An international comparative study of HIV prevalence and risk behaviour among drug injectors in 13 cities

Sections

ABSTRACT
Introduction
Methodology
Results

Details

Author: WHO COLLABORATIVE STUDY GROUP
Pages: 19 to 46
Creation Date: 1993/01/01

An international comparative study of HIV prevalence and risk behaviour among drug injectors in 13 cities

WHO COLLABORATIVE STUDY GROUP *
Programme on Substance Abuse, World Health Organization, Geneva, Switzerland

ABSTRACT

Although reported rates of human immunodeficiency virus OHV) infection and related risk behaviours among drug injectors vary considerably throughout the world, ' and comparison of findings is often hampered by methodological variability among centres. In 1989 the World Health Organization initiated a comparative study of current drug- injecting behaviour and HIV infection using a standardized methodology. Centres were asked to recruit at least half of their samples outside drug treatment settings in order to achieve as representative a group of injectors as possible. Respondents were interviewed using a questionnaire designed by I an international working group, and they were asked to provide blood and/or saliva specimens for voluntary testing. Data from 13 centres (Athens, Bangkok, Berlin, Glasgow, London, Madrid, Naples, New York, Rome, Rio de Janeiro, Santos, Sydney and Toronto) are reported here. A total of 6,390 injectors were recruited to the study from October 1989 to March 1992, with sample sizes ranging from 85 at Santos (Brazil) to 1,300 in New York. Weekly or daily sharing of injecting equipment was reported by less than a quarter of injectors in all centres. A high proportion of those sharing made some effort to clean equipment before use, although not always by efficient methods. In all centres, the majority of respondents were sexually active; however, rates of unprotected sexual intercourse were high, particularly between regular sexual partners. The overall HIV prevalence rate was 22 per cent, ranging from 0 per cent in Athens to 60 per cent in Santos. Caution should be exercised in postulating a link between HIV prevalence and current risk behaviour, particularly since injectors appear to behave in similar ways across a diverse range of study locations. This is the first report on an international collaborative study for which a large number of injectors were successfully recruited from a variety of settings. The wealth of data now available provides a greater understanding of the social epidemiology of drug injecting, which is essential for the implementation and evaluation of campaigns and interventions designed to limit the spread of HIV infection.

*Athens - Meni Malliori, C. Stefanis; Bangkok - Kachit Choopanya, Suphak Vanichseni, Suwanee Raktham, Wandee Sonchai; Berlin - Dieter Klieber, Anand Pant, Wolfgang Heckmann; Glasgow - Martin Frischer, David Goldberg, Stephen Green, Neil McKeganey; London - Martin Donoghue, Gillian Hunter, Adam Crosier, Gerry Stimson; Madrid - Victoria Zunzunegui Pastor, Angeles Rodrigues-Arenas, Juan Carlos Romero Bellido; Naples (together with Cagliari, Milan and Verona) - G. Rezza, S. Salmaso, A. Anemona; New York - Don Des Jarlais, Samuel Friedman, Jo Sotheran, John Wenston; Rio de Janeiro - Elson Lima, Paulo Telles, Francisco Bastos, Maria Thereza Aquino; Rome - Damiano Abeni, Giovanna Brancato, Carlo Perucci, Francesca Zampieiri; Santos - Fabio Mesquita, Regina Bueno, Giselda Paes, Andrew Moss; Sydney - Alex Wodak, Aaron Stowe, Michael Ross; Toronto - Peggy Millson, Ted Myers, James Rankin, Carol Major; WHO (Geneva) - Manuel Carballo, Marcus Grant.

Introduction

In the early to middle 1980s, it became apparent that the sharing of injecting equipment by drug users was a highly efficient means of HIV transmission. With studies of drug injectors in Western European and North American centres recording high HIV prevalence rates [ 1] , there was particular concern that the group, comprising young heterosexually active men and women, would constitute a potential conduit for the sexual transmission of HIV to the wider community [ 2] .

