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Biomedical subjects

D Vlahov

Publications and source records attributed to D Vlahov.

At least 217 records · Page 12Linked to original sources
PubMed1995

Age, gender, and other predictors of the wasting syndrome among HIV-1-infected injecting drug users.

We conducted a study to identify predictors of the wasting syndrome among human immunodeficiency virus 1 (HIV-1)-seropositive injecting drug users. We enrolled 113 cases (defined as an unexplained loss of > 10% baseline weight) and 226 controls (defined as < 5% weight loss or any weight gain) from a HIV-1-seropositive cohort of injecting drug users (N = 630) into a nested case-control study. Crude predictors of wasting included: older age [odds ratio (OR) for a 1-year difference = 1.06], female gender (OR = 1.66), more years spent injecting drugs (OR for 1-year difference = 1.05), presence of diarrhea (OR = 3.78), lower percentage of CD4 T-lymphocytes (OR for 10-unit difference = 0.73), and higher log beta 2-microglobulin concentration (OR for 1 log difference = 11.3). After adjusting for CD4 cell level, beta 2-microglobulin concentration, diarrhea, gender, length and frequency of drug use, age, the presence of thrush, and education, independent predictors of weight loss in HIV-seropositive injecting drug users were female gender (OR = 2.23) and increasing age (OR for 1-year difference = 1.06). Frequency and duration of drug use were not strongly associated with the odds of developing wasting syndrome in this HIV-1-seropositive cohort. These data indicate that HIV wasting syndrome in injecting drug users is distinct from complications of drug use.

Adult↗
PubMed1995

Clinical characteristics and prognostic value of acute retroviral syndrome among injecting drug users. Italian Seroconversion Study.

OBJECTIVE: To estimate the frequency of acute retroviral syndrome associated with HIV infection among injecting drug users (IDU), and to determine the extent to which acute retroviral syndrome predicts a faster rate of progression to AIDS and immunosuppression in this population. DESIGN: Prospective study of HIV seroconverters (median follow-up, 50.5 months). SETTING: Sixteen clinical centres throughout Italy established to study the natural history of HIV infection. PATIENTS: Three hundred and ninety-one IDU for whom the date of HIV seroconversion was established with a 9-month precision. MAIN OUTCOME MEASURES AND METHODS: Incidence of acute retroviral syndrome with signs and symptoms that included fever (temperature > 38 degrees C) occurring within 6 months prior to the time of first positive HIV test, progression to AIDS, crude and adjusted relative hazard of AIDS using survival analysis techniques, and trajectories of CD4+ cell counts using a piece-wise linear regression model incorporating the degree of dependency of within-person measurements. RESULTS: Of 391 HIV seroconverters, 39 (10.0%) were diagnosed with acute retroviral syndrome. During follow-up, 13 seroconverters with acute retroviral syndrome and 24 asymptomatic seroconverters developed AIDS. The Kaplan-Meier estimates for the cumulative AIDS incidence during 4.5 years of follow-up were 26.8 and 6.5%, respectively; the relative hazard of developing AIDS for acute retroviral syndrome was 5.59 (95% confidence interval, 2.79-11.20) after adjustment for age, sex and year of seroconversion. Although CD4+ level within the first year from seroconversion was similar, the rate of CD4+ cell decline after 1 year from seroconversion was faster in individuals with acute retroviral syndrome than in those without this syndrome (P < 0.001). CONCLUSIONS: Among HIV-infected IDU, a distinct acute retroviral syndrome is apparent and associated with a faster rate of clinical progression to AIDS and HIV-related immunosuppression.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Correlates of hepatitis C virus infections among injection drug users.

