Background Mycobacterium tuberculosis (TB) is a common opportunistic infectious disease and an important cause of morbidity and mortality among patients with systemic lupus erythematosus (SLE), especially in Asia. China has the second highest TB burden in the world, with an estimated prevalence of 108 TB cases per 100,000 individuals in 2010. Although TB is endemic in China, studies investigating the prevalence and clinical spectrum of TB in patients with SLE are scarce.
Objectives This study aimed to describe the characteristics and risk factors for infection with TB SLE patients from Southern China and investigate whether serum procalcitonin (PCT) level in SLE patients is a predictor of disseminated TB.
Methods This study involved a retrospective review of the medical records of 782 patients admitted to the First Affiliated Hospital of Sun Yat-Sen University between January 2009 and December 2012. Demographic and clinical characteristics, and laboratory, imaging, and therapeutic data were collected and assessed.
Results 42 SLE patients experienced 56 episodes of confirmed active TB (cases: 32 females; 10 males). Accordingly, TB had a prevalence of 5.4% (42/782) in the study cohort. 31 (55.4%) of the 56 episodes were pulmonary TB, and 25 (44.6%) were extra-pulmonary TB. Among the 25 episodes of extra-pulmonary TB, TB meningitis (16.1%) was the most common, followed by TB pleuritis, TB lymphadenitis, articular TB, spinal TB, and TB peritonitis. Logistic regression multivariate analysis indicated that anemia [odds ratio (OR) =2.7, 95% confidence interval (CI) =1.2–6.2, P=0.02] and the dose of glucocorticoid (GC) (OR=1.03, 95% CI=1.01–1.06, P=0.02) were positively associated with the incidence of TB. 24 SLE patients experienced 27 episodes of disseminated TB (pulmonary miliary TB, n=13; pulmonary TB with concomitant TB meningitis, n=7; pulmonary TB with concomitant retroperitoneal lymphadenopathy due to TB, n=2; pulmonary TB with concomitant articular TB, n=2). Mortality was higher in cases with disseminated TB. Patients with disseminated TB had a significantly higher ESR and mean serum PCT level compared to patients with non-disseminated TB. In multivariate regression analysis, serum PCT level above the normal range was a predictor of disseminated TB (OR=56.0, 95% CI=1.7–1828.0, P=0.02).
Conclusions SLE patients in Southern China are at high risk for TB, especially extra-pulmonary and disseminated TB. Anemia and the dose of GC were associated with the incidence of TB. Serum PCT level above the normal range represents a useful biomarker for the prediction of disseminated TB in SLE patients.
Disclosure of Interest None declared