The importance of these early findings was appreciated by the World Health Organization (WHO), which recognized the need for centres worldwide to increase their understanding of HIV-related risk behaviours. Only then could effective interventions, designed to reduce the transmission of HIV among drug injectors, be initiated with confidence. Prior to the advent of HIV infection, information on injecting drug use was extremely limited in most parts of the world. Even in the United States of America and Europe, where research was more advanced, basic epidemiological information was scarce, and behavioural data were limited to small samples of injectors [3, 4] recruited mainly in treatment settings. In October 1987, the then Chief of the Social and Behavioural Branch of the World Health Organization's Global Programme on AIDS, Manuel Carballo, brought together researchers from 13 centres (Athens, Bangkok, Berlin, Glasgow, London, Madrid, Naples, New York, Rio de Janeiro, Rome, Santos, Sydney and Toronto) to address these issues.

The WHO collaborative group identified two principal objectives. The first was to quantify types of high-risk drug injecting and sexual behaviour among drug injectors and to measure any changes in behaviour over time. The second was to determine the prevalence of HIV among such populations and to measure any changes in prevalence over time. By mid-1989 the researchers had developed a standardized study methodology, a core interview schedule and an interview instruction manual. Most centres, having obtained funding from national agencies or from WHO, commenced the first phase of the study between November 1989 and May 1991. It was anticipated that greater understanding of wider issues, such as the cultural, legal, political and social environments in which injecting-related behaviours occur (including the presence or absence of intervention programmes), would be achieved through parallel investigations.

The data presented here, from the first phase of the project, should therefore be considered as "dependent variables" influenced by wide- ranging factors. The aim of the present paper is simply to identify differences and similarities between the centres, rather than the more ambitious objective of explaining such variations. Hitherto, there have been no comparative data of such detail; the present study thus provides an opportunity to address basic epidemiological and behavioural issues which have been the subject of much speculation.

The study of large numbers of drug injectors may also inform the WHO wider surveillance programme with regard to estimates of the number of HIV-infected injectors throughout the world, and thus of the potential for transmission to non-injectors. WHO estimates that in Australasia, North America and Western Europe, 1.5 million adult HIV infections may have occurred by early 1991, and that while there are "large numbers of uninfected drug users in many areas ... explosive spread can occur if sharing of injecting equipment continues' [ 5] . Of the 68,352 cases of AIDS among adults reported by 32 European countries to WHO by June 1992, 25,402 (37 per cent) were drug injectors [61, compared to 1,292 out of 6,121 (21 per cent) by June 1987 [ 7] . The United States has also witnessed, within the context of a much larger AIDS epidemic than so far experienced in Europe, an increase in the proportion of reported AIDS cases identified as injectors - 58,788 out of 206,171 cases (29 per cent) by January 1992 [ 8] , compared to 9,488 out of 39,353 (24 per cent) by August 1987 [ 9] .

While drug injectors appear to constitute an increasing proportion of AIDS cases in Europe and the United States, there is much less certainty about the total number of HIV-positive injectors. WHO estimates of injecting drug use and HIV infection among injectors rely heavily on data provided by national agencies which generally represent perceptions by policy makers of the situation in their countries [ 10] . Although precise estimates remain scarce in most areas, a recent study collated figures supplied by national AIDS programmes in 38 countries containing 60 per cent of the global population [ 11] . There were an estimated 3.2 million drug injectors in those countries, with a prevalence rate of 101 per 100,000 population. it is against this background that the current study of injectors in 13 centres should be interpreted.

Methodology

Recruitment

The study guidelines recommended that each centre adopt a recruitment strategy designed to yield a sample of drug injectors as representative as possible, with respondents drawn from both "in-treatment" "and .out-of-treatment" sites. In-treatment sites were defined as those where injectors were being treated for drug-related problems. As the aim of the study was to interview "current injectors", it was recommended that all respondents should have injected within the previous two months, and those recruited from drug treatment settings should not have been in treatment for more than four weeks. Out-of-treatment sites covered a wide range of settings including needle and syringe exchanges, pharmacies, street sites, nightclubs, health centres and personal contacts. Thus, each centre implemented a strategy based on local conditions in order to achieve a multisite sample of injectors.

