Changes in characteristics of inmates with latent tuberculosis infection

Objectives: Health and social characteristics place prisoners at high risk for progression from latent tuberculosis infection (LTBI) to tuberculosis (TB), but completion of LTBI therapy is low with many patients lost to follow-up after release. Despite decreases in active TB, demographic characteristics of active cases have remained relatively unchanged. This study investigated whether characteristics have changed in inmates diagnosed with LTBI in San Francisco, CA, USA.

Study design: Cross-sectional.

Methods: Data from baseline interviews of randomized trials conducted in 1998-1999 and 2004-2007 were compared.

Results: In both time periods, most subjects with LTBI (>60%) were Latinos, while the proportion in both the jail and San Francisco remained at 15-20%. Overall, the prisoners interviewed in 2004-2007 were less likely to have been on medication for LTBI previously, and expressed more likelihood of finishing their medication compared with those interviewed in 1998-1999. In 2004-2007, the foreign-born subjects were more likely to prefer English to Spanish, to have been in stable housing and to have been employed before jail compared with 1998-1999, while no such changes were seen between the two time periods for US-born subjects.

Conclusions: The pool of TB-infected individuals coming from a jail is not static, and understanding the changes over time is of importance for targeted programmes. Given the high infection rate and the predominance of foreign-born individuals who may have received bacillus Calmette-Guérin vaccination, screening with interferon-gamma release assay may be beneficial to identify those with true infection.