Drug network characteristics as a predictor of cessation of drug use among adult injection drug users: a prospective study.

Few studies have examined recovery from opiate and cocaine dependence without treatment, referred to as "natural recovery," "spontaneous recovery," and "spontaneous remission." The present study examined the relationship between network characteristics and cessation of heroin, cocaine, and crack use in a sample of underclass inner-city injection drug users in Baltimore, Maryland. Participants were enrolled in an experimental human immunodeficiency virus (HIV) preventive intervention. Between the baseline and follow-up interviews, which averaged 5.2 months, 24 (7%) of 335 participants reported ceasing to use heroin, cocaine, and crack. Individuals who had reported cessation of drug use at follow-up had reported at baseline a smaller proportion of their network members with whom they used drugs (p < .02). Using multiple logistic regression analyses and adjusting for baseline drug use, enrollment in drug treatment, and demographic and background variables, cessation of drug use was associated with a lower proportion of personal network members in one's drug network (odds ratio [OR] = 25.4, p < .05). The data from this study suggest that network members have potential for social influence on the cessation of drug use.     

Type and pattern of illicit drug use and access to health care services for HIV-infected people

Approximately 28% of HIV-infected people in treatment in the United States report using illicit drugs. Illicit drug users have poorer course of HIV disease than non-drug users, which is thought to be due to their irregular use of HIV medical services. We examined associations between type (cocaine versus opioids) and pattern of drug use (drug use at baseline, 6-month follow-up, both periods, and nonuse) and health care utilization for a large sample of HIV-infected individuals drawn from a multisite project that evaluated the impact of medical outreach interventions for populations at risk of poor retention in HIV care. Across all types and patterns of drug use, drug users were more likely to have suboptimal ambulatory care, miss scheduled appointments, use the emergency department, have unmet support services needs, and were less likely to take antiretroviral medications. Additionally, while people who started using drugs during the follow-up period and consistently used drugs across both periods differed from nonusers on missed appointments (odds ratio [OR] = 2.20 for starters versus nonusers, OR = 2.92 for consistent users versus nonusers), emergency department use (OR = 4.93 for starters versus nonusers, OR = 2.24 for consistent users versus nonusers), and antiretroviral medication use at follow-up (OR = 0.23 starters versus nonusers, OR = 0.19 for consistent users versus nonusers), those who stopped using drugs after the baseline period did not differ from nonusers. We conclude that health care utilization is poorer for people who use illicit drugs than those who do not, and stopping drug use may facilitate improvements in health care utilization and HIV outcomes for this population.     

Choosing drug use measures for treatment outcome studies. I. The influence of measurement approach on treatment results

Drug use is measured in a number of different ways in drug treatment outcome studies. Different measures of outcome may yield different results, making comparison across studies difficult. The utility, sensitivity, and level of measurement of five categories of measures are reviewed. It is suggested that research focus on examining the properties of existing drug use measures, on developing methods of evaluating timing and sequence in the relapse process, and on standardizing measurement approaches across studies.     

Psychiatric status and HIV risk reduction among residential drug abuse treatment clients

We investigated the associations of psychiatric symptoms and diagnoses with HIV risk behaviors among 405 clients of two United States residential drug abuse treatment programs at admission and at follow-up. Measures of psychiatric status included the Beck Depression Inventory (BDI), selected diagnoses assessed with the Diagnostic Interview Schedule (DIS-III-R) and the Addiction Severity Index psychiatric composite score (ASI-P). Measures of risk behaviors included: drug injection risk (including sharing and bleaching of needles and syringes), multiple sexual partners and condom use. In multivariate analyses, the BDI at baseline and change in the BDI to follow-up were strongly associated with drug use at follow-up (both injection and non-injection), but not with other risk behaviors. In contrast, psychiatric diagnoses were not statistically associated with risk behaviors at follow-up when baseline behavior was controlled.     

Assessment and control for confounding by indication in observational studies.