Study protocol and procedures

The interview procedure involved the administration of the interview schedule by a trained interviewer and a request for a blood and/or saliva sample. The schedule consisted of: an eligibility check; personal demographic information; and questions on drug use, needle and syringe sharing, sexual behaviour, HIV and AIDS knowledge and behaviour change, travel history and previous HIV testing. All behavioural questions refer to the period six months prior to the interview, with the exception of travel history, which covered the previous two years.

In view of the differing coding strategies and data storage systems used by collaborating centres, it was decided that the most efficient method of obtaining a basic comparative dataset would be to construct a form which could be easily completed by each centre. Accordingly, such a form was designed to collect information on key variables from the core questionnaire, IUV test results and the study methodology. It was deliberately selective, and some important areas of the questionnaire not dealing directly with behaviour of injectors were omitted (such as HIV and AIDS knowledge). While such a methodology has limitations, the principal aim of the exercise was to collate responses to the selected variables. Basic information was also sought on the total population of, and estimated number of injectors in, each centre. The resultant eight-page form was faxed to all centres. The methodology functioned successfully with no centres reporting any difficulty in completing the form prior to being returned to Glasgow. Tables were then constructed to enable comparison of the data from 13 centres.

Results

Centre characteristics

The first phase of data collection and analysis relates to the interval between October 1989 to March 1902. The periods of recruitment for each centre varied - from three months in late 1989 for Bangkok, to 19 months from January 1990 for New York. Thus, the number of interviews performed by each centre was also variable, though only three centres (Athens, Rio de, Janeiro and Santos) had completed less than 380.

As stated above, centres were asked to ensure that no more than 50 per cent of injectors be recruited from drug treatment settings. Figure I shows that compliance with this requirement was extremely high, while figure II indicates that, with the exception of Rome, at least 25 per cent of the sample at each centre included injectors who had never received treatment. These proportions should not be assumed to be necessarily representative of the proportion of all injectors in treatment in each centre, as they may be subject to bias arising from sampling strategies.

Sample characteristics

The mean age at first injection was similar in each centre, with a range from 17.5 years at Glasgow to 21.7 years at Bangkok (figure III). Excluding New York, the length of injecting at the time of interviewing was also similar, ranging from 6.8 years at Glasgow to 9.6 years at Bangkok and Rio de Janeiro. Although there are no simple explanations as to why the mean length of injecting in New York was 17 years, or why the current estimated prevalence of injecting was so high compared to other centres (see table 1), it is worth noting that the city has had a disproportionate share of injectors in both the United States and the world since the start of the twentieth century.

FigureI. I. Recruitment sites

Full size image: 1 kB, FigureI. I. Recruitment sites

Figure II. Cases of prior treatment for drug use

Full size image: 41 kB, Figure II. Cases of prior treatment for drug use

Figure III Age at first injection and duration of injecting drug use

Full size image: 41 kB, Figure III Age at first injection and duration of injecting drug use

Table 1. Profile of participating centres

 

WHO study

Detail of study area

Site

Period of recruitment

Number of interviews

Population

Estimated number of IDUs

Prevalence of IDUs (percentage)

Athens
2/91-7/91
200 4000000 12500 0.31
Bangkok
10/89-12/89
601 6000000 40000 0.66
Berlin
9/90-11/91
380 3400000 8000 0.24
Glasgow
1/90-12/90
503 1115700 9400 0.84
London
6/90-11/90
534 6794400 16000 0.24
Madrid
5/90-11/90
472 3800000 24000 0.63
Naples a/
4/90-4/91
693 3150000 30000 0.95
New York
1/90-7191
1313 7000000 200000 2.86
Rio de Janeiro
9/90-7/91
240 6000000 30000 0.50
Rome
5/90-10/90
487 3500000 12000 0.34
Santos
4/91-8/91
85 520000 10000 1.92
Sydney
5/90-2/91
424 3700000 8000 0.21
Toronto
5/91-3/92
458 3900000 11000 0.28

Note: IDU = intravenous drug user.

a/ Cagliara, Milan, Naples, Verona.

