Search

Background: Epidemiological studies among drug users are often based on retrospective self-reports. However, among others, memory failure, being under the influence of drugs, psychopathology, misunderstanding of questions and socially desirable answering may generate inaccurate reporting., Methods: This study validated self-reported current (methadone dosage) and medium-term (main location of methadone dispensing and frequency of methadone programme attendance over the previous 4-6 months) aspects of methadone treatment in the Amsterdam AIDS cohort study among drug users, using data of the Central Methadone Register. In addition to descriptive measures, logistic regression analysis was used (adjusted for intra-individual correlation) to identify subgroups with incorrect reporting. Data collected at 4406 visits of 505 cohort participants were analysed., Results: Current methadone dosage was accurately reported (unweighted kappa [kappa]: 0.94, weighted kappa [kappa W]: 0.97). A low methadone dosage, short duration of school education and depressive or euphoric mood during the interview were significant and independent predictors of incorrect reporting of methadone dosage. For main location of dispensing kappa was 0.82, for frequency of programme attendance kappa was 0.53 and kappa W 0.87. There was a tendency to reporting the extreme answering categories. Infrequent programme attendance was the only significant predictor of incorrectly reporting frequency of programme attendance., Conclusions: Drug users are able to give valid self-reports in a setting where social desirability does not play an important role. The main reasons of incorrect reporting were impaired cognitive functioning, memory failure and misunderstanding of questions.

Aims: To determine levels of injecting drug use and sexual risk behaviours in injecting drug users during and immediately following imprisonment in The Netherlands., Design, Setting and Participants: Cross-sectional survey of drug injectors attending methadone clinics, a sexually transmitted disease clinic and a central research site in Amsterdam. The mean age of the 188 participants was 35 years, 78% were male and 34% had HIV antibodies., Measurements: Self-reported drug use and sexual behaviours during the last period of imprisonment in Dutch prisons within the previous 3 years and injecting drug use in the week following release from prison., Findings: A period of imprisonment in the preceding 3 years was reported by 188 (41%) of 463 interviewed drug injectors. The mean duration of last imprisonment was 3.6 months. Any use of cannabis, heroin or cocaine during imprisonment was reported by 55%, 37% and 20%, respectively. Five injectors (3%) admitted to having injected in prison, but no sharing of needles and syringes was reported. Vaginal or anal sex was reported by two (1%) of the men and none of the women. Relapse to drug injecting during the week following release from prison was reported by 78/186 (42%) participants, in most cases (34%) at the very first day of release. Drug use behaviours during imprisonment were similar for those who were designated current injectors at the time of imprisonment and those who were not, but injecting in the first week following release from prison was far higher among 'current' injectors (63%) than among those who were not (11%)., Conclusions: Contrary to findings from other countries, low levels of HIV risk behaviours occur among imprisoned drug injectors in The Netherlands. Intra-prison HIV preventive measures should be considered taking into account the nationally, regionally or locally varying conditions within the existing prisons.

The impact of human immunodeficiency virus (HIV) infection and other risk factors on mortality was studied in a cohort of Dutch injection drug users and drug users who did not inject. Participants were recruited between 1985 and 1992 and followed up through 1993. Vital status was ascertained through repeat visit information, supplemented by population register data. A total of 77 deaths were recorded among 632 drug users, for a mortality rate per 1,000 person-years of 7 for HIV-negative noninjection drug users, 18 for HIV-negative injection drug users, and 64 for HIV-positive injection drug users. In multivariate analyses, limited to injection drug users, a positive HIV serostatus, age above 40 years, and using benzodiazepines several times daily were significantly associated with an elevated risk of death, both for death from all causes and for death preceding acquired immunodeficiency syndrome (AIDS) diagnosis (pre-AIDS). For pre-AIDS death, the adjusted relative risk associated with HIV infection was 2.2 (95% confidence interval 1.3-3.7). Only 38% of HIV-infected injection drug users who died were diagnosed with AIDS. However, 76% of HIV-infected injection drug users who died without AIDS diagnosis had evidence of immunosuppression (CD4 count < 500/microliters). Daily use of methadone and participation in needle and syringe exchange schemes were not associated with lower mortality rates. This study illustrates in a group of injection drug users with a 30% HIV seroprevalence and a high background mortality the profound influence on mortality that HIV infection has gained.

