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OBJECTIVE: To describe the prevalence of hepatitis C virus (HCV) infection in a sample of homeless and impoverished adults and examine risk factors for HCV infection in the overall sample and as a function of injection drug use.
DESIGN: Assays were conducted on stored sera. Sociodemographic characteristics and risky sexual activity were measured by content-specific items. Substance use was measured by a structured questionnaire. HCV antibodies were tested by enzyme-linked immunosorbent assay; a confirmatory level was defined by recombinant immunoblot assay.
SETTINGS: Shelters ( N = 36) and outdoor locations in Los Angeles.
PARTICIPANTS: Eight hundred eighty-four homeless women and/or partners or friends.
RESULTS: Among this sample of 884 homeless and impoverished adults, 22% were found to be HCV infected. Lifetime injection drug users (IDUs) (cocaine, crack, and methamphetamine) and recent daily users of crack were more likely than nonusers or less-frequent users of these drugs to be HCV-infected. Similar results were found for those who had been hospitalized for a mental health problem. Among non–injection drug users and persons in the total sample, those who reported lifetime alcohol abuse were more likely than those who did not to be HCV infected. Controlling for sociodemographic characteristics, multiple logistic regression analyses revealed IDUs have over 25 times greater odds of having HCV infection than non-IDUs. HCV infection was also predicted by older age, having started living on one's own before the age of 18, and recent chronic alcohol use. Males and recent crack users had about one and a half times greater odds of HCV infection when compared to females and non–chronic crack users.
CONCLUSIONS: Targeted outreach for homeless women and their partners, including HCV testing coupled with referrals to HCV and substance abuse treatments, may be helpful.
Nationwide, hepatitis C virus (HCV) is a serious and rapidly emerging infectious disease that is on an equal par with HIV in terms of morbidity and prevalence. 1 To date, approximately 4 million Americans have been infected with HCV. 2 Recently, members of the California Senate reported HCV to be at epidemic proportions in California, with an estimated 500,000 residents already infected. Approximately 80% of individuals infected with HCV become chronic carriers of the virus, 3 and about 85% of infected individuals develop chronic liver disease. 1 Given the magnitude of affected individuals, scientists are now warning about a future epidemic of end-stage liver disease resulting from HCV infection. 3,4
Homeless persons are at high risk for HIV as a result of injection drug use, unprotected sexual activity, prostitution, and victimization. 5,6 Although the extent of HCV infection among homeless populations remains largely unknown, there is increasing suspicion that it is silently escalating among the homeless as risk factors for HCV, particularly injection drug use, overlap with those for HIV. 7 Studies conducted with homeless men and women have found that 73% to 80% report a lifetime history of drug use, with 13% to 20% involved in injection drug use. 8–10 Beyond drug use behaviors, over 70% of homeless adults report unprotected sex with multiple partners, 11 which may increase their risk for HCV infection. 12 Finally, many homeless individuals have histories of mental illness and incarceration, which have been demonstrated to be important considerations in evaluating risk for HCV infection. 13,14
In terms of risk behaviors, epidemiological studies show that injection drug use accounts for about 60% of all chronic and new HCV infections annually. 15 However, controversy exists about the number of HCV cases attributable to noninjection drug use and sexual transmission. Data from several studies indicate that the percentage of reported cases of HCV acquired through sexual exposure has tripled since 1990 to a high of 16%. 15 The highest sexual risks for HCV infection appear to be having sex with multiple partners and traumatic sex that results in blood exchange. 16 Research regarding HCV transmission in relation to other documented risk behaviors; such as noninjection drug use (e.g., inhaled cocaine, and methamphetamine) 17 is advancing. Alcohol abusers have also been found to be at increased risk in some studies in which no other risk factors existed. 18 However, other studies found alcohol users to be at greater risk only in the presence of injection drug use. 19
Aside from the identification of HCV risk factors, it is important to consider how these risk factors vary among different vulnerable populations. Diaz et al. 13 demonstrated that, even among injection drug users (IDUs), important variations in patterns of HCV infection exist. In this context, therefore, analysis of the population-specific risk factors present in a homeless group becomes critical. To date, research regarding HCV in homeless populations in the United States is very limited, and there are no published accounts specifically addressing HCV infection among injecting and noninjecting homeless women and their intimate partners.