Injection drug users are at high risk for hepatitis C virus (HCV) infection. In Baltimore, Maryland, the prevalence of anti-HCV is greater among injection drug users who are black, human immunodeficiency virus (HIV) infected, have injected longer, have injected more frequently, and have injected cocaine than among other injection drug users. HCV infection occurs quickly after the initiation of injecting illicit drugs, with 78% of study participants anti-HCV positive after 2 years of injecting. The prevalence of anti-HCV among injection drug users does not appear to be related to socioeconomic factors or sexual practices. Some injection drug users remain free of anti-HCV even after years of injecting and serologic evidence of other bloodborne pathogens. Some of these injection drug users have HCV infection, demonstrated by HCV RNA in their sera. However, the basis for viral persistence in the absence of anti-HCV and for the absence of HCV infection in long-term drug users is not known. Further studies are indicated to determine the mechanism or mechanisms for the absence of anti-HCV in persons exposed to the virus, because the biologic basis for this condition may elucidate the elements missing in the immune response of the majority of HCV-exposed persons who acquire persistent infection. In addition, interventions to prevent HCV infections should be applied in populations at risk for injection drug use early or before drug use begins.

Adolescent↗
PubMed1995

Geographic variation in HIV infection among injecting drug users with Barcelona.

In response to a high incidence of AIDS among injecting drug users in Barcelona, Spain, the city established a program in four geographically distinct centers for assistance and surveillance. The centers provided testing, counseling, and monitoring of infectious diseases. In 1991-92, HIV rates were 33% in the northwest center, 39% in the western center, 39% in the east, and 71% in the south. Differences between the rates in the southern center when compared with those in the other centers were very significant (P < or = .001). These data show geographic variation of HIV infection within one city and substantiate the need to provide expanded medical care in the drug misuse treatment setting.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Normative data for a brief neuropsychologic test battery in a cohort of injecting drug users.

Recent epidemiologic studies of the cognitive performance of injecting drug users have demonstrated the need to establish appropriate test norms for this population. This report provides normative data from a group of 150 injecting drug users on a battery of standardized tests of cognitive performance stratified by age group (range 20 to 49 years) and educational level (mean 11.6, standard deviation 2.0). The analysis also includes estimation of partial correlations between neuropsychologic test scores and age and education. The analysis demonstrates that age and education are important determinants of performance for several of these tests, and provides norms that may be of use as a reference for clinical evaluation and research in drug user populations.

AIDS Dementia Complex↗
PubMed1994

Voluntary testing for human immunodeficiency virus (HIV) in a prison population with a high prevalence of HIV.

This study evaluated voluntary testing for human immunodeficiency virus (HIV) in a prison population with a high HIV seroprevalence. Data on demographic variables and participation in voluntary testing were linked to a blinded HIV serosurvey of consecutive Maryland prison entrants (April-July 1991). Among 2,842 entrants, HIV seroprevalence was 8.5% (men, 7.9%; women, 15.3%). Voluntary testing was accepted by 47% of the entrants, and it identified 34% of the HIV-seropositive inmates detected by serosurvey. Refusers of testing were more likely to test HIV-seropositive than were accepters (adjusted odds ratio (OR) = 1.84, 95% confidence interval (CI) 1.58-2.16). Refusers and accepters of testing had similar risk factors for HIV infection, chiefly current syphilis infection (adjusted OR = 5.96, 95% CI 3.15-10.27) and prior injected drug use (adjusted OR = 4.26, 95% CI 3.15-5.76). Among 100 entrants asked why they refused testing, primary reasons given included low risk of HIV, fear of testing HIV-seropositive, and lack of interest. Voluntary testing appears only moderately successful in identifying HIV-seropositive inmates in a high-seroprevalence prison population. However, the alternative, mandatory HIV testing of prisoners, can be construed as discriminatory and unethical when similar screening is not imposed on the population at large. Data presented here suggest strategies to improve acceptance of voluntary testing, especially by high risk inmates.

Adult↗
PubMed1994

Direct comparison of the relationship between clinical outcome and change in CD4+ lymphocytes in human immunodeficiency virus-positive homosexual men and injecting drug users.

