Pulmonary impairment after tuberculosis.

BACKGROUND

Pulmonary impairment subsequent to a cure of pulmonary tuberculosis has been described only in selected populations.

METHODS

We compared pulmonary function in a case-control study of 107 prospectively identified patients with pulmonary tuberculosis who had completed at least 20 weeks of therapy and 210 patients with latent tuberculosis infection (LTBI).

RESULTS

Both groups had similar risk factors for pulmonary impairment. Impairment was present in 59% of tuberculosis subjects and 20% of LTBI control subjects. FVC, FEV1, FEV1/FVC ratio, and the midexpiratory phase of forced expiratory flow were significantly lower in the treated pulmonary tuberculosis patients than in the comparison group. Ten patients with a history of pulmonary tuberculosis (9.4%) had less than half of their expected vital capacity vs one patient (0.53%) in the LTBI group. Another 42 patients (39%) with tuberculosis had between 20% and 50% of the expected vital capacity vs 36 patients with LTBI (17%). After adjusting for risk, survivors of tuberculosis were 5.4 times more likely to have abnormal pulmonary function test results than were LTBI patients (p > 0.001; 95% confidence interval, 2.98 to 9.68). Birth in the United States (odds ratio [OR], 2.64; p = 0.003) and age (OR, 1.03; p = 0.005) increased the odds of impairment. Pulmonary impairment was more common in cigarette smokers; however, after adjusting for demographic and other risk factors, the difference did not reach statistical significance (p = 0.074).

CONCLUSIONS

These findings indicate that pulmonary impairment after tuberculosis is associated with disability worldwide and support more aggressive case prevention strategies and posttreatment evaluation. For many persons with tuberculosis, a microbiological cure is the beginning not the end of their illness.