Objective: To determine trends in commercial sexual risk behaviour among drug-using prostitutes in Amsterdam after local and national prevention campaigns began in 1987., Design: A subgroup of 281 drug-using prostitutes was selected from a comprehensive, open cohort study of drug users in Amsterdam., Methods: Cross-sectional (at intake) and within-person trends in sexual behaviour were evaluated. Person-time analysis was used to determine trends in incidence of sexually transmitted disease (STD)., Results: From 1986 to 1992, 'always' use of condoms in the 6 months preceding intake increased from 21 to 58% (P < 0.001) and the number of commercial contacts declined from 84 to 64 per month (P = 0.06). Consequently, the mean number of unprotected commercial contacts declined from 26 to nine per month (P < 0.001). Temporal trends within individual prostitutes from visits 1 to 8 (mean interval between visits, 4 months) showed a somewhat larger risk reduction than the cross-sectional trends. From 1989 to 1992, the STD incidence declined from 61 to 40 episodes per 100 person-years (P = 0.06). Prostitutes residing in Amsterdam for shorter time periods reported more STD and a relatively small core group reported the majority of STD episodes. At intake, when < 10% of all participants knew their HIV serostatus, HIV-positive prostitutes reported significantly lower levels of condom use and more STD than HIV-negatives, while, after learning their serostatus, levels of condom use and the STD-incidence were comparable. Prevalent and incident HIV infections were not observed among non-injecting prostitutes., Conclusions: Drug-using prostitutes have reduced sexual risk behaviour. There is evidence for the effectiveness of HIV testing and counseling. At present, new infections among clients of drug-using prostitutes are expected to occur, although not on a large scale. Since the incidence of STD continues to be high, it is important to monitor the spread of HIV among heterosexuals, including prostitutes and their clients, closely.

An investigation into the prevalence of human papilloma virus (HPV) infection, abnormal cervical cytology and the relationship between HIV- and HPV infection was done in a group of intravenously (IV) and non-IV drug-using prostitutes. From July 1991 through May 1992, hard drug-addicted prostitutes attending a sexually-transmitted-disease (STD) clinic in Amsterdam were recruited. A questionnaire was administered to obtain demographic characteristics, and medical and STD history. Apart from routine STD examination, cervical scrapes for cytology and samples for HPV DNA detection by polymerase chain reaction (PCR) were collected. Some of the women included in this study also participated in HIV studies among drug users. Their data on HIV- and immunologic status could be combined. A total of 121 women entered the study; 25 women were HIV-seropositive, 44 women were HIV-negative, and the HIV status of 52 women was unknown. All 25 HIV-positive women had normal Pap smears, two of the 44 HIV-negative women had a Pap smear III A, and in the HIV-unknown group, two women with Pap III A and one with Pap III B were found. Eight of the 25 (32%) HIV-positive women were HPV DNA-positive, three of the 44 (7%) HIV-negative women and 10/52 (19%) of the HIV-unknown group. Logistic regression analysis showed that in the total group, presence or cervical HPV DNA was associated with HIV infection (order ratio [OR] for HIV-positives 7.8, 95% confidence interval [CI] 1.8 to 34.6) and with diagnosis of condylomata acuminata at entry to the study (OR 7.5, 95% CI 1.5 to 36.5).(ABSTRACT TRUNCATED AT 250 WORDS)

Objective: to assess whether male prostitution is an independent risk factor for HIV infection among male (intravenous and nonintravenous) drug users., Design: a cross-sectional study., Setting: various low-threshold methadone clinics and the sexually transmitted diseases clinic of the Municipal Health Service in Amsterdam and a drug-treatment centre in The Hague., Participants: 343 male intravenous drug users and 106 male non-intravenous drug users., Main Outcome Measures: characteristics concerning drug use behaviour, sexual behaviour, and sociodemography, related to prostitution and HIV-antibodies., Results: of the 449 study participants, 88 (20%) reported a history of prostitution; no differences were found between intravenous and non-intravenous drug users. Younger age, West German nationality, and having had private homosexual sex contacts, were independent predictors of a history of prostitution. Independent predictors of HIV infection were (1) longer residency in Amsterdam; (2) having had predominantly homosexual private sex contacts; (3) longer duration of intravenous drug use; and (4) frequent needle sharing., Conclusion: no evidence was found to suggest that male prostitution in itself contributed to the risk of HIV infection.

