Background Tuberculosis (TB)-immunoreactivity, measured in vivo (tuberculin skin test (TST)) or in vitro (interferon gamma release assay (IGRA)), can be found in latent, active or even following clearance of TB infection. In this case-control study, we compared the systemic and ocular outcomes between patients with or without TB-immunoreactivity, who received immunomodulatory therapy (IMT) for non-infectious uveitis.

Methods We retrospectively reviewed charts of patients with (cases) or without (controls) TB-immunoreactivity (TST±IGRA), who received conventional IMT for ≥6 months, for the treatment of non-infectious uveitis. Patients who received prior or concomitant anti-TB therapy were excluded. Systemic and ocular outcomes were compared between both groups.

Results 36 cases and 70 controls (gender-matched and age-matched) were included. New-onset pulmonary or extrapulmonary TB developed in one case and none of the controls. Based on this outcome, the absolute risk increase for systemic TB reactivation was noted to be 0.028 (95% CI 0.005 to 0.051) and the number needed to harm was 36. The incidence of persistent or recurrent (worsening ≥2 grades) intraocular inflammation during IMT was comparable between both groups (cases 18/36, controls 35/70, p=1.0). A change in anatomical site of presentation at recurrence was not seen in any case, but in six controls (p=0.15). No new focal chorio-retinal lesions were noted in either group.

Conclusions Conventional IMT has a very low risk of systemic TB reactivation, and no additional detrimental effect on ocular outcomes, in TB-immunoreactive patients with non-infectious uveitis.