Patients With Negative Sputum Smear Have Higher Mortality Risk

Delayed diagnosis of pulmonary tuberculosis is common in HIV patients, researchers in Italy warn. "HIV-infected patients with pulmonary tuberculosis exhibit atypical radiological presentation and negative sputum smear more frequently than their HIV-negative counterparts," explained Dr. Fabrizio Palmieri and colleagues at the Lazzaro Spallanzani National Institute for Infectious Diseases in Rome. Their report, "Pulmonary Tuberculosis in HIV-Infected Patients Presenting with Normal Chest Radiograph and Negative Sputum Smear," was published in Infection (2002;30(2):68-74).

The confounding characteristics of TB in HIV patients significantly increase their mortality risk due to delayed treatment, Palmieri and coauthors said. The researchers reviewed data from 146 HIV patients with confirmed pulmonary TB. They compared the outcome of TB infection in patients with positive sputum smears, negative sputum smears with chest x-rays consistent with tuberculosis, and negative sputum smear and chest x-rays with a normal appearance, according to the report. Patients with negative sputum smears and normal chest x-rays had a lower survival rate than either those with positive sputum smears or positive chest X-rays.

"Decreased survival was observed in HIV-infected patients with pulmonary tuberculosis and with both negative sputum smear and normal chest x-ray presentation," Palmieri and colleagues concluded. "This may primarily be a result of delayed tuberculosis diagnosis and initiation of antituberculous therapy." When TB treatment was started within eight weeks of test sample collection, the discrepancies in life expectancy between the three groups were no longer significant.

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