Incidence and Risk Factors Associated with Latent Tuberculosis Infection and Pulmonary Tuberculosis among People Deprived of Liberty in Colombian Prisons

Abstract

People deprived of liberty (PDL) are at high risk of acquiring Mycobacterium tuberculosis infection (latent tuberculosis infection [LTBI]) and progressing to active tuberculosis (TB). We sought to determine the incidence rates and factors associated with LTBI and active TB in Colombian prisons. Using information of four cohort studies, we included 240 PDL with two-step tuberculin skin test (TST) negative and followed them to evaluate TST conversion, as well as, 2,134 PDL that were investigated to rule out active TB (1,305 among people with lower respiratory symptoms of any duration, and 829 among people without respiratory symptoms and screened for LTBI). Latent tuberculosis infection incidence rate was 2,402.88 cases per 100,000 person-months (95% CI 1,364.62-4,231.10) in PDL with short incarceration at baseline, and 419.66 cases per 100,000 person-months (95% CI 225.80-779.95) in individuals with long incarceration at baseline (who were enrolled for the follow after at least 1 year of incarceration). The TB incidence rate among PDL with lower respiratory symptoms was 146.53 cases/100,000 person-months, and among PDL without respiratory symptoms screened for LTBI the incidence rate was 19.49 cases/100,000 person-months. History of Bacillus Calmette-Guerin vaccination decreased the risk of acquiring LTBI among PDL who were recently incarcerated. Female sex, smoked drugs, and current cigarette smoking were associated with an increased risk of developing active TB. This study shows that PDL have high risk for LTBI and active TB. It is important to perform LTBI testing at admission to prison, as well as regular follow-up to control TB in prisons.

Figure 1.

Flow chart of persons screened for LTBI and included in the cohort between 2016 and 2018. TST: Tuberculin skin test. LTBI: Latent tuberculosis infection.

Figure 2.

Tuberculosis (TB) cases during incarceration (time in years). Time zero is the time of prison entry. Twelve TB cases were diagnosed within 3 months of incarceration (prevalent cases).