In the evaluation of pharmacologic therapies, the controlled clinical trial is the preferred design. When clinical trial results are not available, the alternative designs are observational epidemiologic studies. A traditional concern about the validity of findings from epidemiologic studies is the possibility of bias from uncontrolled confounding. In studies of pharmacologic therapies, confounding by indication may arise when a drug treatment serves as a marker for a clinical characteristic or medical condition that triggers the use of the treatment and that, at the same time, increases the risk of the outcome under study. Confounding by indication is not conceptually different from confounding by other factors, and the approaches to detect and control for confounding--matching, stratification, restriction, and multivariate adjustment--are the same. Even after adjustment for known risk factors, residual confounding may occur because of measurement error or unmeasured or unknown risk factors. Although residual confounding is difficult to exclude in observational studies, there are limits to what this "unknown" confounding can explain. The degree of confounding depends on the prevalence of the putative confounding factor, the level of its association with the disease, and the level of its association with the exposure. For example, a confounding factor with a prevalence of 20% would have to increase the relative odds of both outcome and exposure by factors of 4 to 5 before the relative risk of 1.57 would be reduced to 1.00. Observational studies have provided important scientific evidence about the risks associated with several risk factors, including drug therapies, and they are often the only option for assessing safety. Understanding the methods to detect and control for confounding makes it possible to assess the plausibility of claims that confounding is an alternative explanation for the findings of particular studies.     

Interventions with injection drug users in Ukraine

Aims   To assess the effectiveness of a brief human immunodeficiency virus (HIV) testing and counseling intervention compared to a more time-consuming and expensive street-based intervention with injection drug users (IDUs).
Design   Cross-over experimental design in which 900 IDUs were recruited, followed by a 'wash-out' period with no recruitment, a reversal of intervention assignment areas and an additional recruitment of 900 IDUs with baseline and 6-month follow-up assessments.
Setting   Kiev, Odessa and Makeevka/Donesk Ukraine.
Participants   A total of 1798 IDUs.
Measurements   HIV testing and audio computer-assisted self-interview (ACASI) data on socio-demographics, drug use and injection and sex-related risk behaviors.
Findings   Participants in both conditions reduced their injection and sex risks significantly; however, there was little difference in outcomes between conditions. IDUs who knew they were HIV-infected at baseline were significantly more likely to practice safe sex than those unaware or HIV-negative; those who first learned that they were infected at baseline changed their safe sex practices significantly more than those who already knew that they were infected at baseline and those who were HIV-negative. Younger IDUs and those injecting for a shorter period of time reported higher injection and sex risk behaviors following interventions.
Conclusions   Awareness of HIV infection by street-recruited drug injectors is associated with reduced sex risks. Additional interventions are required for younger IDUs and those injecting for shorter periods of time.     

Covariates of cannabis use progression in a representative population sample of adolescents: a prospective examination of vulnerability and risk factors

Aims/design. This study reports findings concerning risk factors for first, "repeated" and "regular" use of cannabis in respondents (N = 1228) who were aged 14-17 years at the outset (i.e. at "baseline") as part of a longitudinal prospective community study (EDSP). Risk factors were assessed at baseline or by separate interviews with the respondents' parents. Cumulative life-time cannabis use was the main outcome measure in this study-assessed by information from both the baseline and the follow-up investigation at an average of 19.7 months later. A cumulative logistic regression model was used to estimate associations. Findings. Using seven of a total of 25 variables examined, the final model classified 72.1% of respondents correctly. Family history of substance use disorders, self-esteem and competence, unconditional commitment to not using drugs, immediate availability of drugs, peer group drug use and previous history of nicotine dependence and alcohol use disorders all contributed significantly to the final model, predicting the progression to cannabis use from "no use", to "one time only", "repeated use", and "regular use". Conclusion. In addition to well-documented risk factors such as peer group pressure, availability, low self-esteem and competence, findings suggest that family history and prior experiences with legal drugs play a significant role in the early development of cannabis consumption in teenagers.     

Thrombosis and drug-eluting stents: an objective appraisal.