In all centres, injectors were predominantly male, though over 30 percent of those recruited at Berlin, in London and at Santos were female (see figure IV). of the Bangkok sample, only 5 percent were female. Although sampling biases could account for some of the variation, it is considered that these proportions are reasonably representative of the true gender distributions for injecting drug use in each centre.

Patterns of drug injecting

For all centres, over 80 per cent of injectors were found to inject on a daily basis in the six months prior to interviewing. Figure V shows the most commonly injected drug in each centre and the frequency with which that drug was injected. Heroin was the most popular drug in nine centres, cocaine in the two Brazilian centres and at Toronto, and the opiate buprenorphine (trade name, Temgcsic) at Glasgow.

Figure IV. Gender

Full size image: 41 kB, Figure IV. Gender

Figure V. Most frequently injected drugs

Full size image: 56 kB, Figure V. Most frequently injected drugs

Needle and syringe sharing

With regard to HIV transmission, one of the crucial variables is the use of a needle and syringe that has already been used by someone else. Figure VI shows that in each centre, at least 45 per cent of the sample claimed never to have shared in the previous six months, and that at least 70 per cent never shared more often than on a monthly basis. This indicates that the majority of injectors, most of whom inject daily, are minimizing their risk of infection. In most centres, however, there was a core of drug users, 13 per cent in total, who continued to share on a daily or weekly basis.

The spread of HIV among injecting drug users from the early 1980s onwards gave rise to the concern that injectors engaging in risk behaviours outside their home areas could import or export HIV to previously unaffected localities. Figure VII shows that up to 60 per cent of respondents injected outside their home areas in the two years prior to interview, and of these (figure VIII), approximately 20 per cent shared injecting equipment.

Figure IX illustrates that most injectors who continued to share injecting equipment made some effort to clean previously used equipment, although figure X shows that the cleaning methods used were often unsatisfactory. Steeping in bleach is almost certainly the most efficient viricidal procedure, while steeping in alcohol and boiling in water are practical alternatives. Clearly those centres where rinsing with hot and particularly cold water are the predominant methods employed have considerable cause for concern - over 60 per cent of injectors who shared equipment at Bangkok, Madrid, Rio de Janeiro and Santos used rinsing in cold water most frequently.

Sexual behaviour

While it is widely believed that drug users who take depressants (such as opiates and tranquillizers) practise less sexual intercourse than the norm [ 12] , respondents in the present study (figure XI) were at least as sexually active as their peers in the general population of the United Kingdom of Great Britain and Northern Ireland [ 13] .

Of particular importance is unprotected sexual intercourse. For those reporting intercourse with regular sexual partners, most respondents reported never using condoms (figure XII). It can therefore be assumed that the risk of HIV being transmitted sexually from injectors to other injectors and to non-injectors remains extremely high, particularly in centres where large numbers of injectors are already infected. For the smaller subsample of injectors who had sexual intercourse with casual partners (figure XIII), there was greater use of condoms. However, only in New York did over half of those reporting casual sex report using condoms "always" or "mostly", while at Athens, Glasgow, Rio de Janeiro and Santos, more than 70 per cent either "never" or "occasionally" practised safe sex with their casual partners.

Figure VI. Frequency of injecting with equipment previously used by someone else

Full size image: 53 kB, Figure VI. Frequency of injecting with equipment previously used by someone else

Figure VII. Frequency of injecting outside study area in last two years

Full size image: 50 kB, Figure VII. Frequency of injecting outside study area in last two years

Figure VIII. Frequency of sharing outside study area in last two years a/

Full size image: 54 kB, Figure VIII. Frequency of sharing outside study area in last two years a/

Figure IX. Frequency of needle and syringe cleaning a/

Full size image: 37 kB, Figure IX. Frequency of needle and syringe cleaning a/

Figure X. Method most commonly used to clean needles and syringes a/

Full size image: 47 kB, Figure X. Method most commonly used to clean needles and syringes a/

