Infections In Injection Drug Users Research Articles

Skin and Soft Tissue Infections in Injection Drug Users.

Skin and soft tissue infections (SSTIs) are common among injection drug users (IDUs). Subcutaneous and intramuscular injection ("skin-popping") and the injection of "speedballs" (a mixture of heroin and cocaine) are important risk factors for SSTIs in this patient population. Female IDUs appear to be at greater risk of SSTIs than male IDUs, probably because of more difficult venous access. There are conflicting data regarding the impact of HIV and human T-cell lymphotrophic virus II infection on the risk of SSTIs in IDUs; however, an expanding body of evidence suggests that immunosuppressive effects of the drugs themselves may play a role. Most information regarding the microbiology of SSTIs in IDUs comes from data on skin and subcutaneous abscesses, where Staphylococcus aureus and organisms that originate from the oral flora predominate. Clonal outbreaks and uncommon infections including tetanus, wound botulism, and a sepsis/myonecrosis syndrome due to Clostridium species have been recently reported in IDUs.

The changing epidemiology of HIV infection in injecting drug users in Dublin, Ireland.

Injecting drug users (IDUs) represent 41.6% of the total cohort of HIV-infected patients in Ireland. Between January 1999 and December 2000, referrals to the largest tertiary centre for HIV infection in Dublin have increased dramatically. This has occurred on a background of a reduction in the overall incidence of HIV infection in Ireland between 1990 and 1998. Here we describe the changing epidemiology of HIV disease in IDUs and explore potential aetiological factors. This is a retrospective study, collecting all data relating to new HIV diagnoses occurring in IDUs, referred to the GenitoUrinary Medicine and Infectious Diseases (GUIDE) clinic between 1987 and 2000. We calculated 6-month incidence rates of new HIV diagnoses in IDUs referred to the GUIDE clinic and performed a more detailed analysis of those patients diagnosed between January 1999 and December 2000, documenting age, sex, time and place of diagnosis, drug use history and primary drug of misuse, needle sharing history, attendance at a drug treatment clinic, prior HIV testing history, hepatitis B and hepatitis C status, and CD4 cell counts and HIV RNA levels at diagnosis. The number of new HIV diagnoses in IDUs increased fivefold between 1995 and 2000. Moreover, 40% of patients diagnosed since then have been under 22 years old. There has also been a significant reversal of the initial male to female ratio seen in the initial epidemic of the 1980s. There has been a significant increase in the incidence of HIV infection in IDUs between 1995 and 2000. Similar trends have been described recently in other risk groups. The aetiology of these trends is multifactorial, and a multidisciplinary, rejuvenated approach is required to focus on improving health education to reduce both sexual and needle sharing practices.

Risk factors of HIV infection and needle sharing among injecting drug users in Ho Chi Minh City, Vietnam.

We sought to identify risk factors for needle sharing and HIV infection among injecting drug users (IDUs) in Ho Chi Minh City (HCMC), Vietnam. Three cross-sectional surveys among IDUs, both on the street (in 11 urban districts) and in the rehabilitation center for IDUs in HCMC, were carried out in April of 1995, 1997, and 1998. Outreach workers interviewed IDUs about socio-demographic characteristics, drug use and sexual practices, and HIV knowledge and perceptions. The IDUs were also tested for seropositivity to HIV. Independent predictors for HIV positivity and needle sharing were determined by univariate and multivariate logistic regression for the study sample within the rehabilitation center in 1997 and for that on the street in 1998. The HIV prevalence in 1998 among IDUs was 44% for those on the street and 38.5% for those in the rehabilitation center. Independent predictors for HIV infection in IDUs were being injected by drug dealers (for the 1997 sample), injecting on the street, and sharing the drug pots (for the 1998 sample). The reported rate of needle sharing was low and decreased significantly from 20% in 1995 to 12% in 1998 for the sample of IDUs at the street. In the multivariate analysis, predictors for needle sharing for both study samples were injecting on the street, injecting at shooting galleries, and having shared needles in the past. Adequate and easy access to sterile needles and syringes, and a supportive environment of behavior change, especially in street and shooting gallery could reduce risks of virus transmission in the Vietnamese IDU community.

