# Assessment of Thrombotic Risk in Patients with Tuberculosis and SARS-CoV-2 Coinfection: A Retrospective Study

## TL;DR

This study found that patients with both tuberculosis and COVID-19 may have a higher risk of blood clots during hospitalization compared to those with tuberculosis alone.

## Contribution

The study explores the combined thrombotic risk of tuberculosis and SARS-CoV-2 coinfection, a previously understudied area.

## Key findings

- Thrombotic events were more frequent in the tuberculosis and COVID-19 co-infection group (22.5% vs. 10%).
- Patients with coinfection had significantly higher proportions of elevated Padua scores (55% vs. 20%).
- Tuberculosis and COVID-19 coinfection remained associated with higher odds of thrombotic events in age-adjusted analysis.

## Abstract

Background/Objectives: Tuberculosis and COVID-19 are two major infectious diseases with significant inflammatory and immunological impact on infected hosts and both conditions are independently associated with a prothrombotic state. However, evidence regarding their combined effect on in-hospital thrombotic risk remains limited. In this study, we aimed to explore whether patients with tuberculosis and COVID-19 coinfection are at a higher risk of developing thrombotic events during hospitalization than patients diagnosed with tuberculosis alone. Materials and Methods: We performed a retrospective, single-center cohort study, including adults hospitalized at the Pulmonology Clinic, Adult Tuberculosis ward of Mures County Clinical Hospital, between 2021 and 2023. Two groups were analyzed: patients with pulmonary tuberculosis who developed COVID-19 during hospitalization (n = 40) and patients with pulmonary tuberculosis without documented SARS-CoV-2 infection (n = 40). Demographic, clinical, laboratory, and imaging data were extracted from medical records. Padua and IMPROVE-DD scores were calculated retrospectively, a rapid mini-score was evaluated exploratorily. Comparisons between groups were performed using appropriate statistical tests and unadjusted odds ratios (ORs) with 95% confidence intervals (CIs) were reported. Given the limited number of events, an age-adjusted Firth penalized logistic regression model was used for multivariable analysis. Results: Thrombotic events occurred more frequently in the tuberculosis and COVID-19 co-infection group (22.5% vs. 10%), although statistical significance was not reached (p = 0.22; OR = 2.61). Patients with coinfection had significantly higher proportions of elevated Padua scores (55% vs. 20%, p = 0.002; OR = 4.88), while IMPROVE-DD showed values near the conventional threshold for statistical significance (37.5% vs. 17.5%, p = 0.07). D-dimer values did not reach statistical significance (p = 0.07) and platelet counts were significantly higher in patients with tuberculosis only (p = 0.001). Mortality did not differ significantly between groups (15% vs. 10%, p = 0.73). In age-adjusted multivariable analysis, tuberculosis and COVID-19 coinfection remained associated with higher odds of thrombotic events, with wide confidence intervals. Conclusions: Patients with concomitant tuberculosis and COVID-19 showed a higher thrombotic risk profile (Padua score) and numerically higher rates of in-hospital thrombotic events, without reaching statistical significance. Findings should be interpreted as exploratory and hypothesis-generating. Larger prospective studies with systematic imaging and multivariable adjustment are needed.