http://informahealthcare.com/ada ISSN: 0095-2990 (print), 1097-9891 (electronic) Am J Drug Alcohol Abuse, 2014; 40(2): 137–142 ! 2014 Informa Healthcare USA, Inc. DOI: 10.3109/00952990.2013.861844
ORIGINAL ARTICLE
Association of higher-risk alcohol consumption with injecting paraphernalia sharing behaviours in intravenous drug users Mei Wang, MD1, Jiucheng Shen, MD2, Yuan Deng, MD2, Xianling Liu, MD2, Jianhua Li, MD2, Kim Wolff, PhD3, and Emily Finch, MD4 1
National Addiction Centre, Institute of Psychiatry, King’s College London, UK, 2Yunnan Institute for Drug Abuse, Kunming, China, 3Institute of Pharmaceutical Science, King’s College London, UK, and 4South London & Maudsley NHS Foundation Trust, Addiction Clinical Academic Group, King’s College London Abstract
Keywords
Background: Alcohol use is common among injecting drug users. The coexistence of alcohol consumption and injecting risk behaviour has the potential to increase harms among intravenous drug users (IDUs). Objective: This study aimed to determine whether the level of alcohol use is a risk factor for injecting paraphernalia sharing behaviours. Methods: A total of 637 treatment-seeking IDUs were assessed for injecting paraphernalia sharing behaviours and drinking risk level as defined by the National Institute for Health and Care Excellence (NICE). Multivariate analyses were performed to identify alcohol risk factors associated with injecting paraphernalia sharing behaviours. Results: After adjusting for the effects of ethnicity, employment and drug used, the odds ratio of higher risk drinking for injecting paraphernalia sharing behaviours was 1.92 (95% CI 1.31–2.83). Conclusion: Higher-risk drinking in IDUs is associated with higher rates of injecting paraphernalia sharing behaviours. It is important to take alcohol use into account when evaluating these patients for treatment and designing intervention strategies.
High risk drinking, injection paraphernalia, intravenous drug users, injection sharing behaviours, alcohol use
Alcohol use is common among injecting drug users, and polysubstance use of heroin, cocaine and alcohol is highly prevalent. It is estimated that 52–61% of cocaine abusers are alcohol-dependent (1). The prevalence of heavy alcohol consumption by IDUs ranges from 11–57% (2,3). Heavy alcohol consumption is likely to have an impact on the human immunodeficiency virus (HIV) and hepatitis C virus (HCV) epidemic through risk-taking behaviours. In addition, heavy alcohol use can exacerbate HIV and HCV infection that are prevalent among IDUs (4). A survey undertaken in Sydney reported that heroin-dependent drug users who had co-occurring alcohol problems were significantly more likely than other subjects to have needle-sharing behaviours (5). By the end of 2011 there were more than 100 000 people living with HIV in the United Kingdom (6). Intravenous drug users (IDUs) comprise a vulnerable group in the HIV and acquired immune deficiency syndrome (AIDS) epidemic due to the route of HIV transmission. IDUs are also the primary mode of transmission for HCV infection in the Address correspondence to Mei Wang, MB, BS, MSc, National Addiction Centre, Institute of Psychiatry, 4 Windsor Walk, Denmark Hill, London, SE5 8BB, UK. Tel: +442078480628. Fax: +442078480818. E-mail: [email protected]
Received 30 July 2013 Revised 30 October 2013 Accepted 30 October 2013 Published online 12 February 2014
developed world (7). Therefore they are key populations for interventions to prevent HCV and HIV infections. Injecting paraphernalia sharing behaviours, which include needle, cotton, and water sharing during the injection process, are one of the most efficient routes for HIV and HCV infections. Although interventions such as needle exchange programmes (NEP) have been adopted to reduce the spread of HIV among IDUs, some factors are associated with continued risk behaviours (8). The association between heavy alcohol use and risky sexual behaviour has been well documented (9–12). The coexistence of alcohol use and injecting risk behaviour has the potential to increase harms among IDUs associated with each of these separately. However, evidence linking higher risk alcohol use and drug-related risk behaviours are inconclusive. Some researchers have reported that IDUs who drank alcohol to intoxication in the past 30 days injected drugs with more frequency and were more likely to share injection paraphernalia (10). Studies in samples from needle exchange programs noted that alcohol abuse was associated with needle-sharing behaviours (13,14). These results may be due to the fact that at risk alcohol use is associated with excitement-seeking as well as higher sensation-seeking and risk-taking attitudes (15,16). The brain image in a study by Buddy has showed alcohol activated striatal areas of the brain that are important
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Introduction
History
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components of the reward system and decreased sensitivity in the regions that are involved in reward (17). However, other researchers have found no association (18). The National Treatment Agency for Substance Misuse (NTA) is a special health authority within the UK established in 2001 to implement and monitor government drug policy. The NTA regulates the National Drug Treatment Monitoring System (NDTMS) to collect information from patients who are seeking drug treatment. Service providers collect data on behalf of nine regional NDTMS teams and the data are combined with the Treatment Outcomes Profile (TOP) for subsequent analysis. The South London and Maudsley NHS Foundation Trust (SLaM) provides patient data on behalf of South London NDTMS team. The TOP was established and incorporated into NDTMS in 2007 and consists of 20 items which form data records for the previous 28 days on drug use and associated behaviour that poses a risk to the client’s health, together with the client’s own judgments of their physical and psychological health, their quality of life and criminal behaviour (14). TOP data are reported to NDTMS at the start of the client’s treatment, during reviews which take place during treatment, and at discharge. Data from NDTMS has been used in an in-treatment cohort study to assess how effective of community treatments for heroin and crack cocaine addiction are in England (19). In this study we present results of the association between higher risk alcohol consumption and risky injection behaviours using data from NDTMS. Most studies that have addressed alcohol use and HIV risk behaviours focused on mainly sexual risk behaviours. The co-occurrence of and interaction between the level of alcohol use and injection risk activities and their likely contribution to HIV and HCV infection has received relatively little attention. The present study is an attempt to increase understanding of the association between higher risk alcohol use and injection risk behaviours among IDUs. We believe that the interaction of higher risk alcohol use and injecting risk behaviours requires sustained work to reduce the burden associated with these behaviours and the information will strengthen the programmes already in place to prevent alcohol-related harm and to prevent HIV/AIDS and HCV infection.
