illnesses may be higher among individuals with substance use disorders, complicating their care. This study aimed to expand the understanding of other medical conditions in treatment-seeking adults with stimulant use disorder (SUD) using data from Stimulant Reduction Intervention using Dose Exercise (STRIDE), a randomized, multisite trial investigating exercise augmentation of treatment as usual.

METHODS

Utilizing STRIDE baseline data, we examined demographic and clinical characteristics based on the number of self-reported diagnosed medical conditions among participants meeting eligibility criteria (passing medical screening exam and maximal exercise test, non-opioid dependent, no concomitant beta blocker, or opioid replacement therapy).

RESULTS

The majority (59%) of study participants (N = 302, mean age all participants = 39 years) did not report any history of other medical problems. Those with two or more conditions were older (mean age 46 years), reported more pain and worse physical functioning, and more psychiatric disorders (average 1.44). Hypertension was more common among participants with cocaine use disorders only (present in 16%) and liver disease was more common in those with cocaine plus other stimulant use disorders (present in 7%).

CONCLUSION AND SCIENTIFIC SIGNIFICANCE

In this sample, patients with SUD were in surprisingly good health. A subpopulation had an overall higher burden of illness with worsened physical and psychiatric functioning. Provision of coordinated care may optimize treatment outcomes for patients based on medical comorbidity burden as well as type of drug abused, although these conclusions should be considered preliminary as they are based on self-reported data.

Potential bias due to outcome-related loss to follow-up in cohort studies on incidence of drug injection: systematic review and meta-analysis

AIMS

A systematic review and meta-analysis were conducted to synthesize results from cohort studies on initiation into drug injection among vulnerable populations, to quantify heterogeneity in the estimated incidence rates of drug injection and to identify potential sources of heterogeneity and bias.

METHODS

MEDLINE, EMBASE, PsycINFO and LILACS were searched for relevant studies published between 1980 and 2012. Investigators independently reviewed studies for inclusion, retrieved information on baseline population characteristics and follow-up features and assessed study quality. Study-specific incidence rates of drug injection were calculated as the number of new injectors divided by the person-years at risk. The I(2) statistic was used to quantify heterogeneity in incidence rates across studies, and random-effects meta-regression models were used to identify determinants of heterogeneity and bias.

RESULTS

Nine cohorts totalling 1843 participants met the inclusion criteria, with individual sample sizes of 70-415 participants and follow-up lengths of 6 months-3.4 years. The incidence of drug injection varied widely, from 2.1 to 24.2 cases per 100 person-years. The strong between-study heterogeneity (I(2)  = 90%, P<0.001) was reduced significantly after accounting for the different follow-up lengths (I(2)  = 17%, P = 0.30), with a 57% (95% confidence interval 46-66%) decrease in the pooled incidence of drug injection per 1-year increase in average follow-up.

CONCLUSIONS

The incidence of drug injection decreases sharply with increasing follow-up length in cohort studies on drug injection initiation. Low retention rates and potential for downward selection bias in cohort studies on drug injection initiation are caused primarily by greater loss to follow-up among individuals at higher risk of starting injection, compared with other participants.

Clinical potential of methylphenidate in the treatment of cocaine addiction: a review of the current evidence

Background

Cocaine use continues to be a public health problem, yet there is no proven effective pharmacotherapy for cocaine dependence. A promising approach to treating cocaine dependence may be agonist-replacement therapy, which is already used effectively in the treatment of opioid and tobacco dependence. The replacement approach for cocaine dependence posits that administration of a long-acting stimulant medication should normalize the neurochemical and behavioral perturbations resulting from chronic cocaine use. One potential medication to be substituted for cocaine is methylphenidate (MPH), as this stimulant possesses pharmacobehavioral properties similar to those of cocaine.

Aim

To provide a qualitative review addressing the rationale for the use of MPH as a cocaine substitute and its clinical potential in the treatment of cocaine dependence.

Methods

We searched MEDLINE for clinical studies using MPH in patients with cocaine abuse/dependence and screened the bibliographies of the articles found for pertinent literature.

