Tuberculosis reactivation in referrals to public health clinics in Texas.

BACKGROUND

Screening for and treatment of latent tuberculosis infection (LTBI) have been essential components of the TB elimination strategy.

METHODS

To estimate the rate of and to identify risk factors for reactivation TB in patients in Texas with LTBI, we retrospectively analyzed 51,959 patients with LTBI identified in Texas Department of State Health Services TB clinics from 1995 to 2008.

RESULTS

We identified 200 cases of reactivation TB among the 51,959 patients in this database. The overall rate of reactivation TB was 0.038 cases per 100 person-years (95% confidence interval [CI]: 0.032-0.043). The reactivation rate in patients who did not receive a complete treatment was 0.058. The relative risk (RR) for reactivation was higher in men (RR = 1.15; 95% CI: 0.86-1.54), patients older than 50 years (RR = 1.13; 95% CI: 1.04-1.22), African American (RR = 1.21; 95% CI: 1.09-1.34), U.S.-born referrals (RR = 1.4; 95% CI: 1.11-1.76), referrals with abnormal X-rays (RR = 1.07; 95% CI: 1.03-1.12) and patients receiving treatment other than isoniazid (RR = 1.08; 95% CI: 1.03-1.13).

CONCLUSIONS

The current rate of reactivation TB in Texas is much lower than rates reported in the United States in the 1950s. Certain patients are at increased risk for reactivation and should be monitored more closely during LTBI therapy.