BACKGROUND AND METHODS: To compare rates of decline of CD4+ lymphocytes among human immunodeficiency virus-positive homosexual men and injecting drug users, we followed up prevalent human immunodeficiency virus-positive homosexual men and current or former injecting drug users from February 1988 through August 1991. Subjects were free of acquired immunodeficiency syndrome at study entry and had semiannual clinical and laboratory evaluation, including measurement of T-cell subsets, under common protocols. Initial levels and rates of change of CD4+ lymphocyte counts were compared according to cohort membership and clinical progression, defined by the development of thrush or an acquired immunodeficiency syndrome--defining illness. Median follow-up was 30 months for both cohorts. RESULTS: At study entry, homosexual men had lower absolute numbers of circulating CD4+ lymphocytes than did injecting drug users (459/microL [0.46 x 10(9)/L] vs 509/microL, respectively). During follow-up, homosexual men exhibited a faster decline in CD4+ lymphocyte counts as well as more frequent development of HIV-related symptoms (thrush or acquired immunodeficiency syndrome). In both cohorts, initial levels of CD4+ lymphocytes and rates of decline in these cells were strongly associated with progression of disease, defined as remaining asymptomatic, onset of thrush, or onset of acquired immunodeficiency syndrome. Once homosexual men and injecting drug users were stratified by disease progression, their initial levels and rates of decline of CD4+ lymphocyte counts were similar. Thus, crude differences between the two study groups largely resulted from differences in development of clinical symptoms. CONCLUSIONS: In these cohorts of homosexual men and injecting drug users, clinical outcome was much more important than risk group membership in determining changes in CD4+ lymphocyte numbers. The close similarity between the groups also suggests that drug use, ethnicity, and socioeconomic status play a minor role in the progression of human immunodeficiency virus infection.

Adult↗
PubMed1994

My place, your place, and no place: behavior settings as a risk factor for HIV-related injection practices of drug users in Baltimore, Maryland.

Information is sparse on the social context of illicit drug injection behaviors and their relationship to HIV infection. This study examined relationships between injection settings, injecting with others, and HIV risk behaviors of sharing needles and not cleaning contaminated needles in a sample of 630 inner-city injecting drug users in Baltimore, MD. Through open-ended interviews, five primary settings of injection behavior were identified. These settings included one's own, friends' and mother's residence, shooting galleries, and semipublic areas. Most participants reported injecting in their own residence (92%) and friends' residence (86%) in the prior 6 months. In a multiple regression analysis, injecting at friends' residence, in shooting galleries, and in semipublic areas and frequency of injecting with others were significantly associated with frequency of sharing uncleaned needles, "slipping" (i.e., failure to disinfect shared needles), and not always cleaning used needles before injecting. Results suggest that interventions may benefit from targeting settings as well as behaviors to reduce the spread of HIV.

Adult↗
PubMed1994

Correlates of attitudes concerning human immunodeficiency virus and acquired immunodeficiency syndrome among hospital workers.

BACKGROUND: Correlates of attitudes related to HIV and AIDS for both clinical and nonclinical support hospital workers have not been well described. METHODS: A cross-sectional study was conducted among employees of an acute care, inner-city hospital to assess attitudes related to HIV and AIDS. RESULTS: A 51% response rate was obtained, with completed questionnaires obtained from 321 clinical workers and 245 nonclinical workers. The proportions tolerant of patients with HIV infection were 83% and 78%, respectively. Factors associated with a tolerant attitude in clinical workers included personally knowing someone with AIDS, high scores on general AIDS knowledge, high knowledge scores on modes of transmission, low levels of fear, and accurate perceptions of occupational risk. In nonclinical workers, factors associated with tolerance included having been tested for HIV, personally knowing someone with AIDS, accurate perceptions of occupational risk, low levels of fear, high scores on general AIDS knowledge, and high knowledge scores on modes of transmission. CONCLUSIONS: Although the study was cross-sectional, the data suggest potentially modifiable factors associated with AIDS-related attitudes. These factors may be amenable to intervention among both clinical and nonclinical support hospital employees.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Low power? Use two-dimensional confidence regions as a graphical method for depicting uncertainty.