Stent thrombosis (ST) after percutaneous coronary intervention has been the focus of intense interest because of its attendant morbidity and mortality. There is controversy about several facets of the problem. These include the frequency of ST with drug-eluting stents (DES) versus bare-metal stents (BMS), the timing of the event, clinical consequences, risk factors, adjunctive therapy, and new preventive approaches. Information has accrued rapidly from several sources, including randomized controlled clinical trials of DES versus BMS in carefully selected subsets of patients and registry experiences in larger patient groups, which provide a more universal real-world picture. The results from these different data sets are not completely concordant. However, several general conclusions can be made: 1) ST is an infrequent but very severe complication of both BMS and DES; 2) at the present time, during 4 years of follow-up from randomized controlled trials that compared DES and BMS, there is no apparent difference in overall ST frequency, although the time course for occurrence appears to differ, with a relative numeric excess of ST late after DES implant; 3) despite this relative imbalance, no differences in the end points of death or death and infarction between DES and BMS are observed; 4) longer-term follow-up of these patients as well as larger angiographic and clinical subsets of patients who receive this technology outside of randomized trials are required to fully study this issue; and 5) advances in stent platforms for drug elution as well as adjunctive pharmacologic therapy are being evaluated to enhance long-term safety.     

Housing Status and HIV Risk Behaviors: Implications for Prevention and Policy

This paper examines housing as a contextual factor affecting drug and sexual risk behaviors among HIV positive people using pooled interview data from 2149 clients presenting for services at 16 medical and social service agencies participating in a multi-site evaluation study. The odds of recent drug use, needle use or sex exchange at the baseline interview was 2-4 times as high among the homeless and unstably housed compared to persons with stable housing. Follow-up data collected 6-9 months after baseline showed that change in housing status was associated with change in risk behaviors. Persons whose housing status improved between baseline and follow-up significantly reduced their risks of drug use, needle use, needle sharing and unprotected sex by half in comparison to individuals whose housing status did not change. In addition, for clients whose housing status worsened between baseline and follow-up, their odds of recently exchanging sex was over five times higher than for clients whose housing status did not change. The provision of housing is a promising structural intervention to reduce the spread of HIV.     

Assessing the differential impact of an hiv prevention intervention: who's putting the message into practice?

Recent data suggest that educational interventions aimed at reducing HIV risk behaviors have shown some success. Nonetheless, HIV risk behaviors are not always reduced by interventions and probably do not reduce risk behavior randomly. That is, the success of interventions may be related to participant characteristics. Identifying participant characteristics related to both intervention completion and reduction in risk behaviors may be useful for further developing explanatory models of health behavior and for targeting and customizing interventions. In this study differences between participants who completed an AIDS educational intervention (N = 741) and those who did not complete the intervention are first examined (N = 652) and then variables related to reducing drug and sexual risk behaviors among those who completed the intervention and follow-up interviews are examined. Results show that the majority of respondents report decreasing five out of six risk behaviors, with the smallest percentage (48.8%) decreasing rates of unprotected sex and the largest percentage (83.4%) decreasing frequency of drug injection. Different variables were found to be related to changes in the various risk behaviors. However, some relatively consistent results emerge. For all risk variables, the frequency of the specific behavior at baseline predicted the amount of change in that behavior, with those having higher levels of risk behaviors reducing their behavior the most. Positive HIV test results significantly decreased three of the four sexual risk behaviors examined, and living in a very rural area was found to be significantly related to three of the six risk behaviors. However, perceived chance of getting AIDS did not significantly reduce any of the risk behaviors. Gender and education level were also not related to changes in any of the risk behaviors. Implications include the importance of developing approaches to retain higher proportions of younger participants, males and homeless in interventions. It is particularly important to develop specific approaches to retain women in interventions. Because very rural participants were more likely to decrease crack use and alcohol or drug use with sex, rural interventions should target these behaviors at the outset of the intervention.     