Methods Setting SLaM provides inpatient, community and specialist psychiatric services across four London boroughs. The Addiction Clinical Academic Group (CAG) is responsible for inpatient and community treatment addiction services across five London boroughs as well as research activities. Study design and sample Injecting drug users who attended SLaM addiction inpatient or community addiction services for treatment from January 2007 to December 2010 according to NDTMS records were identified. A total of 637 IDUs were included in this study. This study was a case control study; the case group was formed of IDUs that had shared injection-related materials in the last 28 days, and the control group consisted of IDUs
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that had not shared injection-related materials in the past 28 days. Measures In the UK, drinking alcohol is classified by calculation of the number of units of alcohol consumed in a specific period of time, where one unit of alcohol contains 10 ml or 8 grams of ethanol (although in countries outside UK, a ‘‘unit’’ may be defined differently). The alcohol by volume (ABV) is always printed on the label of the container of the liquid, and the label also states how many units of alcohol there are in the container. The same volume of similar types of alcohol can comprise a different number of units depending on the ABV. For example, the ABV of a pint of ordinary strength lager, beer or cider is 3.5% and contains 2 units of alcohol, whereas the ABV of a pint of strong lager, beer or cider is 5% and contains 3 units of alcohol. For the purpose of this study we defined our drinking population as higher-risk drinking according to the National Institute for Health and Care Excellence (NICE) Alcohol Use Disorders Guideline as individuals drinking over 50 (UK) units of alcohol per week (200 units of alcohol in 28 days) for males and over 35 (UK) units of alcohol per week (140 units of alcohol in 28 days) for females as cut-off points (20). Sharing of injection-related materials was assessed by sharing in last 28 days as recorded in the NDTMS form. There were 637 intravenous drug users’ data submitted to the NDTMS by multidisciplinary NHS teams and nongovernmental organizations using anonymised electronic records contained in the SLaM Biomedical Research Centre Clinical Record Interactive Service (CRIS). CRIS is a data resource developed in 2008 to automatically anonymise SLaM electronic clinical notes, enabling clinicians and researchers to retrieve anonymised records. To collect data for TOP, clients are interviewed confidentially by the clinicians and the timeline follow-back technique was used to obtain data for information about drug use. Calendars marked with memorable events were used to help patients recall drug use. This technique has been shown to be psychometrically valid (14), and TOP was shown to have excellent test-retest reliability for drug use (for days of heroin use k ¼ 0.79, heroin abstinence k ¼ 0.88, crack cocaine use k ¼ 0.83, and crack cocaine abstinence k ¼ 0.83). Oral fluid drug toxicology test concordance reached or exceeded the threshold (k ¼ 0.61) for self-reported drug use; and (k ¼ 0.66) for drug toxicology tests. Interview staff were trained and central and regional NDTMS personnel were available to offer help with data collection when needed. Data analysis Initially descriptive statistics were carried out to provide the profile for the study sample. T-tests and Chi-square tests were used to examine associations between demographics, alcohol consumption and measures of injection paraphernalia sharing behaviours. These were followed by logistic regression analyses and a calculation of the odds ratio at 95% confidence interval to further examine the associations. The covariates included age, sex, ethnicity, employment, accommodation, psychiatric comorbidity and drug use. Covariates were identified according to previous studies
Higher-risk alcohol consumption among IDUs
DOI: 10.3109/00952990.2013.861844
Table 1. Basic characteristics and the univariate association with outcome (n ¼ 637). Sharing (Yes) Sharing (No) (n ¼ 214) (n ¼ 423) p Value Total 214 (100) Alcohol used in 28 daysa Non-harmful alcohol use 136 (63.6) Harmful alcohol use 78 (36.4) Age 20.61 6.89 Gender Male 161 (75.2) Female 53 (24.8) Ethnicity White 184 (86.0) Black 19 (8.9) East Asian 1 (0.5) South Asian 4 (1.9) Mixed & others 6 (2.8) Employment Unemployed & seeking work 147 (68.7) Regular employment 7 (3.3) Long-term sickness 28 (13.1) Retired from work 2 (0.9) Others 16 (7.5) Accommodation needed No housing problem 134 (62.6) Housing problem 49 (22.9) Urgent housing problem 30 (14.0) Drug used Heroin 195 (96.5) Cocaine/crack cocaine 1 (0.5) Methadone & other opiates 6 (3.0) Psychiatric co-morbidity No 198 (92.5) Yes 16 (7.5)
423 (100) 320 (75.7) 103 (24.3) 50.011* 21.15 7.88 0.3352 337 (79.7) 86 (20.3) 362 35 0 4 22
(85.6) (8.3) (0.0) (0.9) (5.2)
279 29 21 2 29
(66.0) (6.9) (5.0) (0.2) (6.9)
0.201 50.011* 0.903 0.903 50.011*
0.071 50.011* 0.533 0.891
282 (66.7) 78 (18.4) 62 (14.7)
0.211 0.601
395 (90.8) 8 (1.84) 38 (5.97)
0.203 50.051*
391 (92.4) 32 (7.6)
0.321
a
The cut-off points of higher-risk alcohol use were defined as NICE guidelines of alcohol use disorders of higher risk drinking as individuals consuming over 50 alcohol units per week (200 units of alcohol in 28 days, adult men) or over 35 units per week (140 units of alcohol in 28 days) for female. 1p Value were obtained from Pearson’s Chi-squared test; 2p Value were obtained from Student’s t-test; 3p Value were obtained from Fisher exact test. *p50.05 are statistically significant.