Treatment of hepatitis C infection in injection drug users

Chronic hepatitis C is the most common infectious disease among injection drug users (IDUs). Because of the allegedly poor compliance of IDUs with treatment requirements and conditions, hepatologists recommend treatment only if former IDUs have spent 6 to 12 months drug free. The aim of this prospective study was to investigate whether opiate-dependent IDUs with chronic hepatitis C virus (HCV) infection can be treated successfully with interferon. Eligibility for the study meant IDUs had to be HCV-RNA positive by polymerase chain reaction. Subsequently 50 inpatients were enrolled during detoxification treatment. HCV treatment was started with interferon alfa-2a (through 1998) or a combined regimen consisting of interferon alfa-2a and ribavirin (begun in 1998). All patients were treated and supervised by specialized physicians in both hepatology and addiction medicine. The end point for this study was defined as a loss of detectable serum HCV RNA at week 24 after treatment. The rate of sustained virologic response was 36%. Sustained response rates were not significantly different for patients who relapsed and returned to treatment (53%), relapsed and did not return to treatment (24%), or did not relapse (40%; P > .05). During the 24 weeks after treatment, we were unable to detect any reinfection, even among patients who injected heroin during this period. This surprising result should be examined in further studies. In conclusion, HCV-infected drug addicts with chronic HCV infection can be treated successfully with interferon alfa-2a and ribavirin if they are closely supervised by physicians specialized in both hepatology and addiction medicine. (HEPATOLOGY 2001;34:188-193.)

Suicide probability and psychological morbidity secondary to HIV infection: a control study of HIV-seropositive, hepatitis C virus (HCV)-seropositive and HIV/HCV-seronegative injecting drug users

Background: Suicide ideation and psychological morbidity among HIV-positive patients has been the object of intense research. No study has investigated this area among injecting drug users (IDUs) infected with HIV and those infected with the hepatitis C virus (HCV), which has the same patterns of transmission of the HIV and may favour HIV replication and, possibly, HIV disease progression. Methods: In order to examine the prevalence and characteristics of suicide ideation and psychological morbidity associated with HIV and HCV infection in IDUs, a sample of HIV+ ( n=81), HIV−/HCV+ ( n=62) and HIV−/HCV− ( n=152) subjects completed the Suicide Probability Scale (SPS), The Brief Symptom Inventory (BSI) and the Hospital Anxiety and Depression Scale (HADS). Results: No difference was found between the groups as far as the mean scores on SPS and the risk of suicide (no-low risk category: 70.7% HIV+, 56.09% HCV+, 65.6% HIV−/HCV−). Estimated psychological morbidity (BSI) (26.9% HIV+, 27.1% HCV+, 25.4% of HIV−/HCV−) and BSI and HADS scores were comparable across the groups. Conclusions: Suicide ideation, psychological morbidity and anxiety and depression symptoms seemed not to be directly influenced by HIV-serostatus. Careful assessment of psychological symptoms and suicide ideas among IDUs, as a vulnerable segment of population at risk of HIV and HCV infections, needs to be routinely carried out in clinical settings.

Sharing of drug preparation equipment as a risk factor for hepatitis C.

This study investigated the sharing of drug preparation equipment as a possible route of hepatitis C virus (HCV) transmission. HCV seroconversion was measured in a cohort of 317 injection drug users who tested negative for HCV antibody at recruitment. Cumulative HCV incidence was 16.7% per year. Among those who did not share syringes, HCV seroconversion was associated with sharing drug cookers and filtration cotton (adjusted risk ratio = 5.9; 95% confidence interval = 1.1, 31.7); 54% of HCV infections in injection drug users who did not share syringes were attributable to cooker/cotton sharing. Among injection drug users who do not share syringes, an important proportion of HCV infections may be attributed to cooker/cotton sharing.

Higher detection rate of hepatitis G and C virus RNA in liver tissue than in serum of deceased injection drug users.