Prospective studies of rare outcomes, such as HIV seroconversion or obsessive-compulsive disorder, can often result in small sample sizes with limited power for detecting associations. For this reason, it is useful to develop graphical procedures that enable researchers to depict uncertainty around parameter estimates and examine the direction of association when statistical power is low. Classical procedures include the reporting of confidence intervals, which typically are derived from asymptotic normality of parameters estimated using large samples. In this paper, we present a likelihood-based procedure for the estimation of the confidence region of two parameters from a conditional logistic regression of a nested case-control study with a relatively small number of cases. Graphical depiction of the confidence regions provides an easily comprehensible procedure to quantify the uncertainty of the estimation based on small samples.

Adult↗
PubMed1994

Suspected determinants of enrollment into detoxification and methadone maintenance treatment among injecting drug users.

Our primary aim in this study has been to evaluate selected conditions thought to influence the entry of injecting drug users (IDU) into detoxification and methadone maintenance programs, making use of a prospective study design to strengthen a cross-sectional investigation of these conditions. To begin our investigation, we analyzed cross-sectionally gathered data on 2879 IDUs who had been recruited through extensive community outreach efforts and who were interviewed at the time of recruitment. We then tested our hypotheses about suspected determinants of entry into treatment by analyzing prospectively gathered data on 1039 active drug users who had no recent history of being treated for drug problems. Among these 1039 IDUs (a subset of the initial cross-sectional sample), 144 entered a detoxification program between their recruitment interview and their next follow-up interview, conducted about six months after recruitment (range: 3.5-9.5 months) and 64 entered a methadone maintenance program during that observation interval. Using multiple logistic regression analyses, we found that a recent drug overdose, relatively higher frequency of injecting drugs, and a history of prior arrest or treatment were independent predictors of entry into detoxification. Being married or living with a partner, being female, a lengthy duration of drug use (> 10 years), and a history of prior treatment were independent predictors of entry into methadone maintenance. These findings shed light on what appears to be a different profile of suspected determinants of entry into a detoxification treatment versus methadone maintenance treatment, and help to clarify some potential differences between treated and untreated drug users that ought to be considered when evaluating results of investigations with IDU participants recruited solely from treatment settings.

Adolescent↗
PubMed1994

Myocarditis and cardiotropic viral infection associated with severe left ventricular dysfunction in late-stage infection with human immunodeficiency virus.

OBJECTIVES: The purpose of this study was to characterize the histologic and immunopathologic results of 37 endomyocardial biopsy samples from patients infected with human immunodeficiency virus type 1 (HIV-1) who were evaluated for unexplained global left ventricular dysfunction. BACKGROUND: Recent studies have identified a growing number of patients infected with HIV-1 who develop unexplained left ventricular dysfunction and congestive heart failure. Myocarditis has been confirmed at autopsy in small numbers of such patients, although a pathogenic opportunistic infectious agent can rarely be identified. METHODS: All patients had moderate to severe global left ventricular hypokinesia on two-dimensional echocardiography. Endomyocardial biopsy samples were evaluated by standard histologic studies, immunoperoxidase staining and in situ hybridization for cytomegalovirus and HIV-1 gene sequences. RESULTS: Twenty-eight patients presented with New York Heart Association functional class III or IV congestive heart failure. Four patients had myocarditis secondary to known etiologies (opportunistic infection n = 2; drug-induced hypersensitivity myocarditis n = 2). Of the remaining 33 samples, 17 (51%) showed histologic evidence of idiopathic active or borderline myocarditis. Immunohistologic findings revealed induced expression of major histocompatibility class I antigen on myocytes and increased numbers of infiltrating CD8+ T lymphocytes. Specific hybridization within myocytes was observed in 5 of 33 samples with the HIV-1 antisense riboprobe and in 16 of 33 samples with the cytomegalovirus immediate early (IE-2) antisense riboprobe. All but one patient with specific myocyte hybridization presented with congestive heart failure; all patients had myocarditis and CD4+ cell counts < 100/mm3. CONCLUSIONS: This study demonstrates that cardiotropic virus infection and myocarditis may be important in the pathogenesis of symptomatic HIV-associated cardiomyopathy.

