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Parenteral drug abusers are at risk for acquired immunodeficiency syndrome (AIDS), which is caused by human immunodeficiency virus (HIV). We tested stored sera for antibody to HIV (anti-HIV) using two enzyme-linked immunosorbent assay (ELISA) methods and Western blot. The patients were parenteral drug abusers who had undergone percutaneous liver biopsy for chronic liver disease. Current or former alcohol abuse was noted in 88 (80%) of the 110 patients. The sensitivities of the two ELISA tests in comparison with Western blot, the more specific test for HIV, were 100 and 94%, respectively; the specificities were 94 and 99%. Western blot was positive in 36 (33%) of 110 patients. False-positive ELISA reactions for anti-HIV were seen in five (7%) of 70 patients with negative Western blot analyses. Compared to true-negatives, false-positives had significantly more years of alcohol abuse, younger ages of onset of alcohol abuse, greater frequencies of jaundice and edema, higher levels of alkaline phosphatase, total billirubin, total protein, and globulins, and lower levels of serum albumin. In a stepwise logistic regression, only hyperglobulinemia was significantly associated with a false-positive anti-HIV. We conclude that: (a) ELISA tests for anti-HIV are useful for screening abusers of alcohol and parenteral drugs with chronic liver disease for HIV infection, but positive results must be confirmed with more specific tests such as Western blot; (b) false-positive ELISA reactions in this population are associated with hyperglobulinemia; and (c) studies of HIV testing are needed in other populations of patients with alcoholism or liver disease.

Increasing mortality in intravenous (IV) drug users not reported to surveillance as acquired immunodeficiency syndrome (AIDS) has occurred in New York City coincident with the AIDS epidemic. From 1981 to 1986, narcotics-related deaths increased on average 32% per year from 492 in 1981 to 1996 in 1986. This increase included deaths from AIDS increasing from 0 to 905 and deaths from other causes, many of which were infectious diseases, increasing from 492 to 1091. Investigations of these deaths suggest a causal association with human immunodeficiency virus (HIV) infection. These deaths may represent a spectrum of HIV-related disease that has not been identified through AIDS surveillance and has resulted in a large underestimation of the impact of AIDS on IV drug users and blacks and Hispanics

Research on the epidemiology of HIV infection among IV drug users is still at a relatively early stage. Multilocation studies that would permit better geographic comparisons are greatly needed. Multi-method studies within single geographic areas are also needed to assess possible biases with respect to sample recruitment and data collection procedures. The continuation of the epidemic provides a changing historical context that complicates any comparisons. Despite these problems, there are some consistencies that can be seen across studies. Studies of HIV seroprevalence among IV drug users show wide variation among cities in the United States and Europe. The time that the virus was introduced into the IV drug using group within the city is one factor in explaining these differences; other cross-city factors have yet to be identified. Once HIV has been introduced into the IV drug use group within a particular geographic area, there is the possibility of rapid spread up to seroprevalence levels of 50% or greater. Thus, a currently low seroprevalence rate should not be seen as a stable situation. Frequency of injection and sharing of equipment with multiple other drug users (particularly at shooting galleries) have been frequently associated with HIV exposure. Being female, ethnicity (in the USA) and engaging in prostitution also may be associated with increased risk for HIV exposure, suggesting that prevention programs should include special consideration of sex and ethnic differences. Studies of AIDS risk reduction show that substantial proportions of IV drug users are changing their behavior to avoid exposure to HIV. This risk reduction is probably more advanced in New York, with its high seroprevalence and incidence of cases, but is also occurring in cities with lower seroprevalence and limited numbers of cases. The primary forms of risk reduction are increasing the use of sterile equipment, reducing the number of needle sharing partners, and reducing the frequency of injection. These behavior changes are very similar to the frequently identified behavioral risk factors associated with HIV exposure, suggesting that they should be effective in at least slowing the spread of HIV among IV drug users. No linkage of risk reduction to decreases in seroconversion has yet been shown, however, and greater risk reduction is clearly required. A variety of prevention strategies will probably be needed to reduce the spread of HIV among IV drug users. Prevention of initiation into drug injection is an undeniable long-term goal for the control of HIV infection, but there is very little research being conducted in this area.