Figure XI. Frequency of sexual intercourse (vaginal, anal, oral) with someone of the opposite sex

Full size image: 58 kB, Figure XI. Frequency of sexual intercourse (vaginal, anal, oral) with someone of the opposite sex

Figure XII. Frequency of condom use for respondents reporting sexual intercourse with regular partners

Full size image: 51 kB, Figure XII. Frequency of condom use for respondents reporting sexual intercourse with regular partners

Figure XIII. Frequency of condom use for respondents reporting sexual intercourse with casual partners

Full size image: 44 kB, Figure XIII. Frequency of condom use for respondents reporting sexual intercourse with casual partners

Figure XIV illustrates that a small but appreciable number of male injectors in most centres reported having sexual intercourse with other men. The proportion of male respondents reporting homosexual activity in the two Brazilian cities was considerably higher than elsewhere.

HIV testing and prevalence

Unlike the data on risk behaviour which- related to current behavioural activity, the results of, HIV testing may reflect past rather than current risk behaviour. Nevertheless, as a parallel exercise it was considered important to measure the prevalence of HIV among injectors. In all centres, except for Rio de Janeiro and Rome, participation rates were high. Blood and/or saliva specimens were requested for testing (table 2), and the HIV prevalence rates for analysable specimens are shown in figure XV.

HIV prevalence rates of 5 per cent or less were found at Athens, Glasgow, Sydney and Toronto. Intermediate rates of between 10 per cent and 20 per cent were identified at Berlin, in London, and at Naples and Rome. High rates of between 30 and 50 per cent were seen at Bangkok, Rio de Janeiro and in New York and rates of 60 per cent were seen at Madrid and Santos. It is likely that the findings at Bangkok, Rio de Janeiro and Santos reflect HIV transmission which occurred mainly in the late 1980s, while in New York and other European centres many injectors were infected in the early to middle 1980s.

Discussion

In recent years, scientific understanding of injection drug use has improved because of its association with MV infection although hitherto there has been a lack of comparative epidemiological and behavioural data. Clearly there are cultural differences among centres, participating in the present study, and it would be wrong to overinterpret the data, particularly with regard to possible links between HIV prevalence and current risk behaviour. At the current stage, the analysis was limited to comparisons of frequencies among centres to assess commonalities and differences across settings which might inform interventions designed to limit the spread of HIV infection. Data on changes in behaviour and HIV prevalence have not yet been collated for the 13 centres.

Figure XIV. Frequency of sexual intercourse between men

Full size image: 49 kB, Figure XIV. Frequency of sexual intercourse between men

Figure XV. Prevalence of HIV

Full size image: 48 kB, Figure XV. Prevalence of HIV

Table 2. HIV testing: salivary and blood tests

 

Salivary tests

Blood tests

 

Requested a/

Obtained b/

Requested a/

Obtained b/

Site

Number of interviews

Number

Percentage

Number

Percentage

Number

Percentage

Number

Percentage

Athens
200 200 100 200 100 200 100 199 95
Bangkok
601
NR
---
NR
---
601 100 601 100
Berlin
380 185 49 185 100 195 51 187 96
Glasgow
503 500 99 464 93 122 24 114 93
London
534 534 100 512 96 46 9 28 6
Madrid
472
NR
---
NR
---
320 68 209 65
Naples
693 693 100 672 97 693 100 380 55
New York
1313 66 5 66 100 909 69
ma
95
Rio de Janeiro
240
..
..
..
..
240 100 46 19
Rome
497
..
..
253
..
NR
-
NR
-
Santos
85
NR
-
NR
-
100 100 97 97
Sydney
424
NR
-
NR
-
..
..
326
..
Toronto
458 458 100 447 98 458 100 434 95

Note: NR = not requested.

a/ As percentage of cases interviewed.

b/ as percentage of tests requested.

