Chronic lung disease and HIV infection are risk factors for recurrent tuberculosis in a low-incidence setting.

SETTING

Programmatic data from the United States on tuberculosis (TB) recurrence are limited.

OBJECTIVES

To determine the TB recurrence rate and to determine if chronic lung disease (CLD) and human immunodeficiency virus (HIV) infection are risk factors for recurrence in this population.

DESIGN

Nested case-control study among TB cases reported to the Tennessee Department of Health between 1 January 2000 and 31 December 2006. Time at risk for recurrence was through 31 December 2007. Multiple imputation accounted for missing data.

RESULTS

Of 1431 TB cases, 20 cases recurred (1.4%, 95%CI 0.9-2.1). Median time at risk for recurrence was 4.5 years (interquartile range 2.7-6.1). Initial and recurrent Mycobacterium tuberculosis isolates were available for genotyping for 15 patients; 12 were consistent with relapse (0.8%, 95%CI 0.4-1.5) and three with re-infection (0.2%, 95%CI 0.04-0.6). HIV infection (OR 5.01, P = 0.04) and CLD (OR 5.28, P = 0.03) were independently associated with recurrent TB, after adjusting for a disease risk score. HIV infection was a risk factor for TB re-infection (P < 0.001).

CONCLUSIONS

In this low-incidence US population, the TB recurrence rate was low, but CLD and HIV were independent risk factors for recurrence. HIV infection was also a risk factor for TB re-infection.