AIDS-Related Opportunistic Infections↗
PubMed1994

Comparison of self-reported injection frequencies for past 30 days and 6 months among intravenous drug users.

In this study we compared two parallel self-reported measures that now are being used to assess the recent frequency of intravenous drug use. This study sample consisted of 926 HIV seronegative drug users recruited for participation in HIV research. During a standard interview with each drug user, we first asked about injections in the past 30 days, and then about injections in the past 6 months. The correlation between reports on the past 6 months and the past 30 days was appreciable when all injections were considered (Spearman correlation coefficient rho = 0.78). It increased when the sample was restricted to subjects who reported injections in the past month (rho = 0.88). This restriction resulted in a 15% reduction of the sample size, since 137 participants reported drug use in the previous 6 months but not in the previous 30 days. Concordance tended to be slightly higher for reported frequencies of heroin injections than for cocaine injections, and for men as compared to women. The observed levels of concordance indicate that in many instances both approaches can yield comparable results. Nevertheless the choice of 30 days recall vs 6 months recall must rest upon the specific research questions of each investigation.

Adult↗
PubMed1994

Maturity of human immunodeficiency virus infection and incubation period of acquired immunodeficiency syndrome in injecting drug users.

This study was aimed at estimating the maturity of the human immunodeficiency virus (HIV) epidemic in cohorts of injecting drug users with existing HIV infection at the time of first observation, and using this information to estimate the incubation period of acquired immunodeficiency syndrome (AIDS) in this population group. The method imputed the "missing" time from seroconversion to first observation for seroprevalent subjects in a combined cohort including injecting drug users from New York (n = 246) and Baltimore (n = 621). Imputation relied on a probability model predicting time since seroconversion on the basis of two markers of maturity of HIV infection: percent of CD4+ lymphocytes and platelet count. The model was developed from data observed in a combined cohort of subjects from New York (n = 24) and Baltimore (n = 112) who had incident HIV infections. The estimates of median time since seroconversion for the Baltimore and Bronx seroprevalent subcohorts were 28 and 39 months, respectively. The total time from seroconversion to AIDS was then estimated for the incident plus completed-prevalent cohorts using a modified version of the nonparametric product-limit method. The results showed that approximately 95% (95% confidence interval: 90 to 98%) of drug users remained AIDS-free 2 years after seroconversion; 83% (74-91%), 4 years after seroconversion; and 72% (61-82%), 6 years after seroconversion. Median time to AIDS was 10.2 years, with an estimated 95% confidence interval of 7.9 to 12.3 years. Consistency of these results with those derived from large cohorts of homosexual men indicate that the HIV incubation distributions for drug users and homosexual men are similar.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Temporal association between implementation of universal precautions and a sustained, progressive decrease in percutaneous exposures to blood.

To evaluate whether implementation of universal precautions was temporally associated with a decrease in reported parenteral exposures to blood, we analyzed data on self-reported parenteral injuries that were prospectively collected at the Clinical Center, National Institutes of Health (Bethesda, MD), from 1985 through 1991. We also assessed whether implementation of universal precautions, in concert with initiation of a program of postexposure chemoprophylaxis with zidovudine, was associated with decreased time to reporting of occupational exposures. Our data, possibly confounded by the occurrence of an occupational infection due to human immunodeficiency virus infection in 1988, nonetheless demonstrate a temporal association between a progressive, significant decrease in percutaneous injuries and the implementation of universal precautions that has been sustained through subsequent years. The analysis remains significant, regardless of the surrogate denominator chosen for analysis. No trend toward more rapid reporting of exposures was identified. Implementation of universal precautions appears to have contributed to decreased parenteral injuries in our hospital but did not affect reporting efficiency.

Blood-Borne Pathogens↗