Association of traditional risk factors with cardiovascular death across 0 to 10, 10 to 20, and >20 years follow-up in men and women

Previous studies have evaluated the strength of the association between traditional risk factors and cardiovascular disease (CVD) across varying lengths of follow-up in men. However, to our knowledge, little is known regarding the behavior of these risk factors across time in women. Thus, we sought to determine the association between traditional risk factors in men and women across follow-up periods of 0 to 10, 10 to 20, and >20 years. We studied 9,033 men and 7,575 women (ages 40 to 59 years) from 1967 to 1973 from the Chicago Heart Association Detection Project in Industry. Multivariable-adjusted Cox proportional hazard models were constructed to compare the hazard ratios (HRs) and 95% confidence intervals (CI) for CVD risk factors measured at baseline across different periods of follow-up (0 to 10, 10 to 20, and >20 years). In women, the HRs for smoking and diabetes mellitus were strongest at 0 to 10 years (HR 5.38, 95% CI 2.99 to 9.67 and 3.84, 95% CI 1.82 to 8.13, respectively) but decreased at >20 years (HR 1.71, 95% CI 1.48 to 1.97 and 1.60, 95% CI 1.10 to 2.32, respectively). In men, the HR (per 4 kg/m(2)) for body mass index appeared to increase (0 to 10 years, 1.01, 95% CI 0.90 to 1.14; >20 years, 1.20, 95% CI 1.13 to 1.28). In women, the association was similar across all follow-up periods. For both men and women, the HR for total serum cholesterol remained unchanged across the follow-up. In conclusion, we found gender differences in the patterns of association between risk factors measured at baseline and CVD death across different periods of follow-up. In women, the increased risk associated with both diabetes mellitus and smoking was most prominent in the early follow-up periods.     

Self-rated health and mortality in older men and women: a time-dependent covariate analysis

Although the relation between self-rated health (SRH) and mortality is widely known, most of the studies have relied in baseline measurements unheeding the dynamics of the phenomenon. Our aim was to analyze how SRH both as a constant and as a time-dependent covariate predicts mortality in older men and women and to compare these different approaches. Subjects consisted of 110 male and 208 female (n=318) residents in the city of Jyv?skyl?, central Finland, aged 75 years at the baseline in 1989. The follow-up data was gathered in 1994 and mortality was followed for 10 years. Results showed that poor SRH was strongly associated with higher mortality risk in women in all models. In men, the association was found only in time-dependent and 5 year follow-up models and these associations were explained by baseline health status. To conclude, our analyses showed that there are gender differences in association between SRH and mortality and that the use of time-dependent covariate in a Cox regression model enables advantage to be taken of all the information in a longitudinal study design.     

The methotrexate therapeutic response in rheumatoid arthritis

OBJECTIVE: Methotrexate (MTX) is used frequently as a disease modifying antirheumatic drug (DMARD) for rheumatoid arthritis (RA), and patients tend to continue taking this drug for longer periods than alternative single agents. The shape of the therapeutic response beyond one or 2 years, however, has not been fully studied. We examined the properties of the pure MTX "therapeutic segment," that period that begins with start of MTX and terminates when MTX is discontinued or another DMARD is added, by observational study. METHODS: We studied new MTX starts for the period 1988 through 1996 for 437 patients from a parent cohort of 4253 patients. Patients were drawn from 8 Arthritis, Rheumatism, and Aging Medical Information System (ARAMIS) data centers: 2 community based populations; 2 private rheumatological practices; 2 university referral practices; and 2 university clinics for underserved minority urban populations. Health Assessment Questionnaire (HAQ) Disability Index scores (0-3) were obtained prospectively each 6 months. RESULTS: At MTX start, patients had relatively long average disease duration of 16.7 years, and had moderately severe disability, with an initial HAQ mean disability score of 1.48. Over the 10 year period examined in the parent cohort of 4253 patients (and thus irrespective of therapy), the prevalence of MTX use rose from 19% to 45%, while mean HAQ disability declined from 1.34 to 1.11. This correspondence is consistent with an accrual of benefits from more frequent use of MTX and other DMARD over this period. The MTX therapeutic segment revealed a distinct shape. HAQ-Disability Index values began at 1.48 at baseline and declined to a maximal improvement of 1.23 at 30 months. This long period to maximum benefit may have been partly driven by a slow titration upward to an optimal dosage. After 42 months, disability for this population began to re-progress and reached 1.39 at 84 months, still below the pretreatment baseline. Re-progression to baseline was about 8 or more years. Cumulative disability averted with MTX treatment for this population was roughly 1.30 disability-unit-years. CONCLUSION: MTX treatment of RA in practice differs substantially from common perception and appears suboptimal by being too little, too late, and too long to treatment change. A modification of the "sawtooth strategy" in which the disease is "ratcheted down" by change of MTX therapy at 3 years or when re-progression has proceeded halfway to baseline, rather than waiting for return to baseline, is suggested by these data. Also suggested is the need for more rapid upward dosage titration and longer maintenance of an optimal or highest tolerated dosage. "Therapeutic segment" data provide insights into strategic approaches to management of RA since they allow estimation of population aggregate properties such as time to maximum benefit and the time to return to baseline.     