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Table 2. Multivariate analyses for the odds ratio of ever shared status among IDU (n ¼ 637). Variable
ORa
95% CIb
p Value
Ref 1.92
1.31–2.83
50.01*
Ref 0.55 0.93 1.05 0.48
0.40–0.77 0.31–2.77 0.39–2.81 0.27–0.85
50.01* 0.90 0.93 50.01*
Ref 0.43 2.60 1.58 0.87
0.26–0.70 1.84–3.68 0.56–4.41 0.57–1.33
0.07 50.01* 0.53 0.89
Ref 0.25 0.33
0.03–2.04 0.16–0.92
0.20 50.05*
c
Alcohol used in 28 days Non-harmful alcohol use Harmful alcohol use Ethnicity White Black East Asia South Asia Mix & other Employment Unemployed & seeking work Regular employment Long-term sickness Retired from work Other Drug used Heroin Cocaine/crack cocaine Others a
OR, Odds ratio; bCI: Confidence interval; cThe cut-off points of higherrisk alcohol use were defined as NICE guidelines of alcohol use disorder as individuals drinking over 50 units of alcohol per week (200 units in 28 days) for male and over 35 units of alcohol per week (140 units in 28 days) for female. *Statistically significant.
Being white (p50.01) was associated with higher injectionrisk behaviour. Methadone and other opiate users were significantly less likely to share injection paraphernalia (p50.05). Logistic regression was carried out to control confounding factors in the study, including demographics and drug used. IDUs with higher-risk alcohol use were significantly associated with injection paraphernalia sharing when controlled for demographic and other factors previously found to be associated with needle sharing (OR 1.92, 95%, CI: 1.31–2.83).
Discussion on alcohol and drug use and HIV/HCV risk behaviours. No correlation was found between the covariates. All statistical procedures were conducted with Stata 12 (Stata Corp, College Station, TX, USA) and a p value of less than 0.05 was considered to indicate statistical significance.
Results Outcome measure for this study was injecting paraphernalia sharing behaviours. Table 1 provides a general profile of the study sample including basic demographics, type of drugs used, and drug and alcohol use behaviours of the 637 inject drug users, of whom almost 78% were male, 22% being female. The mean age of the sample was 22 years (SD 7.39 years). Most were white British (86%) and 9% were black (p50.001). One third (30%) were classified as having a housing problem or an urgent housing problem. Regarding drug use, 93% of the IDUs reported using heroin. About 28% of the IDUs consumed alcohol at a higher-risk level and 8% were receiving care from mental health services for reasons other substance misuse. Table 2 presents the results of a multivariate analysis of higher-risk drinking against injection risk behaviours.
In this study we used a case-control study design and multivariate analysis to identify associations between levels of alcohol drinking and injection paraphernalia sharing. We found that higher risk consumption of alcohol over 28 days was associated with greater injection paraphernalia sharing behaviour among IDUs. The odds ratio of patients using more than 200 units of alcohol in 28 days and sharing injecting paraphernalia was 1.92 times (p50.001) that for patients with lower alcohol consumption. Our findings were in agreement with some earlier studies which showed heavier drinking and alcohol use were frequency associated with high risk behaviour independent of other confounding variables (10,11,15,18,21,22). A study carried out by Stein et al. (10) among drug users participated in needle exchange programme demonstrated that hazardous drinking was significantly associated with higher rates of drug and sex-related risk behaviours. Other studies also showed that at-risk alcohol consumption plays an important role in needle sharing among intravenous drug users (10,11,18,22,23). At-risk alcohol drinking by injecting drug users at the time of needle use may lead to poor judgment. This could be a direct effect of alcohol intoxication on risky
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injection behaviour. The relationship between alcohol use and risky sexual behaviour can be explained by their common association with excitement seeking. Similar pathways may also function in the association of alcohol use and intravenous drug use risk behaviour (15). Alcohol use may also confer a greater risk for risky intravenous drug use through the following mechanism. First of all, research has shown that alcohol is a gateway drug, consumption of alcohol can lead to more serious drug addiction. Alcohol users will revert to their old drug use activities by using the drug itself or in combination with other drugs (24). Secondly, alcohol use can affect the frontal lobe of the brain, and increasing levels of alcohol dependence can lead to decreasing level of judgment and self-control, as well as behavioural disinhibition that occurs in the context of acute intoxication (25). In addition, there are well-established links between impulsivity and alcohol use, that is, heavy alcohol consumption can trigger impulsive behaviour (17,26). Studies of the development of the dependence process also suggest that increasing levels of alcohol dependence can induce negative effect and weaken self-regulation, hence decreasing levels of self-control (27). On the other hand, studies of high risk behaviour and alcohol abuse show that high risk behaviour is associated with higher sensation-seeking and risk-taking attitudes. Another possible suggestion is that social and environmental factors act as mediating factors (e.g. bidirectional link) between alcohol use and sexual or injection risk behaviour (16). However, our analysis is inconsistent with other previous findings. For example, Rees et al. (18) found that alcohol consumption is associated with sexual risk behaviour but not with drug use-related risk behaviours. The possible explanations for the discrepant findings between the two studies are not clear. They may be related to the nature of the different populations of drug users studied. In Rees et al.’s study the population was recruited from an inpatient detoxification programme. The population in their study were general drug users, while the cohort of our study was formed of injecting drug users, who have more chance to share injecting-related materials. Another reason could be the sample size included. Rees et al.’s study contains only 105 IDUs, and since these were divided into three ADV groups, the sample size in each group could be too small to detect a significant effect. The difference in findings may also be due to the time period over which the risk behaviour was assessed. Our study was assessing sharing injecting paraphernalia behaviour in the past 28 days, while Rees et al.’s study was assessing RAB risk in the past 6 months; therefore, it is possible that there was recall bias in their study. In addition, the measures used to classify alcohol use were different in the two studies. Alcohol consumption was measured in Rees et al.’s study as selfreported mean daily alcohol consumption (average daily volume, ADV) over the past 30 days. In this study we defined our drinking population according to the NICE Alcohol Use Disorders Guideline. The different measure might lead to different findings. Another interesting finding in this study was that the percentage of psychiatric co-morbidity was only 7%. This is much lower than other studies (28,29). The possible explanation for this apparent inconsistent finding is that psychiatric co-morbidity (dual diagnosis) was defined in NDTMS dataset as ‘‘is the client currently receiving care
