TUBERCULIN SKIN-TEST REACTIVITY, ANERGY, AND HIV-INFECTION IN HOSPITALIZED-PATIENTS

PURPOSE: Detection of latent tuberculosis infection is an important st ep in the control of tuberculosis because high-risk persons may be giv en preventive therapy. The value of tuberculin skin testing in individ uals with human immunodeficiency virus (HIV) infection, however, is li mited by anergy. We evaluated the prevalence of tuberculin skin test r eactivity, anergy, and HIV infection in a group of hospitalized patien ts in an area where both tuberculosis and HIV infection are prevalent. PATIENTS AND METHODS: Three hundred fifty-one patients consecutively admitted to a medical service of a large urban teaching hospital were enrolled in the study. All those with no documented history of a posit ive tuberculin skin test were evaluated on admission with purified pro tein derivative (PPD) by the Mantoux test, and with anergy testing usi ng a multiple-puncture device. HIV testing was offered to all patients who did not have a known history of HIV infection, and was performed when informed consent was obtained. RESULTS: Forty-one patients (12%) had a documented history of a positive PPD. Of the remaining 310 patie nts, 62 (20%) had a PPD response of greater than or equal to 10 mm ind uration. Fifty-two (15%) of the 351 patients were HIV positive. None o f the HIV-infected patients was PPD positive. Anergy was found in 63% of the HIV-infected patients and 28% of the HN-seronegative patients. Independent risk factors for a positive PPD included age >55, male sex , and hypertension. HN infection, current steroid use, and a history o f cancer were associated with a negative PPD. Independent risk factors for anergy included HIV infection, current corticosteroid use, renal failure, pneumonia, and a history of cancer. Of the 62 new PPD-positiv e patients, 30 (48%) were candidates for chemoprophylaxis. Additionall y, 30 (63%) of 48 HIV-seropositive patients who were completed testing were anergic and might be candidates for chemoprophylaxis. Almost all of the patients eligible for chemoprophylactic therapy would have bee n detected if only patients at increased risk for developing tuberculo sis were screened. CONCLUSIONS: Tuberculosis infection, HIV infection, and anergy were common in patients admitted to this medical service. Interpretation of PPD reactivity was confounded by a high prevalence o f anergy, particularly in HIV-infected patients. A large proportion of patients tested were candidates for chemoprophylaxis. Routine tubercu lin skin testing with anergy testing for high-risk patients on admissi on to the hospital is useful for identifying patients who might benefi t from prophylaxis to help control the spread of tuberculosis.