To examine the prevalence of hepatitis G virus (HGV) and hepatitis C virus (HCV) infections in deceased injection drug users and for comparison of the detection rates of HGV and HCV RNA in liver tissue with detection rates in postmortem serum samples, RT-PCR was performed in 50 drug abuse-related fatalities. HGV RNA was detectable in liver tissue samples from 17/50 suddenly deceased drug abusers (34%). In 16 of these 17 positive cases, serum samples were also available but HGV RNA was detected in only 10. From 29/50 anti-HCV positive individuals, HCV RNA was detected in 23/50 liver tissue samples (46%), but HCV RNA was detectable in only 6/22 of the corresponding serum samples. In 12 anti-HCV positive cases (10 being also positive for HCV RNA in the liver), the examinations revealed a coinfection with HGV by detection of HGV RNA in the liver tissue samples. A significant association between the detection of HCV RNA in the liver and the occurrence of antibodies against the HCV NS4 protein, but not against HCV core antigen or NS3 protein was observed. The probability of anti-HCV and HCV RNA positivity increased with the age of the individuals. No HGV or HCV infection was detected in a control group of 50 persons who died suddenly by violent impact. The prevalence of active HCV and HGV infections in injection drug users detected by RT-PCR in liver tissue is in good accordance with data obtained from sera from living injection drug users. In contrast, the detection rate in postmortem serum samples was clearly lower. Possible reasons for this observation are discussed and the use of liver tissue for postmortem detection of hepatitis virus RNA is recommended.

Serum IgE Levels in Patients with Human Immunodeficiency Virus Infection

Increased serum IgE levels are associated with advanced HIV infection. The magnitude of the increase has varied greatly between studies which generally did not assess potential confounding factors. To determine whether the increased serum IgE levels reported with HIV infection is affected by demographic or behavioral factors, we studied injection drug users, women, and minority ethnic and racial groups with HIV infection, for whom little data now exist. A prospective cross-sectional study of ambulatory patients with or at risk for HIV infection was performed. We enrolled 83 injection drug users and 56 non-drug users seropositive for HIV and 43 seronegative at-risk individuals from an Infectious Diseases clinic and a longitudinal study of HIV infection in injection drug users in the Bronx, New York City. Fifteen HIV-seronegative non-atopic controls were also studied. Total serum IgE levels were measured by a solid phase fluorescent assay and lymphocyte phenotypes were measured by monoclonal antibodies. On multiple linear regression analysis, HIV infection (P=.01) and advanced HIV disease (P < or =.01) were independently associated with increased serum IgE levels, controlling for gender, race, age, and use of injection drugs. In both HIV-seronegative and seropositive individuals, female gender was independently associated with lower IgE levels (P < or = .001). We did not find an independent effect of race or injection drug use on IgE levels. Increased serum IgE levels were associated with HIV infection, the highest levels existing in those with advanced HIV disease. Women had lower IgE levels than men, independent of HIV status. Active or past drug use, race, and age were not found to be independently associated with serum IgE levels. Further studies are necessary to elucidate the mechanisms underlying the increased serum IgE levels seen with HIV infection and its associated immunodeficiency, and to substantiate and explore the decreased levels found in women.

Health care costs of a continuing epidemic of hepatitis C virus infection among injecting drug users.

To estimate the direct health care costs of a continuing epidemic of hepatitis C virus (HCV) infection among injecting drug users (IDUs) in Australia from the formal health care system's perspective. A Markov cohort model is used to map the disease paths of successive hypothetical cohorts of 1,000 patients as they develop the sequelae of HCV over an extended period of time. IDUs becoming infected with HCV. Estimates of the number of persons in each of a limited number of disease states are used in conjunction with direct medical costs associated with ambulatory visits and inpatient hospital admissions over the course of the disease to estimate the long-term impact on the health care system of HCV infection among successive cohorts of IDUs. For every 1,000 IDUs newly infected with hepatitis C in a given year, there is an implied $14.32 million in health care spending over the years as sequelae become manifest, with cumulative total costs of some $0.5 billion (1994 dollars) after 60 years as the costs of successive cohorts of HCV-infected IDUs are added to the prevalence pool. If the estimated 10,000 new HCV infections in IDUs in Australia per year continue for the next 60 years, total direct health care costs will be around $4 billion over that period. Efforts to prevent HIV transmission among IDUs have been shown to be clearly cost-effective. These data imply that there is an even more pressing need to halt or slow the current epidemic of HCV infection among IDUs on fiscal grounds alone.