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from mental health services for reasons other than substance misuse?’’ Under this definition, only severe patients actually receiving treatment were classified under this group, therefore only 7% of the sample in this study had psychiatric co-morbidity. Intravenous drug users form the primary group of people at risk for HIV/HCV infections (18). Comorbid alcohol use is common among drug users (30). The rate of alcohol abuse is higher among IDUs than among the general population (31). Our analysis showed that 28% of injecting drug users consumed alcohol at higher risk level. The level of drinking recorded in this study is consistent with previous reports of alcohol consumption in IDUs (23,32). This finding indicated that interventions to reduce alcohol consumption in the IDU population are urgently needed. Some studies have shown that reducing alcohol consumption is possible in IDUs, however is less successful in reducing injection-risk behaviours (13,33,34). Alcohol reducing measures might be paired with other interventions, such as needle exchange and injecting equipment and condom distribution, to reduce injecting risk and sexual risk behaviours and future morbidities in this population. The goal of reducing alcohol consumption in the IDU population is challenging, especially with high rates of homelessness, unemployment and psychiatric co-morbidity among these people. Regardless of the true nature of the relationship between alcohol use and injection risk behaviour, our finding provides important information for understanding the persistence of HIV risk behaviours among IDUs. Targeting alcohol use disorders in drug treatment and prevention programmes may reduce risk behaviours among drug injectors. However, lack of information on effective concurrent treatment of drug and alcohol use limits health professionals to provide comprehensive treatment for these patients (35). Further research is recommended to fill this gap of information in the drug treatment field.
Limitations and conclusion We recognized that the findings of this study have several limitations. First of all, our results are subject to the limitations of observational studies that prevent us from inferring a causal relationship between alcohol use and the injecting paraphernalia sharing behaviours. For example, a recent prospective cohort study showed that risky drug and sexual behaviours also affect patients’ drinking patterns, suggesting a bidirectional link between these two factors (36). Thus, whether alcohol use precedes or is subsequent to injection paraphernalia sharing cannot be told from this study and remains to be determined (19). Secondly, our measure of alcohol consumption does not allow us to examine a doseresponse relationship between alcohol use and injection risk behaviours. Furthermore, we did not control for drug use severity in this study. This could be an important limitation of this study as the heavy alcohol users may reflect a more severe subgroup containing heavier users in general. People with more days of drug use are more likely to engage in needle-sharing behaviours. The information may strengthen the analysis. However, we controlled drug use (heroin, cocaine/crack cocaine, methadone and other opiates) in the
DOI: 10.3109/00952990.2013.861844
logistic regression as confounding factors. Also, as the sample included in this study was IDUs, injecting drug users are more severe drug users than other drug users to start with. Another limitation was that the sample size of cocaine and other opioid users in this study was small, which may decrease our power to detect the association between types of drug and injecting paraphernalia sharing behaviours. In addition, our cohort consisted of patients attending treatment in SLaM. Therefore, patients selected in this study were geographically limited and the results may not be generalizable to the population of IDUs in the UK in general. However, SLaM is the main provider of mental health services in South London, and the broad spectrum of living areas of South London makes the population overall comparable to those of London in terms of age, gender and socioeconomic status (37). Lastly, the exposure and outcome measures in this study were collected by clinic staff participating in the treatment for the patients, rather than by independent researchers. However, the TOP showed excellent reliability between clinic staffs (14). HIV and HCV status was not assessed in this study, and we are unable to report the impact of infection on risk behaviours. The strength of this study is the use of a particular high-risk population. In conclusion, our data indicate that alcohol use and unsafe drug injection are associated. Thus, it is possible that intravenous drug use is one pathway linking heavy alcohol consumption to HIV transmission. Targeting alcohol use disorders in drug treatment and prevention programmes can help understanding the persistence of HIV risk transmission among IDUs, treating these patients and designing intervention strategies. Other structured interventions to reduce alcohol consumption such as regulating the availability, price and advertising of alcohol are also recommended. Future studies should be carried out to further determine if injection risk days are also alcohol use days for active injection drug users.
Acknowledgements This study was supported by Addiction Department of Institute of Psychiatry, King’s College London. Ethical approval SLaM Biomedical Research Centre Clinical Record Interactive Service (CRIS) received ethical approval for secondary analysis by Oxfordshire REC in 2008 (reference number 08/H0606/71).