In this study, we describe the prevalence of HCV in a sample of homeless and impoverished adults and examine risk factors for HCV infection. Analysis of risk factors is presented for the overall sample, as well as for IDUs and non-IDUs as separate subsamples.
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Within our sample of 884 homeless and impoverished adults in Los Angeles, our findings revealed that 22% were HCV infected. Lifetime injection drug use and age were clearly associated with HCV antibody positivity among the total sample. Recent daily use of alcohol and possibly crack also significantly increased the chances of being HCV antibody positive, but to a much lesser degree.
Important similarities and differences were shown between respondents with and without histories of injection drug use, thus corroborating results of past research and highlighting the extreme importance of this risk factor. Injection drug use has been repeatedly identified as the predominant current risk factor for HCV infection in the United States, and it has been postulated that HCV may be endemic in IDU populations. 29 The 77% HCV seroprevalance rate in the IDU subsample (as opposed to 12% in the non-IDU group) corresponds with the 60% to 90% range reported in other injection drug use prevalence studies. 13 Moreover, several studies have documented that needle exchange programs can be an effective part of a comprehensive strategy to reduce the incidence of blood-borne virus transmission. 15 This study reaffirms the importance of assessing injection drug use behaviors when working with homeless populations.
Apart from injection drug use, in unadjusted analyses, lifetime cocaine, crack, and methamphetamine use and recent chronic crack use also proved to be significant drug-related HCV risk factors in the total sample. In reporting non-IDU drug behaviors as HCV risk factors, it is important to consider their potentially associated mechanisms of transmission such as cocaine use via intranasal delivery 29 or crack use, which may facilitate HCV transmission because of oral lesions developed from smoking. 30 However, these findings may reflect the difficulty of assessing past and present injection drug use among any population and the fact that even brief exposure to blood, such as through even a few episodes of injection drug use activity, may be sufficient to transmit HCV. Thus, it is possible that the relationships found with non-IDUs are confounded by unreported injection drug use.
Since all of the specific lifetime drug use factors became nonsignificant when injection drug use was controlled, it appears that their effects in this sample resulted from use by injection. This study did not evaluate whether the people shared drug preparation equipment, including cookers and/or filtration cotton; however, it is likely that sharing of equipment may have occurred, given the lack of resources and frequently communal nature of many homeless groups. Interestingly, recent chronic crack use was a significant predictor of HCV infection in the regression model for IDUs alone, and appeared to play some role in HCV infection for the sample as a whole. Thus, continued investigation is warranted.
The relationship found between alcohol use and HCV antibody positivity is quite interesting, and perhaps somewhat ominous. Why lifetime alcohol abuse, and especially recent daily alcohol use, were significantly related to HCV antibody positivity in the non-IDU group and not in the IDU group is unclear; however, it may demonstrate the drug preferences of each group or just the overwhelming effect of injecting drugs.
Regarding HCV transmission through unprotected sex, past research results have been inconsistent, precluding convincing evidence of trends. In this study, as in some others, 31,32 no pattern of risk associated with sexual behaviors was demonstrated. The finding that homeless individuals with more than 3 recent sexual partners had extremely low odds of HCV infection compared to those with fewer sexual partners in the past 6 months was unexpected, but supported our findings that having multiple partners was positively associated with frequency of condom use among homeless persons. It is also possible that HCV could have been transmitted during lifetime sexual activity. Thus, the extent to which HCV is sexually transmissible remains an important concern given that the epidemic could spread outside currently identified risk groups by this route. 32 Hence, sexual transmission 33 as well as other potential modes of transmission, such as sharing of toothbrushes, razors, etc., should be investigated. 32,34
Similar to other reports in the literature, 32,35 our findings revealed greatly increased risk for HCV infection when a partner or friend was either HCV infected or reported injection drug use. While sexual transmission was not supported in our findings, or in those of other researchers, 32,35 other studies have found evidence that higher rates of HCV transmission occur between spouses than in the general population. 33,36
Only 12 of the 884 participants (1.4%) were found to be HIV infected, and of these, 4 were both HIV and HCV infected. This seemingly low prevalence of HIV among at risk homeless women has been corroborated in previous studies of homeless men and women both in the Los Angeles area 37 and nationwide, 38 and provides evidence that education and prevention continue to be important strategies to employ. While the presence of HIV infection has been found to correlate with HCV infection in heterosexual couples, 36 the low prevalence of HIV among the homeless and impoverished adults in Los Angeles may explain the fact that a relatively small number of HCV-infected participants were also HIV infected.