Opiates and infection

This review on the effects of opiate use on infectious diseases discusses the complete spectrum of infections in the opiate user, including those of the lung, the GI tract, the skin, the skeletal system, and the CNS. There is both increased prevalence and increased severity of bacterial and viral infections in injection drug users with the outcome of increased morbidity and mortality. The experimental administration of opiates has lead to a greater understanding of the effects on susceptibility to and progression of infectious diseases. Animal models of opiate dependence and infection are reviewed with specific attention to cases in which the opiate-mediated effects are harmful and in which cases they are beneficial.

Opiate effects on in vitro human retroviral infection.

The transmission and progression of the human retroviruses HIV-1 and HTLV-1/2 can be most likely influenced by a variety of "lifestyle cofactors" which includes the use of certain injected pharmaceuticals. Some investigations have suggested that HIV-1 infected individuals who are injecting drug users (IDUs) may undergo an accelerated rate of progression to AIDS. It is known that opioid receptors exist on cells pertinent to immune function, and that the activation or inhibition of these receptors may enhance or down-regulate some cell activities. The mechanisms for these effects have not yet been elucidated, nor have the effects of opioids on retroviral infection models been fully determined. While some work has been performed on the effects of opiates on infection by HIV-1 and SIV virtually no work has been done on the potential effects of this class of drugs on HTLV-1 and 2 infection. The potential effects of opiates on these retroviruses are important because of the higher incidence of infection in IDUs. Because IDUs compose one of the emerging high risk populations for infection with HIV-1 and more recently HTLV it is relevant to analyze the direct and indirect effects of opioids on the progression of retroviral infections. Our preliminary results from in vitro syncytia formation studies suggest a modulation by opioid-selective receptor agonists of in vitro infection by both HIV-1 and HTLV-I. These initial results underscore the necessity for further studies to define and elucidate the role of opiate abuse in the infection by human retroviruses as well as the associated pathogenesis.

A sterile syringe for every drug user injection: how many injections take place annually, and how might pharmacists contribute to syringe distribution?

Our objectives were to estimate the annual number of injections by injection drug users (IDUs) in the United States of America, and to describe the potential role of pharmacists in providing IDUs with a sterile syringe for every injection. We estimated the number of annual injections by IDUs for the United States, selected U.S. states, and selected U.S. cities according to the following formula: number of injections per year = (number of IDUs) x (average number of injections per IDU per day) x 365. Data were obtained from published articles, personal communications with local experts, and selected national databases. We also reviewed published and unpublished studies of pharmacy kits, pharmacist attitudes, and pharmacist practices in the United States and abroad. Between 920 million and 1.7 billion injections by IDUs take place each year in the United States. We estimated 12 million injections per year in San Francisco and >80 million in New York City. A similar number of syringes would be needed to satisfy the goal of a sterile syringe for every injection. Pharmacy-based strategies, including the sale of kits for injection drug use, have provided sterile syringes to IDUs in Europe, Australia, and New Zealand. Modification of laws restricting syringe purchase and possession has led to marked increases in purchase of syringes from pharmacies and reductions in needle-sharing. In conclusion, large numbers of syringes would be required to provide a sterile syringe for every injection, but significant numbers of pharmacists seem to be willing to play a central role in syringe sale and distribution. Outreach programs should emphasize that using a sterile syringe for every injection is the optimal HIV prevention practice for IDUs who cannot or will not stop injecting. Pharmacy-based syringe sale or distribution has the potential to augment current efforts to prevent HIV infection in IDUs, their sex partners, and their children.

Validity of three measures of antisociality in predicting HIV risk behaviors in methadone-maintenance patients

Most opiate users are injection drug users (IDUs). A significant percentage of IDUs have antisocial personality disorder (APD). APD has been found by some researchers to be an additional risk factor for human immunodeficiency virus (HIV) infection in IDUs. The present study evaluated the association of sociodemographic characteristics, substance abuse history, and several measures of antisociality including the DSM-III-R diagnosis made by the Personality Disorder Examination, the California Psychological Inventory-Socialization Scale, and Hare's Revised Psychopathy Checklist, to behaviors associated with HIV risk in 289 opiate-dependent methadone-maintained subjects. The presence of drug- and sex-related risky behaviors measured by the Risk Assessment Battery was predicted more consistently by measures of personality traits associated with antisociality than by a diagnosis of APD.