Declaration of interest The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
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ORIGINAL ARTICLE
Association of higher-risk alcohol consumption with injecting paraphernalia sharing behaviours in intravenous drug users Mei Wang, MD1, Jiucheng Shen, MD2, Yuan Deng, MD2, Xianling Liu, MD2, Jianhua Li, MD2, Kim Wolff, PhD3, and Emily Finch, MD4 1
National Addiction Centre, Institute of Psychiatry, King’s College London, UK, 2Yunnan Institute for Drug Abuse, Kunming, China, 3Institute of Pharmaceutical Science, King’s College London, UK, and 4South London & Maudsley NHS Foundation Trust, Addiction Clinical Academic Group, King’s College London Abstract
Keywords
Background: Alcohol use is common among injecting drug users. The coexistence of alcohol consumption and injecting risk behaviour has the potential to increase harms among intravenous drug users (IDUs). Objective: This study aimed to determine whether the level of alcohol use is a risk factor for injecting paraphernalia sharing behaviours. Methods: A total of 637 treatment-seeking IDUs were assessed for injecting paraphernalia sharing behaviours and drinking risk level as defined by the National Institute for Health and Care Excellence (NICE). Multivariate analyses were performed to identify alcohol risk factors associated with injecting paraphernalia sharing behaviours. Results: After adjusting for the effects of ethnicity, employment and drug used, the odds ratio of higher risk drinking for injecting paraphernalia sharing behaviours was 1.92 (95% CI 1.31–2.83). Conclusion: Higher-risk drinking in IDUs is associated with higher rates of injecting paraphernalia sharing behaviours. It is important to take alcohol use into account when evaluating these patients for treatment and designing intervention strategies.
High risk drinking, injection paraphernalia, intravenous drug users, injection sharing behaviours, alcohol use
Alcohol use is common among injecting drug users, and polysubstance use of heroin, cocaine and alcohol is highly prevalent. It is estimated that 52–61% of cocaine abusers are alcohol-dependent (1). The prevalence of heavy alcohol consumption by IDUs ranges from 11–57% (2,3). Heavy alcohol consumption is likely to have an impact on the human immunodeficiency virus (HIV) and hepatitis C virus (HCV) epidemic through risk-taking behaviours. In addition, heavy alcohol use can exacerbate HIV and HCV infection that are prevalent among IDUs (4). A survey undertaken in Sydney reported that heroin-dependent drug users who had co-occurring alcohol problems were significantly more likely than other subjects to have needle-sharing behaviours (5). By the end of 2011 there were more than 100 000 people living with HIV in the United Kingdom (6). Intravenous drug users (IDUs) comprise a vulnerable group in the HIV and acquired immune deficiency syndrome (AIDS) epidemic due to the route of HIV transmission. IDUs are also the primary mode of transmission for HCV infection in the Address correspondence to Mei Wang, MB, BS, MSc, National Addiction Centre, Institute of Psychiatry, 4 Windsor Walk, Denmark Hill, London, SE5 8BB, UK. Tel: +442078480628. Fax: +442078480818. E-mail: [email protected]
Received 30 July 2013 Revised 30 October 2013 Accepted 30 October 2013 Published online 12 February 2014
developed world (7). Therefore they are key populations for interventions to prevent HCV and HIV infections. Injecting paraphernalia sharing behaviours, which include needle, cotton, and water sharing during the injection process, are one of the most efficient routes for HIV and HCV infections. Although interventions such as needle exchange programmes (NEP) have been adopted to reduce the spread of HIV among IDUs, some factors are associated with continued risk behaviours (8). The association between heavy alcohol use and risky sexual behaviour has been well documented (9–12). The coexistence of alcohol use and injecting risk behaviour has the potential to increase harms among IDUs associated with each of these separately. However, evidence linking higher risk alcohol use and drug-related risk behaviours are inconclusive. Some researchers have reported that IDUs who drank alcohol to intoxication in the past 30 days injected drugs with more frequency and were more likely to share injection paraphernalia (10). Studies in samples from needle exchange programs noted that alcohol abuse was associated with needle-sharing behaviours (13,14). These results may be due to the fact that at risk alcohol use is associated with excitement-seeking as well as higher sensation-seeking and risk-taking attitudes (15,16). The brain image in a study by Buddy has showed alcohol activated striatal areas of the brain that are important
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Introduction
History
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components of the reward system and decreased sensitivity in the regions that are involved in reward (17). However, other researchers have found no association (18). The National Treatment Agency for Substance Misuse (NTA) is a special health authority within the UK established in 2001 to implement and monitor government drug policy. The NTA regulates the National Drug Treatment Monitoring System (NDTMS) to collect information from patients who are seeking drug treatment. Service providers collect data on behalf of nine regional NDTMS teams and the data are combined with the Treatment Outcomes Profile (TOP) for subsequent analysis. The South London and Maudsley NHS Foundation Trust (SLaM) provides patient data on behalf of South London NDTMS team. The TOP was established and incorporated into NDTMS in 2007 and consists of 20 items which form data records for the previous 28 days on drug use and associated behaviour that poses a risk to the client’s health, together with the client’s own judgments of their physical and psychological health, their quality of life and criminal behaviour (14). TOP data are reported to NDTMS at the start of the client’s treatment, during reviews which take place during treatment, and at discharge. Data from NDTMS has been used in an in-treatment cohort study to assess how effective of community treatments for heroin and crack cocaine addiction are in England (19). In this study we present results of the association between higher risk alcohol consumption and risky injection behaviours using data from NDTMS. Most studies that have addressed alcohol use and HIV risk behaviours focused on mainly sexual risk behaviours. The co-occurrence of and interaction between the level of alcohol use and injection risk activities and their likely contribution to HIV and HCV infection has received relatively little attention. The present study is an attempt to increase understanding of the association between higher risk alcohol use and injection risk behaviours among IDUs. We believe that the interaction of higher risk alcohol use and injecting risk behaviours requires sustained work to reduce the burden associated with these behaviours and the information will strengthen the programmes already in place to prevent alcohol-related harm and to prevent HIV/AIDS and HCV infection.
