Background. An increasing number of patients require immunosuppressive treatment. Therefore, screening for latent tuberculosis infection (LTBI) is important to detect and potentially treat those patients who are at risk to develop active tuberculosis.

Aims. The aim of our study is to highlight the features of the patients requiring LTBI screening and the treatment regimens.

Methods. This retrospective, observational, cohort study enrolled patients referring to Villa Marelli outpatient clinic during the last 15 years. LTBI status, underlying medical conditions leading to screening, treatment regimens, duration and side effects data were collected during follow-up visits.

Results. Overall, 840 patients were screened. Mean age was 51.4 years, 58.3% were males, 84.2% Italians, 4.9% Asians, 4.3% Africans, 4.0 % South Americans and 2.6% Europeans other than Italians. Reasons for screening were dermatological autoimmune diseases 66.2%, rheumatoid arthritis 12.4%, transplant 6.3%, inflammatory bowel disorders 6.2%, hidradenitis 4.9% and 4.0% others.

A total of 363 patients underwent preventive treatment: 42.2% with isoniazid, 37.7% with isoniazid plus rifampicin, 7.4% with rifampicin and 12.7% with alternative treatment combinations. 19.6% of patients treated with isoniazid reported adverse events, followed by 19% with isoniazid plus rifampicin and 14.8% with rifampicin alone.

Conclusions. Dermatological autoimmune diseases were the most common conditions requiring LTBI screening, followed by rheumatoid arthritis. Isoniazid was the prevalent treatment but was the regimen associated with the highest incidence of adverse events.