A preliminary assessment indicates that there are similarities across centres in many aspects of current behaviour of injectors. Of particular importance are the relatively low levels of sharing of injecting equipment, compared to levels of sharing reported in many cities during the middle to late 1980s [ 14] . Furthermore, injectors continuing to share, for whatever reason, nearly always clean their equipment, albeit often employing inefficient methods, prior to injecting themselves. These findings are encouraging in view of the widely differing levels of new needle and syringe availability; in some centres, injecting equipment can be purchased legally or obtained free of cost, while in others, there are legal impediments to obtaining new injecting equipment.

The high level of sexual activity among injecting drug users challenges prevailing notions of sexual behaviour of injectors, and suggests that even injectors with serious opiate and tranquillizer dependency are just as sexually active if not more so than the general population. The low rate of condom use, with casual and particularly regular sexual partners, many of whom are not themselves injectors, gives rise to the concern that sexual transmission of MV may become an increasingly important route among injectors and from injectors to non-injectors. Again, as with sharing of injecting equipment, there is consistency across centres despite variations in condom availability.

It has recently been observed that "almost all preventive programmes for injectors now focus on both sexual and injection risk behaviour"; however, where comparisons have been made, "researchers have found more change in injection risk than in sexual risk behaviour" [ 15] . While condom use is influenced by social and personal circumstances [ 16] , the willingness of injectors to reduce injecting risk behaviour to a greater extent than sexual risk behaviour is sometimes interpreted as being inconsistent. Yet the premise on which this view is based, that people cease risky behaviour when provided with adequate information or fear arousal messages, may be flawed [ 17] . People engage in many activities involving risk, for pleasure and excitement, in full knowledge of the dangers involved. Thus, it may be rational from the injector's standpoint not to share injecting equipment (since this does not reduce appreciably the pleasure experienced by injecting), but to refrain from using condoms which are often perceived to decrease the pleasure associated with sexual intercourse [ 16] . This does not mean that attempts to increase condom usage should not be made, rather that, it may be difficult to change sexual risk behaviour to the same degree as injecting behaviour.

One topic not addressed in the current analysis is the issue of AIDS awareness and HIV transmission among injectors. However a recent study comparing two participating centres (Glasgow and New York) found that, relative to a wide range of other predictors, AIDS awareness is a good predictor of behavioural change [ 18] , [ 19] . While the source of injectors' knowledge was not investigated further, the findings suggest that campaigns designed to increase AIDS awareness may be an important means of effecting behavioural change. This issue is of current importance in view of the high HIV prevalence rates found among participating centres in the developing world. Those centres and other areas in the developing world where drug injecting is common are vulnerable to the potentially explosive spread of HIV. That has been amply illustrated by new epidemics in the State of Manipur in India [ 20] and at Yangon, Myanmar [ 21] , where prevalence rates of over 80 per cent and 50 per cent, respectively, have been recorded. It is in these densely populated areas of Asia which have poorly developed health care and educational and economic infrastructures that HIV may exact its greatest toll over the next decade unless effective interventions are implemented.

Only a small part of the dataset from the study has been presented in the present paper, with the aim of highlighting differences and similarities among the 13 centres and providing basic comparative data for policy makers. The methodology of the present analysis, while useful in achieving these limited goals, is nevertheless restrictive. Further comparative analyses will require the merging of all datasets into a single computerized file. This will constitute a unique resource for those wishing to explore more complex dimensions of the behaviour of drug injectors.

Acknowledgements

The research reported in the present paper was funded by the World Health Organization, the United Nations International Drug Control Programme and national funding bodies, including the following: State University of Rio de Janeiro (Brazil); National Health Research and Development Programme, Health and Welfare Canada (Canada); Federal Ministry of Health (Germany); Istituto Superiore di Sanit, Ministry of Health of Italy; Fondo de Investigaciones Sanitarias (Spain); Department of Health, Bangkok Metropolitan Administration (Thailand); Medical Research Council (United Kingdom of Great Britain and Northern Ireland); National Institute on Drug Abuse (United States of America).

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