Comparative analysis of LTBI treatment tolerance across age groups: a retrospective monocentric observational study

The detection and treatment of latent tuberculosis infection (LTBI) is a key step in eliminating tuberculosis (TB). While treatment is generally well tolerated in young patients (pts), information on its efficacy and safety in older individuals remains limited. We investigated whether pts ≥65 years old (y.o.) exhibit a higher propensity for drug intolerance resulting in treatment failure compared to younger pts. We conducted a retrospective study involving 22798 consecutive adult pts treated for LTBI at our institution from 1992 to 2023. Indications for LTBI treatment varied across age cohorts. In pts <65 y.o., primary indications were recent exposure to active TB cases (39.3%) and participation in high-risk screening programs including homeless individuals (26.9%), healthcare workers (10.6%), and migrants (8.3%). Conversely, in ≥65 y.o. pts, LTBI treatment was predominantly administered for TB prevention in immunocompromised individuals (52.7%) and those with known TB exposure (45.6%). Overall treatment completion rates were 73.6%: 73,5% in pt <65 y.o. vs 75% in pt ≥65 y.o. (p=0,2). The primary cause of treatment failure in both age groups was loss to follow-up, with higher rates in pts <65 y.o. compared to ≥65 y.o. pts (61.3% vs. 34.3%, p<0.01). Drug intolerance was a significant contributor to treatment failure in pt ≥65 y.o. (32.3% vs. 11.9% in pt <65 y.o., p<0.001), while treatment refusal showed no significant disparity between age groups (20.2% in older vs. 19.7% in younger pts, p=0.8). Despite differences, treatment success rates were similar. Our findings support the tolerability of LTBI treatment in older patients and the need for improved adherence strategies.