A prospective study of syphilis and HIV infection among injection drug users receiving methadone in the Bronx, NY.

The purpose of this study was to assess the relationship between syphilis and human immunodeficiency virus (HIV) infection in injection drug users. A 6-year prospective study of 790 injection drug users receiving methadone maintenance treatment in the Bronx, NY, was conducted. Sixteen percent (4/25) of HIV-seroconverting patients, 4.8% (16/335) of prevalent HIV-seropositive patients, and 3.5% (15/430) of persistently HIV-seronegative patients was diagnosed with syphilis. Incidence rates for early syphilis (cases per 1000 person-years) were 15.9 for HIV-seroconverting patients, 8.9 for prevalent HIV-seropositive patients, and 2.9 for persistently HIV-seronegative patients. Early syphilis incidence was higher among women than men (8.4 vs 3.2 cases per 1000 person-years). Independent risks for early syphilis included multiple sex partners, HIV seroconversion, paid sex, and young age. All HIV seroconverters with syphilis were female. Diagnosis of syphilis in drug-using women reflects high-risk sexual activity and is associated with acquiring HIV infection. Interventions to reduce the risk of sexually acquired infections are urgently needed among female drug users.

Neurologic consequences of HTLV-II infection in injection-drug users

Several case reports have suggested an association between human T-cell lymphotropic virus type II (HTLV-II) infection and chronic neurologic disease. We performed serial neurologic examinations in injection-drug users (IDU), a group known to be at increased risk for HTLV-II infection. At baseline, those infected with HTLV-II alone, human immunodeficiency virus (HIV) alone, or both were significantly more likely to have neurologic disability than uninfected subjects. Longitudinally, HTLV-II infection was independently associated with the development of global neurologic disability and neuropathy, suggesting that HTLV-II causes neurologic disease.

Reduced risk of hepatitis B and hepatitis C among injection drug users in the Tacoma syringe exchange program.

This case-control study examined the association between syringe exchange use and hepatitis B and C in injection drug users. Case patients included 28 injection drug users with acute hepatitis B and 20 with acute hepatitis C reported to the health department in a sentinel hepatitis surveillance county; control subjects were injection drug users with no markers of exposure to hepatitis B or C (n = 38 and 26, respectively) attending health department services during the same period. Data were abstracted from clinic records. Seventy-five percent of case patients with hepatitis B and 26% of control subjects had never used the exchange; similar proportions were found for the hepatitis C case and control groups. After adjustment for demographic characteristics and duration of injecting drugs, nonuse of the exchange was associated with a sixfold greater risk of hepatitis B (odds ratio [OR] = 5.5; 95% confidence interval [CI] = 1.5, 20.4) and a sevenfold greater risk of hepatitis C (OR = 7.3; 95% CI = 1.6, 32.8). The results suggest that use of the exchange led to a significant reduction in hepatitis B and hepatitis C in the county and may have also prevented a substantial proportion of human immunodeficiency virus infections in injection drug users.

Predictors of HIV status among injecting drug users and health promotion.

Two consecutive samples one year apart of injecting drug users (n = 754 and n = 345) were collected in Sydney, Australia and analysed for predictors of Human Immunodeficiency Virus (HIV) prevalence. Data indicated that similar variables were associated with HIV infection in both waves of the study. Risks for HIV infection included number of injections in last typical using month, acceptance of used injecting equipment from other injecting drug users (IDUs) who were known to be infected either before or after the sharing occurred, having sex with people known to be infected with HIV, and sexual orientation. It was not possible to determine whether sexual or equipment sharing with known HIV infected people preceded or followed HIV infection. These data confirm that predictors of HIV prevalence in Sydney are similar to those found in overseas studies and that sexual orientation appears to be the most powerful predictor. These data suggest both that sexual contact is an important route of infection in IDUs, and that sexual risks for HIV infection in IDUs need to be emphasised.

The effects of methadone on immune function among injecting drug users: a review.