The prevalence, risk factors, and incidence of hepatitis C virus (HCV) infection were studied in a cohort of drug users in Amsterdam. In intravenous drug users, the seroprevalence was 74% (224/304) versus 10% (4/42) in nonintravenous drug users. Risk factors independently associated with HCV antibody seropositivity were history and duration of intravenous drug use and frequency of injections. Daily smoking of heroin in the previous 6 months was independently associated with the absence of HCV antibodies. Periods of fever, tiredness, and diarrhea in the preceding 6 months were associated with HCV antibodies even after correction for human immunodeficiency virus infection. The incidence rate of HCV infection appeared high and stable over the years 1986 to 1989. Thus, HCV infections are common among intravenous drug users and are mainly due to the intravenous use of drugs.

In December 1985 we started a study to determine the prevalence and risk factors of HIV infection among drug users and drug-using prostitutes in Amsterdam. Recruitment took place at methadone posts (not drug-free; i.e. a low-threshold programme on which some drug users continue to use hard drugs, but at a lower level) and the weekly evening sexually transmitted diseases (STD) clinic for drug-addicted prostitutes. Three hundred and ten drug users have so far been tested and interviewed. Eighty-one per cent reported intravenous drug use; 83% of the 166 females and 15% of the 144 men reported prostitution. Female prostitutes practised mainly vaginal and orogenital intercourse and reported frequent use of condoms (89% of vaginal and 64% of orogenital contact). Male prostitutes practised mainly orogenital and manual contact. At entry 88 of the 310 (28%) were HIV-antibody-seropositive; 85 of these 88 were intravenous drug users and three were male homosexuals. HIV-antigen was detected in two seropositive and one seronegative intravenous drug-user. Antibodies to HTLV-I were found in four out of 308. Risk factors independently associated with HIV-antibody seropositivity among intravenous drug users were: frequency of borrowing used needle or syringe, date of first intravenous drug use, recent intravenous drug use, time living in Amsterdam and German nationality. Of medical history data, an attack of herpes zoster in the previous 5 years had the greatest value in the prediction of the presence of HIV antibodies (relative risk 20.90; 95% confidence interval 2.41-167.27).(ABSTRACT TRUNCATED AT 250 WORDS)

To assess the potential role of drug using prostitutes in the heterosexual transmission of human immunodeficiency virus (HIV), 117 prostitutes, recruited from December 1985 to November 1987 at a weekly evening sexually transmitted diseases (STD) clinic for drug using prostitutes only, were studied for the prevalence of HIV and STD. Intravenous drug use was reported by 96 (82%) of the women. Antibody to HIV was found in 35/117 (30%) women, all but one of whom had been using drugs intravenously. Most (73, 62%) of the prostitutes reported having had more than 2000 clients each in the preceding five years. In the six months preceding enrollment to the study they had practised mainly vaginal (106/117) and orogenital (82/117) intercourse; 90% (105/117) reported frequent use of condoms in vaginal intercourse and 65% (68/105) in orogenital intercourse. Despite frequent condom use, 81% (84/104) contracted one or more STD in this period. Considering the high incidence of HIV and STD and the finding by others that the presence of STD may facilitate transmission of HIV, we conclude that the potential for HIV transmission from these prostitutes to their clients (and vice versa) was clearly present.

We evaluated the impact of a needle/syringe exchange program among 263 drug users in the period December 1985 to April 1988. Participants in this study were asked about their risk-behavior at three different visits. We found no increase in the proportion injecting drugs or in the frequency of intravenous drug use. A strong decrease in borrowing and lending of used needle/syringes was found and this behavioral change was not dependent on learning human immunodeficiency virus (HIV) serostatus. Although use of the exchange program increased over time, reduction in needle sharing was mainly an effect of the study with only a limited impact of the exchange program. We conclude that ample provision of needles and syringes is an important starting point but in itself not enough to produce the necessary drastic change in risk behavior. Intensive counseling of the drug user is also needed.