Results

MPH, like cocaine, increases synaptic dopamine by inhibiting dopamine reuptake. The discriminative properties, reinforcing potential, and subjective effects of MPH and cocaine are almost identical and, importantly, MPH has been found to substitute for cocaine in animals and human volunteers under laboratory conditions. When taken orally in therapeutic doses, its abuse liability, however, appears low, which is especially true for extended-release MPH preparations. Though there are promising data in the literature, mainly from case reports and open-label studies, the results of randomized controlled trials have been disappointing so far and do not corroborate the use of MPH as a substitute for cocaine dependence in patients without attention deficit hyperactivity disorder.

Conclusion

Clinical studies evaluating MPH substitution for cocaine dependence have provided inconsistent findings. However, the negative findings may be explained by specific study characteristics, among them dosing, duration of treatment, or sample size. This needs to be considered when discussing the potential of MPH as replacement therapy for cocaine dependence. Finally, based on the results, we suggest possible directions for future research.

Mortality Risk Among Heroin Abusers: Clients and Non-clients of Public Treatment Centers for Drug Addiction

In Europe, the prevalence of problematic heroin consumption is declining but, in spite of the constant rise in the number of treated patients, many of them do not turn to a public treatment center (PTC) for their drug addiction. The aim of this study is to study the mortality risk separately for heroin abusers PTC clients and non-PTC clients (i.e., those never treated at a PTC).

METHODS

Cohort study on 959 subjects resident in the metropolitan area of Bologna who went to a health service (i.e., hospital, emergency unit) or to a PTC following problems due to heroin abuse for the first time between 01/01/2004 and 31/12/2009. Standardized mortality ratios (SMRs) were calculated, and regression analysis using the Poisson method was used.

RESULTS

Elevated and statistically significant SMRs were found in both genders, irrespective of the contact facility, being higher for PTC clients. Among non-PTC clients 28% of deaths overall were from AIDS or infectious diseases (6% PTC clients), 17% from opiate overdose (6% PTC clients) and 14% from violent causes (6% PTC clients). Multivariate analysis showed a higher mortality risk for patients who used both heroin and cocaine and for concomitant abuse of benzodiazepines.

CONCLUSIONS

The characteristics of patients never before treated for addiction prompts a reflection on the presence of a hidden group of patients who are hard to reach, who have a high mortality risk and who turn to health care treatment facilities only in the event of an emergency.

The impact of drug use patterns on mortality among polysubstance users in a Canadian setting: a prospective cohort study

Background

Illicit drug use is a well-established risk factor for morbidity and mortality. However, few studies have examined the impact of different drug use patterns on mortality among polysubstance using populations. This study aimed to identify drug-specific patterns of mortality among a cohort of polysubstance using persons who inject drugs (PWIDs).

Methods

PWIDs in Vancouver, Canada were prospectively followed between May 1996 and December 2011. Participants were linked to the provincial vital statistics database to ascertain mortality rates and causes of death. We used multivariate Cox proportional hazards regression to investigate the relationships between drug use patterns (daily alcohol use, heroin injection and non-injection use, cocaine injection, amphetamine injection and non-injection use, crack smoking and speedball injecting) and time to all-cause mortality.

Results

2330 individuals were followed for a median of 61 months (inter-quartile range: 33 – 112). In total, 466 (19.1%) individuals died for an incidence density of 3.1 (95% confidence interval [CI]: 2.8 – 3.4) deaths per 100 person-years. In multivariate analyses, after adjusting for HIV infection and other potential confounders, only daily cocaine injection remained independently associated with all-cause mortality (adjusted hazard ratio [AHR] = 1.36, 95% CI: 1.06 – 1.76).

Conclusions

Although heroin injecting is traditionally viewed as carrying the highest risk of mortality, in this setting, only daily cocaine injecting was associated with all-cause mortality. These findings highlight the urgent need to identify novel treatments and harm reduction strategies for cocaine injectors.

Cocaine use and risk of stroke: a systematic review

BACKGROUND

Both cocaine use and strokes impact public health. Cocaine is a putative cause of strokes, but no systematic review of the scientific evidence has been published.