Methadone maintenance therapy is advocated as a major preventive strategy for the spread of the human immunodeficiency virus (HIV) and other blood-borne infectious agents among injecting drug users (IDUs) because of its effects in decreasing the frequency of injecting and presumably sharing of equipment. As an opioid agonist, methadone may share the direct and indirect immunoregulatory effects of other opioids, and thus affect susceptibility to, and the natural history of, HIV infection. Available evidence pertaining to methadone and immune function is reviewed. The long-term immunosuppression observed in heroin injectors on present (incomplete) evidence appears to be caused by factors associated with a drug-using lifestyle rather than by a direct action of heroin. Although data are conflicting, it is most likely that methadone does not significantly impair immune function and is safe for HIV-infected IDUs, possibly even allowing some improvement of immune function to occur. The increasing reliance placed on methadone maintenance to control the epidemic of HIV infection in IDUs requires that remaining uncertainties regarding methadone and immune function are clarified urgently.

Clinical manifestations and predictors of disease progression in drug users with human immunodeficiency virus infection.

To examine the clinical course of human immunodeficiency virus (HIV) infection in injection-drug users, we conducted a prospective study of a cohort of patients in a methadone-treatment program in New York City from July 1985 through December 1990. The patients underwent standardized evaluations at base line and semiannually thereafter and received on-site primary medical care. Rates of progression to the acquired immunodeficiency syndrome (AIDS) and major outcomes before the development of AIDS were examined by univariate analyses; the risk of AIDS was also assessed by product-limit survival analysis and proportional-hazards regression. Of 318 HIV-seropositive patients who did not yet have AIDS (171 men and 147 women), 90 were black, 179 were Hispanic, and 49 were white; the median age was 33 years. Over a median of 3.0 years of follow-up, 55 (17 percent) received a diagnosis of AIDS (incidence per 100 person-years, 5.8). Major outcomes before the development of AIDS included oral candidiasis (incidence per 100 person-years, 11.2), pyogenic bacterial infections including pneumonia and sepsis (8.0), pulmonary tuberculosis (1.2), multiple constitutional symptoms (13.6), and herpes zoster (1.3). There were 41 deaths from AIDS, and 13 seropositive patients without AIDS (4.1 percent) died of bacterial infections, as compared with only 1 of 411 seronegative patients studied (P < 0.001). The incidence of AIDS was 62 percent lower among those who took zidovudine than among those who did not (P = 0.02). In the multivariate analysis, progression to AIDS was best predicted by low numbers and percentages of CD4+ lymphocytes, nonuse of zidovudine, and the presence of oral candidiasis, bacterial infections, or tuberculosis. There was no consistent relation between progression to disease and the continued use of injection drugs. HIV-infected injection-drug users have progression to AIDS at rates comparable to those of other HIV-infected groups, but they have substantial pre-AIDS morbidity and mortality, particularly from bacterial infections, which also appear to predict disease progression.

Human T-Cell Lymphotrophic Virus in California's Injection Drug Users

Human T-cell lymphotrophic virus I (HTLV-I) and human T-cell lymphotrophic virus II (HTLV-II) are closely related retroviruses that are highly prevalent in injection drug users (IDUs). The bulk of infection in this group probably occurs with HTLV-II, with a lower prevalence of HTLV-I. HTLV-I is known to cause adult T-cell leukemia/lymphoma and tropical spastic paraparesis. HTLV-II has not been proven to cause any human pathology, but may be immunosuppressive and is almost indistinguishable serologically from HTLV-I. As with human immunodeficiency virus (HIV), infection with these viruses is likely to be lifelong and the disease may have a latent period of many years. Unlike HIV, HTLV-I and/or HTLV-II are not likely to be transmitted from mother to child prenatally, and usually require breast-feeding for vertical transmission. It is likely that HTLV-I and/or HTLV-II has been prevalent in IDUs for far longer than the HIV epidemic. HTLV-I and/or HTLV-II are relevant to the AIDS epidemic in that they may function as biologic markers of behavioral risk status for HIV infection in IDUs or their sexual partners, and they may accelerate the course of HIV infection in persons coinfected with HTLV-I and/or HTLV-II and HIV. Coinfection will be more likely as the HIV epidemic progresses. Pregnant addicts entering outpatient methadone maintenance treatment in San Francisco County or Contra Costa County during 1990 were found to have an HTLV-II prevalence of 21% (n = 24). Important issues in counseling infected methadone patients are described.