Methods Setting SLaM provides inpatient, community and specialist psychiatric services across four London boroughs. The Addiction Clinical Academic Group (CAG) is responsible for inpatient and community treatment addiction services across five London boroughs as well as research activities. Study design and sample Injecting drug users who attended SLaM addiction inpatient or community addiction services for treatment from January 2007 to December 2010 according to NDTMS records were identified. A total of 637 IDUs were included in this study. This study was a case control study; the case group was formed of IDUs that had shared injection-related materials in the last 28 days, and the control group consisted of IDUs
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that had not shared injection-related materials in the past 28 days. Measures In the UK, drinking alcohol is classified by calculation of the number of units of alcohol consumed in a specific period of time, where one unit of alcohol contains 10 ml or 8 grams of ethanol (although in countries outside UK, a ‘‘unit’’ may be defined differently). The alcohol by volume (ABV) is always printed on the label of the container of the liquid, and the label also states how many units of alcohol there are in the container. The same volume of similar types of alcohol can comprise a different number of units depending on the ABV. For example, the ABV of a pint of ordinary strength lager, beer or cider is 3.5% and contains 2 units of alcohol, whereas the ABV of a pint of strong lager, beer or cider is 5% and contains 3 units of alcohol. For the purpose of this study we defined our drinking population as higher-risk drinking according to the National Institute for Health and Care Excellence (NICE) Alcohol Use Disorders Guideline as individuals drinking over 50 (UK) units of alcohol per week (200 units of alcohol in 28 days) for males and over 35 (UK) units of alcohol per week (140 units of alcohol in 28 days) for females as cut-off points (20). Sharing of injection-related materials was assessed by sharing in last 28 days as recorded in the NDTMS form. There were 637 intravenous drug users’ data submitted to the NDTMS by multidisciplinary NHS teams and nongovernmental organizations using anonymised electronic records contained in the SLaM Biomedical Research Centre Clinical Record Interactive Service (CRIS). CRIS is a data resource developed in 2008 to automatically anonymise SLaM electronic clinical notes, enabling clinicians and researchers to retrieve anonymised records. To collect data for TOP, clients are interviewed confidentially by the clinicians and the timeline follow-back technique was used to obtain data for information about drug use. Calendars marked with memorable events were used to help patients recall drug use. This technique has been shown to be psychometrically valid (14), and TOP was shown to have excellent test-retest reliability for drug use (for days of heroin use k ¼ 0.79, heroin abstinence k ¼ 0.88, crack cocaine use k ¼ 0.83, and crack cocaine abstinence k ¼ 0.83). Oral fluid drug toxicology test concordance reached or exceeded the threshold (k ¼ 0.61) for self-reported drug use; and (k ¼ 0.66) for drug toxicology tests. Interview staff were trained and central and regional NDTMS personnel were available to offer help with data collection when needed. Data analysis Initially descriptive statistics were carried out to provide the profile for the study sample. T-tests and Chi-square tests were used to examine associations between demographics, alcohol consumption and measures of injection paraphernalia sharing behaviours. These were followed by logistic regression analyses and a calculation of the odds ratio at 95% confidence interval to further examine the associations. The covariates included age, sex, ethnicity, employment, accommodation, psychiatric comorbidity and drug use. Covariates were identified according to previous studies
Higher-risk alcohol consumption among IDUs
DOI: 10.3109/00952990.2013.861844
Table 1. Basic characteristics and the univariate association with outcome (n ¼ 637). Sharing (Yes) Sharing (No) (n ¼ 214) (n ¼ 423) p Value Total 214 (100) Alcohol used in 28 daysa Non-harmful alcohol use 136 (63.6) Harmful alcohol use 78 (36.4) Age 20.61 6.89 Gender Male 161 (75.2) Female 53 (24.8) Ethnicity White 184 (86.0) Black 19 (8.9) East Asian 1 (0.5) South Asian 4 (1.9) Mixed & others 6 (2.8) Employment Unemployed & seeking work 147 (68.7) Regular employment 7 (3.3) Long-term sickness 28 (13.1) Retired from work 2 (0.9) Others 16 (7.5) Accommodation needed No housing problem 134 (62.6) Housing problem 49 (22.9) Urgent housing problem 30 (14.0) Drug used Heroin 195 (96.5) Cocaine/crack cocaine 1 (0.5) Methadone & other opiates 6 (3.0) Psychiatric co-morbidity No 198 (92.5) Yes 16 (7.5)
423 (100) 320 (75.7) 103 (24.3) 50.011* 21.15 7.88 0.3352 337 (79.7) 86 (20.3) 362 35 0 4 22
(85.6) (8.3) (0.0) (0.9) (5.2)
279 29 21 2 29
(66.0) (6.9) (5.0) (0.2) (6.9)
0.201 50.011* 0.903 0.903 50.011*
0.071 50.011* 0.533 0.891
282 (66.7) 78 (18.4) 62 (14.7)
0.211 0.601
395 (90.8) 8 (1.84) 38 (5.97)
0.203 50.051*
391 (92.4) 32 (7.6)
0.321
a
The cut-off points of higher-risk alcohol use were defined as NICE guidelines of alcohol use disorders of higher risk drinking as individuals consuming over 50 alcohol units per week (200 units of alcohol in 28 days, adult men) or over 35 units per week (140 units of alcohol in 28 days) for female. 1p Value were obtained from Pearson’s Chi-squared test; 2p Value were obtained from Student’s t-test; 3p Value were obtained from Fisher exact test. *p50.05 are statistically significant.