Drug Network Characteristics as a Predictor of Cessation of Drug Use Among Adult Injection Drug Users: A Prospective Study

Few studies have examined recovery from opiate and cocaine dependence without treatment, referred to as “natural recovery,” “spontaneous recovery,” and “spontaneous remission.” The present study examined the relationship between network characteristics and cessation of heroin, cocaine, and crack use in a sample of underclass inner-city injection drug users in Baltimore, Maryland. Participants were enrolled in an experimental human immunodeficiency virus (HIV) preventive intervention. Between the baseline and follow-up interviews, which averaged 5.2 months, 24 (7%) of 335 participants reported ceasing to use heroin, cocaine, and crack. Individuals who had reported cessation of drug use at follow-up had reported at baseline a smaller proportion of their network members with whom they used drugs (p <. 02). Using multiple logistic regression analyses and adjusting for baseline drug use, enrollment in drug treatment, and demographic and background variables, cessation of drug use was associated with a lower proportion of personal network members in one's drug network (odds ratio [OR] = 25.4, p. 05). The data from this study suggest that network members have potential for social influence on the cessation of drug use.     

Drug Injecting, AIDS, and Risk Behaviour: potential for change and intervention strategies

The sharing of unsterile needles and syringes is a primary means by which drug users who inject put themselves at risk of HIV infection. This paper examines a sample of 127 regular illicit drug users (both in and out of treatment) in terms of injecting and needle sharing patterns, and investigates the impact of concern about AIDS upon these behaviours. Amongst those that had ever injected, it was found that 54% had substantially reduced their risk behaviour, in that they either no longer injected, or else no longer shared injecting equipment. A further 32% had to some extent reduced their risk behaviour, and only 14% staled that they had been unaffected by concern about AIDS. Those who were in contact with agencies were more likely to have substantially reduced their risk behaviour than those not in contact with agencies. Regarding the impact of HIV testing, the data suggest that it may be associated with reduced rather than increased risk behaviours, though the differences only approach significance. In two consecutive time periods, similar proportions reported that they were still sharing; but by the second time period almost all reported some attempt at change. In general, the results confirm other studies, from the USA and Britain, that have shown that drug users are not inherently irrational, and are capable of modifying their risk behaviour. Availability of clean injecting equipment was given as the prime reason for sharing, and the free supply of needles and syringes is advocated as a complement to effective health education. Aggressive outreach work is to be encouraged so as to reach those individuals unlikely to use established schemes.     

The prevalence and incidence of sexually transmitted infections in a prospective cohort of injection drug users in Vancouver, British Columbia.

