Latent tuberculosis infection and COVID-19: analysis of a cohort of patients from Careggi University Hospital (Florence, Italy)

Background: In the available literature, data regarding the relationship between the Coronavirus-19 disease (COVID-19) and active or latent tuberculosis (TB) are few and discordant. Methods. We conducted a retrospective study to examine the impact of latent tuberculosis infection (LTBI) on COVID-19 clinical progression and in-hospital mortality in a pre-vaccinal era and in a low-TB prevalence area. We selected 213 patients out of 495 admitted with COVID-19 in a tertiary-level Italian hospital from February to December 2020, who underwent QuantiFERON-TB test (QFT) and/or chest radiological exam. Results. Based on QFT result and radiological findings, the population was divided into three groups: (i) QFT negative and without radiological TB sequelae (Neg, 76.1%); (ii) QFT positive and without radiological TB sequelae (Pos, 7.0%); (iii) radiological TB sequelae regardless of QFT result (Seq, 16.9%). In-hospital mortality and orotracheal intubation (OTI) resulted significantly higher in Seq group than in the other two cohorts (respectively, Seq 50% vs Pos 13.3% vs Neg 9.3%, p  < 0.001; Seq 16.7% vs Pos 6.7% vs Neg 4.9%, p  = 0.04). Considering Pos and Seq cohorts as populations with defined LTBI, in-hospital mortality (39.2%, p  < 0.001) and OTI risk (13.7%, p  = 0.02) were statistically higher in respect to patients without LTBI. By multivariate analysis, we evidenced that Charlson Comorbidity Index and belonging to Seq group were significantly associated with the three groups in-hospital mortality. Conclusion. Latent tuberculosis infection appears significantly more common in patients presenting with severe COVID-19 than non-severe disease, with a significantly higher risk of in-hospital mortality and OTI.