# Risk Factors of Progression to Active Tuberculosis in Rheumatic Patients With Latent Tuberculosis: A Retrospective Study

## TL;DR

This study identifies high-dose glucocorticoid therapy as a risk factor for active tuberculosis in rheumatic patients with latent tuberculosis.

## Contribution

The study reveals that glucocorticoid doses of 20 mg/day or more significantly increase the risk of latent tuberculosis progressing to active disease in rheumatic patients.

## Key findings

- Glucocorticoid therapy at 20 mg/day or more is an independent risk factor for latent tuberculosis activation (odds ratio = 3.59).
- Systemic lupus erythematosus and rheumatoid arthritis account for half of the rheumatic patients with latent tuberculosis.
- Only 18.60% of rheumatic patients were screened for latent tuberculosis infection.

## Abstract

In rheumatism patients, the immune system erroneously attacks the body′s own tissues. This impairs the body′s defense against external pathogens and is a contributing factor to the occurrence of tuberculosis infection. The primary objective of this investigation was to examine the risk factors for the progression from latent tuberculosis infection (LTBI) to active tuberculosis (ATB) in patients with rheumatic diseases (RD).

RD cover a wide range of disorders affecting the skeletal system, joints, and adjacent soft tissues. When the human body is infected by Mycobacterium tuberculosis, the condition is classified as either LTBI or ATB, depending on the presence or absence of typical clinical symptoms. A retrospective study was conducted at the Xijing Hospital of the Fourth Military Medical University. Specifically, the Laboratory Information System was used to investigate patients diagnosed with RD from January 2012 to October 2022.

The study included a total of 32,235 individuals diagnosed with rheumatism, of whom only 18.60% were screened for LTBI. The overall incidence of LTBI was 25.33%. Among the 629 RD inpatients with LTBI, systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) accounted for half, and 56.44% received glucocorticoid (GC) therapy. Risk‐factor assessment for ATB was conducted in 247 cases. A GC dose of 20 mg/day or more was an independent risk factor for LTBI activation (odds ratio = 3.59, 95% CI: 1.26–10.29, p = 0.017).

In China, RD patients have a relatively high risk of LTBI. In clinical practice, LTBI screening should be routinely performed for RD patients before initiating GC therapy at a dose of ≥ 20 mg/day. For patients with SLE and RA undergoing continuous GC treatment, close monitoring is essential. In addition, clinicians should enhance the diagnostic pathways and treatment management for these patients to prevent the occurrence of ATB.