BACKGROUND: While several studies have reported on sexual risk behaviours and the prevalence of sexually transmitted infections (STIs) among injection drug users (IDUs), there are fewer prospective studies that have been able to examine populations of IDUs with no history of STIs. Therefore, the authors examined prevalence, correlates and factors associated with time to first STI infection in a prospective cohort of IDUs in Vancouver, British Columbia. METHODS: The authors examined the prevalence and correlates of STIs among IDUs at the time of recruitment into a prospective cohort study. The authors also evaluated the cumulative rate of time to first STI among IDUs with no history of STIs at baseline using the Kaplan-Meier method, and modelled factors independently associated with first STI using Cox regression. RESULTS: Between May 1996 and November 2003, 1560 individuals were recruited into the cohort; of these individuals, 745 reported a history of STI at baseline. Among the 815 who did not report an STI at baseline, 671 (82%) had at least one follow-up visit and were eligible for the analysis of time to first STI. After 36 months of follow-up, the cumulative rate of first STI was 8.2% for men and 15.9% for women (log-rank P<0.001), whereas the cumulative rate of first STI was 8.0% for IDUs who did not report sex trade involvement versus 19.8% for IDUs who reported sex trade involvement (log-rank P<0.001). In multivariate analyses, the risk of first STI remained independently associated with unprotected sex with regular partners (relative hazard=2.04, 95% CI 1.29 to 3.23; P=0.001) and unprotected sex with sex trade clients (relative hazard=2.36, 95% CI 1.46 to 3.82; P=0.005). CONCLUSIONS: In the present study, the authors found that STIs were associated with both regular sex partnerships and sex trade involvement. These findings are of particular concern because both unprotected sex with regular partners and sex trade involvement is common among IDUs. Interventions to encourage condom use among IDUs, particularly those with regular sex partners and those involved in the sex trade, should be further developed.     

Predictors of injection drug use cessation among Puerto Rican drug injectors in New York and Puerto Rico

More than half of all AIDS cases among Puerto Ricans have been attributed to injection drug use. Predictors of injection drug use cessation were examined among Puerto Rican injection drug users (IDUs) in New York and Puerto Rico. Analysis of baseline and 6-month follow-up data from 670 IDUs in NY and 316 in PR showed that 47% NY and 20% in PR reported cessation of injection at follow-up (p < .001). In multivariate analyses, having been in drug treatment since baseline was the only significant predictor of cessation for both sites (NY: AOR = 1.80; PR: AOR = 3.10). Increasing availability of methadone maintenance treatment, especially in PR, was indicated.     

Predictors of Injection Drug Use Cessation Among Puerto Rican Drug Injectors in New York and Puerto Rico

More than half of all AIDS cases among Puerto Ricans have been attributed to injection drug use. Predictors of injection drug use cessation were examined among Puerto Rican injection drug users (IDUs) in New York and Puerto Rico. Analysis of baseline and 6-month follow-up data from 670 IDUs in NY and 316 in PR showed that 47% NY and 20% in PR reported cessation of injection at follow-up (p < .001). In multivariate analyses, having been in drug treatment since baseline was the only significant predictor of cessation for both sites (NY: AOR = 1.80; PR: AOR = 3.10). Increasing availability of methadone maintenance treatment, especially in PR, was indicated.     

Sexual Adventurism, Substance Use, and High-Risk Sexual Behavior: A Structural Modeling Analysis of the Chicago MACS/Coping and Change Cohort

The purpose of this study was to model the relationships between dispositional tendencies towards sexual risk seeking (sexual adventurism) and engaging in risky behaviors (e.g., unprotected anal intercourse and recreational drug use). We analyzed data collected at semiannual assessments, between 1984 and 1993, from gay/bisexual participants in both the Chicago Multicenter AIDS Cohort Study (MACS) and the Coping and Change Study (CCS). Factor analysis on 34 items from the CCS questionnaires guided the construction of an index of sexual adventurism/risk-seeking which was then used in univariate and multivariate analyses to determine its relationship, across time, with the outcome behaviors of drug use and risky sex. Path analysis models then assessed the relative importance of sexual adventurism and drug use covariates for predicting risky sex in subsequent assessments. Sexual adventurism was significantly associated with both substance use and risky sex at all time periods. Multivariate analyses revealed this relationship to be independent of drug use; however, this was not true for the association between risky sex and drugs. Path analysis confirmed the causal links (either direct or mediated by drug use) between sexual adventurism and risky sex. Substance use had little, if any, direct association with high-risk sexual behavior when sexual adventurism was included in the models. These findings support the existence of a common underlying dispositional factor, sexual adventurism/risk seeking, that would be a major determinant of the association between risky sex and drug use among gay men. Similar findings from other studies indicate the wider potential applicability of sexual adventurism/risk-seeking measures and suggest the need for focused intervention efforts in targeting this subgroup of high-risk individuals.