title: Prevalence, patterns, and course of past hepatitis B virus infection in intravenous drug users with HIV-1 infection.
abstract: OBJECTIVE
  Hepatitis B virus (HBV) and human immunodeficiency virus (HIV) share common routes of transmission. Therefore, markers of either active or past HBV infection are present in many HIV-infected patients, particularly in intravenous drug users (IDUs). The aim of this study was to analyze the serological pattern of past HBV infection (presence or absence of anti-HBs) and the course of past HBV infection (changes in anti-HBs status, and HBV reactivation) in two cohorts of IDUs with and without HIV infection.
  
  
  METHODS
  HBV serum markers were studied in 388 HIV-positive and 197 HIV-negative IDUs. Among them, 263 HIV-positive and 50 HIV-negative patients with past HBV infection (serum HBsAg negative and anti-HBc positive, with or without anti-HBs) were followed-up for a median of 21 and 13 months, respectively, to detect changes in anti-HBs status and HBV reactivation.
  
  
  RESULTS
  The prevalence of HBV infection (either active or past) was higher in HIV-positive than in HIV-negative cases (90% vs 62%, p < 0.001), even when stratified by years of drug use. Most cases (92% of HIV-positive and 89% of HIV-negative) had markers of past infection. Among those patients with past HBV infection, 60% of HIV-positive and 72% of HIV-negative presented serum anti-HBs (p = 0.03). The incidence of anti-HBs loss was 1.8 cases/100 person-year in HIV-positive, and 1.8 cases/100 person-year in HIV-negative patients (RR 1.0, 95% CI 0.1-94, p = NS). Incidence of anti-HBs development was 17.6 cases/100 person-year in HIV-positive and 25.6 cases/100 person-year in HIV-negative IDUs (RR, 1.5, 95% CI, 0.6-3.5, p = NS). Only one HIV-positive patient with markers of past HBV infection developed an active infection (0.2 events/100 person-year).
  
  
  CONCLUSIONS
  HBV infection (either active or past) is particularly frequent in HIV-positive IDUs. Most cases have markers of past infection. Isolated detection of anti-HBc (absence of anti-HBs) is more common in HIV-positive than in HIV-negative IDUs. Despite their progressive immunosuppression, both anti-HBs loss and HBV reactivation are rare in HIV-infected IDUs.
authors.affiliation: Department of Internal Medicine, Complejo Hospitalario Universitario, Santiago de Compostela, Spain.
authors.forename: M L
authors.initials: ML
authors.lastname: Rodríguez-Méndez
authors.forename: A
authors.initials: A
authors.lastname: González-Quintela
authors.forename: A
authors.initials: A
authors.lastname: Aguilera
authors.forename: E
authors.initials: E
authors.lastname: Barrio
mesh_terms: D000293:Adolescent; D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D015658:HIV Infections / Q000150:complications*; D015497:HIV-1; D006509:Hepatitis B / Q000150:complications* / Q000175:diagnosis; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D015819:Substance Abuse, Intravenous / Q000150:complications*