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Table 2. Multivariate analyses for the odds ratio of ever shared status among IDU (n ¼ 637). Variable
ORa
95% CIb
p Value
Ref 1.92
1.31–2.83
50.01*
Ref 0.55 0.93 1.05 0.48
0.40–0.77 0.31–2.77 0.39–2.81 0.27–0.85
50.01* 0.90 0.93 50.01*
Ref 0.43 2.60 1.58 0.87
0.26–0.70 1.84–3.68 0.56–4.41 0.57–1.33
0.07 50.01* 0.53 0.89
Ref 0.25 0.33
0.03–2.04 0.16–0.92
0.20 50.05*
c
Alcohol used in 28 days Non-harmful alcohol use Harmful alcohol use Ethnicity White Black East Asia South Asia Mix & other Employment Unemployed & seeking work Regular employment Long-term sickness Retired from work Other Drug used Heroin Cocaine/crack cocaine Others a
OR, Odds ratio; bCI: Confidence interval; cThe cut-off points of higherrisk alcohol use were defined as NICE guidelines of alcohol use disorder as individuals drinking over 50 units of alcohol per week (200 units in 28 days) for male and over 35 units of alcohol per week (140 units in 28 days) for female. *Statistically significant.
Being white (p50.01) was associated with higher injectionrisk behaviour. Methadone and other opiate users were significantly less likely to share injection paraphernalia (p50.05). Logistic regression was carried out to control confounding factors in the study, including demographics and drug used. IDUs with higher-risk alcohol use were significantly associated with injection paraphernalia sharing when controlled for demographic and other factors previously found to be associated with needle sharing (OR 1.92, 95%, CI: 1.31–2.83).
Discussion on alcohol and drug use and HIV/HCV risk behaviours. No correlation was found between the covariates. All statistical procedures were conducted with Stata 12 (Stata Corp, College Station, TX, USA) and a p value of less than 0.05 was considered to indicate statistical significance.
Results Outcome measure for this study was injecting paraphernalia sharing behaviours. Table 1 provides a general profile of the study sample including basic demographics, type of drugs used, and drug and alcohol use behaviours of the 637 inject drug users, of whom almost 78% were male, 22% being female. The mean age of the sample was 22 years (SD 7.39 years). Most were white British (86%) and 9% were black (p50.001). One third (30%) were classified as having a housing problem or an urgent housing problem. Regarding drug use, 93% of the IDUs reported using heroin. About 28% of the IDUs consumed alcohol at a higher-risk level and 8% were receiving care from mental health services for reasons other substance misuse. Table 2 presents the results of a multivariate analysis of higher-risk drinking against injection risk behaviours.
In this study we used a case-control study design and multivariate analysis to identify associations between levels of alcohol drinking and injection paraphernalia sharing. We found that higher risk consumption of alcohol over 28 days was associated with greater injection paraphernalia sharing behaviour among IDUs. The odds ratio of patients using more than 200 units of alcohol in 28 days and sharing injecting paraphernalia was 1.92 times (p50.001) that for patients with lower alcohol consumption. Our findings were in agreement with some earlier studies which showed heavier drinking and alcohol use were frequency associated with high risk behaviour independent of other confounding variables (10,11,15,18,21,22). A study carried out by Stein et al. (10) among drug users participated in needle exchange programme demonstrated that hazardous drinking was significantly associated with higher rates of drug and sex-related risk behaviours. Other studies also showed that at-risk alcohol consumption plays an important role in needle sharing among intravenous drug users (10,11,18,22,23). At-risk alcohol drinking by injecting drug users at the time of needle use may lead to poor judgment. This could be a direct effect of alcohol intoxication on risky
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injection behaviour. The relationship between alcohol use and risky sexual behaviour can be explained by their common association with excitement seeking. Similar pathways may also function in the association of alcohol use and intravenous drug use risk behaviour (15). Alcohol use may also confer a greater risk for risky intravenous drug use through the following mechanism. First of all, research has shown that alcohol is a gateway drug, consumption of alcohol can lead to more serious drug addiction. Alcohol users will revert to their old drug use activities by using the drug itself or in combination with other drugs (24). Secondly, alcohol use can affect the frontal lobe of the brain, and increasing levels of alcohol dependence can lead to decreasing level of judgment and self-control, as well as behavioural disinhibition that occurs in the context of acute intoxication (25). In addition, there are well-established links between impulsivity and alcohol use, that is, heavy alcohol consumption can trigger impulsive behaviour (17,26). Studies of the development of the dependence process also suggest that increasing levels of alcohol dependence can induce negative effect and weaken self-regulation, hence decreasing levels of self-control (27). On the other hand, studies of high risk behaviour and alcohol abuse show that high risk behaviour is associated with higher sensation-seeking and risk-taking attitudes. Another possible suggestion is that social and environmental factors act as mediating factors (e.g. bidirectional link) between alcohol use and sexual or injection risk behaviour (16). However, our analysis is inconsistent with other previous findings. For example, Rees et al. (18) found that alcohol consumption is associated with sexual risk behaviour but not with drug use-related risk behaviours. The possible explanations for the discrepant findings between the two studies are not clear. They may be related to the nature of the different populations of drug users studied. In Rees et al.’s study the population was recruited from an inpatient detoxification programme. The population in their study were general drug users, while the cohort of our study was formed of injecting drug users, who have more chance to share injecting-related materials. Another reason could be the sample size included. Rees et al.’s study contains only 105 IDUs, and since these were divided into three ADV groups, the sample size in each group could be too small to detect a significant effect. The difference in findings may also be due to the time period over which the risk behaviour was assessed. Our study was assessing sharing injecting paraphernalia behaviour in the past 28 days, while Rees et al.’s study was assessing RAB risk in the past 6 months; therefore, it is possible that there was recall bias in their study. In addition, the measures used to classify alcohol use were different in the two studies. Alcohol consumption was measured in Rees et al.’s study as selfreported mean daily alcohol consumption (average daily volume, ADV) over the past 30 days. In this study we defined our drinking population according to the NICE Alcohol Use Disorders Guideline. The different measure might lead to different findings. Another interesting finding in this study was that the percentage of psychiatric co-morbidity was only 7%. This is much lower than other studies (28,29). The possible explanation for this apparent inconsistent finding is that psychiatric co-morbidity (dual diagnosis) was defined in NDTMS dataset as ‘‘is the client currently receiving care