Because we do not have data on the subjects' liver enzyme measurements, HCV polymerase chain reaction quantification, or liver biopsy results, we cannot describe the extent of active disease. However, data show that almost all HCV-infected persons develop chronic infection. 15,39 Experts suggest that the majority of chronically ill infected persons develop HCV-related hepatic abnormalities and that as many as 20% of the chronically infected develop cirrhosis.
This study demonstrates that a history of mental health problems serious enough to warrant hospitalization is important to consider in evaluating HCV risk. This finding corroborates research by Rosenberg et al. 14 and others 40 who investigated HCV prevalence rates among patients under treatment for serious mental illness. Much remains to be learned about the relationship between mental health and HCV, because it has not been thoroughly addressed in past research on the epidemiology of HCV.
Although involvement with injection drug use or injection drug–using partners probably contributes significantly to transmission of HCV infection among the mentally ill, it is clear that the risks for HCV infection in this population are compounded. Given the high rates of HCV infection among persons with serious mental illness, the development of HCV prevention and screening programs targeted toward the mentally ill appears to be both timely and justified.
While this study provides strong evidence that HCV infection is widespread in this urban homeless population, replication in other homeless populations is necessary. The limitations of this study include the self-report nature of the behavioral risk factors and the utilization of a convenience sample for HCV testing. Underreporting of injection drug use is of particular concern. Reluctance to divulge illegal behavior has been reported in the literature, 41 and has been attributed to factors such as self-image issues, concerns about legal risk, and fear of losing shelter residence. 41,42 However, we have found that when interviewers from the community develop rapport with respondents early in the interview process, and trust and confidentiality are emphasized, underreporting becomes less of a problem. For example, we found a relatively high level of concordance (76%) between objective hair analysis and self-report of cocaine use among homeless women in a previous study. 42 Finally, because the sample was drawn from an urban center in California, the findings of this study may not be generalizable to other populations of homeless individuals and/or homeless couples who reside in different parts of the country and whose behaviors may be more characteristically region specific.
Several policy implications can be drawn from this study. First, resource allocation for HCV education and prevention should include money targeted toward homeless populations. In 1998, the Centers for Disease Control and Prevention called for HCV testing of persons in settings with potentially high proportions of IDUs, including correctional institutions, HIV counseling and testing sites, or drug and STD treatment programs. Locations where homeless people congregate should be included in this list. Homeless drop-in centers, soup kitchens, food pantries, shelters, and street outreach using mobile units could be effective settings for HCV testing and education. Additionally, mental health centers whose clients include homeless people should be more aggressive in testing for possible HCV infection. Ideally, HCV testing programs in these settings should include counseling and referral or arrangements for medical management. Targeted outreach for homeless women and their partners, including HCV testing coupled with referrals to HCV and substance abuse treatments, may be useful. In particular, clinicians should recommend HCV testing if clients disclose any known risk factors, such as previous injection drug use, sharing of needles and/or drug preparation equipment, or blood transfusion prior to 1992. Further, information about the dangers of continued alcohol use, as well as treatment with interferon and other approved drugs for HCV infection, may impede and/or delay the development of liver disease. Hepatitis A virus and hepatitis B virus immunization for HCV-infected persons is important for clinicians to consider and should be offered.
In making recommendations for future research, continued investigation and comparison of HCV risk factors between and across populations in differing environments would be warranted. Understanding population-specific predictors of HCV infection will facilitate the provision of appropriate and relevant health services and risk reduction activities.