METHODS

All relevant bibliographic-databases were searched until January 2014 for articles on the epidemiological association between cocaine use and strokes. Search strings were supervised by expert librarians. Three researchers independently reviewed studies for inclusion and data extraction following STROBE recommendations. Quality appraisal included study validity and bias. Both ischemic and hemorrhagic strokes were considered.

RESULTS

Of 996 articles, 9 were selected: 7 case-control studies (CCS) and 2 cross-sectional (CSS) studies. One CCS (aOR=6.1; 95% CI: 3.3-11.8) and one CSS (aOR=2.33; 95% CI: 1.74-3.11) showed an association between cocaine and hemorrhagic strokes. The latter study also found a positive relationship with ischemic stroke (aOR=2.03; 95% CI: 1.48-2.79). Another CCS found the exposure to be associated with stroke without distinguishing between types (aOR=13.9; 95% CI: 2.8-69.4). One forensic CCS found that deaths with cocaine-positive toxicology presented a 14.3-fold (95% CI: 5.6-37) and 4.6-fold (95% CI: 2.5-8.5) increased risk of atherosclerosis compared to opioid-related deaths and hanging-deaths respectively. One CCS did not provide an aOR but found a statistically significant association between cocaine and hemorrhagic stroke. Three CCS and one CSS did not find any relationship between cocaine and strokes. Inadequate control for confounding was not uncommon.

CONCLUSIONS

Epidemiological evidence suggests that cocaine use increases the risk of stroke. Larger, more rigorous observational studies, including cohort approaches, are needed to better quantify this risk, and should consider stroke type, hypertension variation, frequency/length of cocaine use, amphetamines co-use, and other factors.

Gender differences in mortality and risk factors in a 13-year cohort study of street-recruited injecting drug users

BACKGROUND

Injecting drug users (IDUs) are at risk of premature mortality. This study examined gender differences in mortality, risk factors, and causes of death among IDUs.

METHODS

In a 13-year cohort study including 172 street-recruited IDUs from Oslo, Norway in 1997, interview data was merged with the National Cause of Death Registry. Crude mortality rate (CMR) and indirect standardized mortality ratio (SMR) were estimated with 95% confidence intervals (CI). A log-logistic multivariate survival analysis model was estimated for the full sample. For a smaller data set (1.1.1998-31.12.2004) the influence of substitution treatment and prison were assessed using cox regression survival analysis.

RESULTS

Eight females and 37 males died. Acute intoxications were the most common cause of death. Women were more at risk in the short-term, but more protected in the long-term. CMR was 16.0 [95% CI 8.0, 31.9] for women and 26.0 [95% CI 18.0, 35.8]) for men. SMR was 39.4 [95% CI 0.2, 220.8]) for women and 21.3 [95% CI 5.7, 54.1] for men. More women injected heroin (98% vs. 88% [x2 = 3.5, p = 0.063]), used prescription drugs (73% vs. 52% [x2 = 5.6, p = 0.018]) and combined these to inject (45% vs. 26% [x2 = 5.9, p = 0.015]). Mixing prescription drugs in heroin injections, and sex work (only women) were associated with decreased survival time. There were no gender differences in access to substitution treatment, while significantly more men had been in prison (74% vs. 51% [x2 = 7.5, p = 0.006]). The instance of substitution treatment and prison significantly decreased the mortality risk. Prison release increased the risk, but not statistically significantly.

CONCLUSIONS

There were gender differences in mortality and risk factors; sex work and prison were gender specific risk factors. These factors should be investigated further to better design future preventive measures.

Mortality risk for cocaine abusers in relation to heroin use: a follow-up study

Cohort study on 471 subjects resident in the metropolitan area of Bologna who had visited a public treatment center for problems due to the abuse of cocaine from January 1, 1988 to December 31, 2009. Two user typologies were created: cocaine users (no heroin) and heroin and cocaine users. Crude mortality rates and standardized mortality ratios were calculated. We performed a regression analysis using the Poisson method. The study results show a higher mortality risk for those injecting substances and for subjects who took both heroin and cocaine. They appear to have different characteristics from their counterparts who do not use heroin. Future studies should be oriented to this aspect.