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from mental health services for reasons other than substance misuse?’’ Under this definition, only severe patients actually receiving treatment were classified under this group, therefore only 7% of the sample in this study had psychiatric co-morbidity. Intravenous drug users form the primary group of people at risk for HIV/HCV infections (18). Comorbid alcohol use is common among drug users (30). The rate of alcohol abuse is higher among IDUs than among the general population (31). Our analysis showed that 28% of injecting drug users consumed alcohol at higher risk level. The level of drinking recorded in this study is consistent with previous reports of alcohol consumption in IDUs (23,32). This finding indicated that interventions to reduce alcohol consumption in the IDU population are urgently needed. Some studies have shown that reducing alcohol consumption is possible in IDUs, however is less successful in reducing injection-risk behaviours (13,33,34). Alcohol reducing measures might be paired with other interventions, such as needle exchange and injecting equipment and condom distribution, to reduce injecting risk and sexual risk behaviours and future morbidities in this population. The goal of reducing alcohol consumption in the IDU population is challenging, especially with high rates of homelessness, unemployment and psychiatric co-morbidity among these people. Regardless of the true nature of the relationship between alcohol use and injection risk behaviour, our finding provides important information for understanding the persistence of HIV risk behaviours among IDUs. Targeting alcohol use disorders in drug treatment and prevention programmes may reduce risk behaviours among drug injectors. However, lack of information on effective concurrent treatment of drug and alcohol use limits health professionals to provide comprehensive treatment for these patients (35). Further research is recommended to fill this gap of information in the drug treatment field.
Limitations and conclusion We recognized that the findings of this study have several limitations. First of all, our results are subject to the limitations of observational studies that prevent us from inferring a causal relationship between alcohol use and the injecting paraphernalia sharing behaviours. For example, a recent prospective cohort study showed that risky drug and sexual behaviours also affect patients’ drinking patterns, suggesting a bidirectional link between these two factors (36). Thus, whether alcohol use precedes or is subsequent to injection paraphernalia sharing cannot be told from this study and remains to be determined (19). Secondly, our measure of alcohol consumption does not allow us to examine a doseresponse relationship between alcohol use and injection risk behaviours. Furthermore, we did not control for drug use severity in this study. This could be an important limitation of this study as the heavy alcohol users may reflect a more severe subgroup containing heavier users in general. People with more days of drug use are more likely to engage in needle-sharing behaviours. The information may strengthen the analysis. However, we controlled drug use (heroin, cocaine/crack cocaine, methadone and other opiates) in the
DOI: 10.3109/00952990.2013.861844
logistic regression as confounding factors. Also, as the sample included in this study was IDUs, injecting drug users are more severe drug users than other drug users to start with. Another limitation was that the sample size of cocaine and other opioid users in this study was small, which may decrease our power to detect the association between types of drug and injecting paraphernalia sharing behaviours. In addition, our cohort consisted of patients attending treatment in SLaM. Therefore, patients selected in this study were geographically limited and the results may not be generalizable to the population of IDUs in the UK in general. However, SLaM is the main provider of mental health services in South London, and the broad spectrum of living areas of South London makes the population overall comparable to those of London in terms of age, gender and socioeconomic status (37). Lastly, the exposure and outcome measures in this study were collected by clinic staff participating in the treatment for the patients, rather than by independent researchers. However, the TOP showed excellent reliability between clinic staffs (14). HIV and HCV status was not assessed in this study, and we are unable to report the impact of infection on risk behaviours. The strength of this study is the use of a particular high-risk population. In conclusion, our data indicate that alcohol use and unsafe drug injection are associated. Thus, it is possible that intravenous drug use is one pathway linking heavy alcohol consumption to HIV transmission. Targeting alcohol use disorders in drug treatment and prevention programmes can help understanding the persistence of HIV risk transmission among IDUs, treating these patients and designing intervention strategies. Other structured interventions to reduce alcohol consumption such as regulating the availability, price and advertising of alcohol are also recommended. Future studies should be carried out to further determine if injection risk days are also alcohol use days for active injection drug users.
Acknowledgements This study was supported by Addiction Department of Institute of Psychiatry, King’s College London. Ethical approval SLaM Biomedical Research Centre Clinical Record Interactive Service (CRIS) received ethical approval for secondary analysis by Oxfordshire REC in 2008 (reference number 08/H0606/71).
Declaration of interest The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
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