Contacts of retreatment tuberculosis cases with a prior poor treatment outcome are at increased risk of latent tuberculosis infection

Abstract

<div class="section"> <a class="named-anchor" id="S1"> <!-- named anchor --> </a> <h5 class="section-title" id="d9149793e162">Objectives</h5> <p id="P1">To estimate the prevalence of and risk factors for latent tuberculosis infection (LTBI) among contacts of index patients with tuberculosis (TB) with a prior history of active TB disease and TB treatment (retreatment cases). </p> </div><div class="section"> <a class="named-anchor" id="S2"> <!-- named anchor --> </a> <h5 class="section-title" id="d9149793e167">Methods</h5> <p id="P2">A cross-sectional population-based study was conducted using data from the national TB contact surveillance program in the country of Georgia. Contacts of retreatment cases were investigated and tuberculin skin testing was offered. Bivariate and multivariable analyses were performed to calculate odds ratios and 95% confidence intervals for risk of LTBI among contacts. </p> </div><div class="section"> <a class="named-anchor" id="S3"> <!-- named anchor --> </a> <h5 class="section-title" id="d9149793e172">Results</h5> <p id="P3">The prevalence of LTBI was significantly higher among contacts whose index TB patient had a prior unfavorable treatment outcome compared to those with a favorable outcome (OR=3.14). Contacts whose index TB case previously failed therapy (OR=6.43), was lost to follow-up (OR=5.63) or completed treatment (OR=3.33) had a significantly higher prevalence of LTBI compared to contacts of previously cured TB cases. </p> </div><div class="section"> <a class="named-anchor" id="S4"> <!-- named anchor --> </a> <h5 class="section-title" id="d9149793e177">Conclusions</h5> <p id="P4">Among contacts of active TB retreatment cases, the risk of LTBI was related to the outcome of the index case’s previous TB treatment. Efforts aimed at reducing treatment loss to follow-up should be emphasized to enhance TB control efforts and may also decrease LTBI and active TB among contacts. </p> </div>