Enteric infections and diarrhea in human immunodeficiency virus-infected persons - Prospective community-based cohort study

Background: Persons infected with human immunodeficiency virus (HIV) are at increased risk for diarrhea and enteric infections. We studied (1) the epi demiology of enteric pathogens associated with diarrhea, (2) the diagnostic yield of stool examination and endoscopic evaluation, (3) risks to develop diarrhea, and (4) the impact of diarrhea on patients' survival. Methods: A total of 1933 participants in the Swiss HIV Cohort Study were pr ospectively followed up for a median of 25.5 months. A total of 560 diarrhe al episodes were evaluated by standardized stool examination. Endoscopic ev aluation was performed in 25% of patients with chronic diarrhea. Results: The incidence of diarrhea was 14.2 per 100 person-years (95% confi dence interval, 13.0-15.4). Among patients with CD4 cell counts below 0.05 X 10(9)/L, the probability to develop diarrhea within 1, 2, and 3 years was 48.5%, 74.3%, and 95.6%, respectively. The risk to develop diarrhea was in creased among patients with severe immunodeficiency, homosexual men, and pa tients taking antiretroviral therapy. Pneumocystis carinii chemoprophylaxis did not reduce the risk of diarrhea. Diarrhea was an independent negative predictor of survival. Enteric pathogens were detected in 16.5% of 212 acut e diarrheal episodes and in 46% of 348 chronic diarrheal episodes. The sens itivity of histological and stool examination was similar except for the di agnosis of intestinal cytomegalovirus infection and leishmaniasis, which re quired invasive evaluation. Conclusions: Intestinal infections were diagnosed in less than 50% of chron ic diarrheal episodes. The prevalence of enteric pathogens tended to decrea se during the observation period, possibly because of improved antiretrovir al therapy. Endoscopic evaluation did not improve the diagnostic yield comp ared with stool examination except for the diagnosis of cytomegalovirus ent eritis and leishmaniasis.