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July 12, 1995

Risk Factors for Tuberculosis in HIV-lnfected Persons: A Prospective Cohort Study

Author Affiliations

S. Maria Scala, Siena; Policlinico, Bari; L. Spallanzani I Divisione, Rome; SS. Annunziata, Sassari; Gemelli, Rome; Pizzardi, Bologna; Civile, Busto Arsizio; L. Spallanzani, Rome; S. Orsola, Bologna; II Policlinico, Naples; Civile Maggiore, Verona; Niguarda, Milan; S. Anna, Ferrara; Cotugno, Naples; S. Matteo, Pavia; L. Spallanzani II Divisione, Rome; S. Martino, Genoa; S. Bortolo, Vicenza; OER Lazio, Rome; Sacco Clinica, Milan; S. Anna, Como; Cisanello, Pisa; Centro Oncologico, Aviano; USL 1, Aosta; Civile, Piacenza.
From the Centro di Riferimento AIDS, Ospedale L. Spallanzani, Rome, Italy (Drs Antonucci, Girardi, and Ippolito), and Tuberculosis Programme, World Health Organization, Geneva, Switzerland (Dr Raviglione).

JAMA. 1995;274(2):143-148. doi:10.1001/jama.1995.03530020061033

Objective.  —To analyze how demographic, clinical, and laboratory characteristics influence the risk of tuberculosis in human immunodeficiency virus (HIV)— infected individuals; to examine the incidence of tuberculosis associated with change in skin test responsiveness in HIV-infected, tuberculin-negative, nonanergic individuals.

Design.  —Multicenter cohort study.

Setting.  —Twenty-three infectious disease units in public hospitals in Italy.

Subjects.  —A consecutive sample of 3397 HIV-infected subjects were considered for entry in the study. Of these, 2695 who were followed up for at least 4 weeks were enrolled in the study; 739 subjects (27.4%) were unavailable for follow-up. The median duration of follow-up was 91 weeks.

Main Outcome Measure.  —Culture-proven tuberculosis.

Results.  —Eighty-three episodes of tuberculosis were observed. Incidence rates of tuberculosis were 5.42 per 100 person-years among tuberculin-positive subjects, 3.00 per 100 person-years among anergic subjects, and 0.45 per 100 person-years among tuberculin-negative nonanergic subjects. In multivariate analysis, being tuberculin-positive (hazard ratio [HR], 9.94; 95% confidence interval [CI], 3.84 to 25.72) or anergic (HR, 3.35; 95% CI, 1.40 to 8.00), or having a CD4+ lymphocyte count less than 0.20× 109/L (HR, 4.87; 95% CI, 2.35 to 10.11) or between 0.20 and 0.35×109/L (HR, 2.35; 95% CI, 1.09 to 5.05) were statistically significantly associated with the risk of tuberculosis. Incidence of tuberculosis increased with decreasing levels of CD4+ lymphocytes in the three groups of subjects with different skin test responsiveness. Skin tests were repeated 1 year after enrollment in 604 tuberculin-negative nonanergic subjects; three cases of tuberculosis were observed among the 13 subjects who converted to tuberculin reactivity.

Conclusions.  —Risk of tuberculosis in HIV-infected persons can be more precisely quantified by jointly considering skin test reactivity and CD4+ lymphocyte count. Periodic skin tests in tuberculin-negative nonanergic individuals can be useful in identifying individuals at high risk of active tuberculosis.(JAMA. 1995;274:143-148)