Objective: To identify factors associated with active tuberculosis (TB) in patients with systemic lupus erythematosus (SLE).
Methods: We performed a retrospective case-control study in two tertiary care teaching hospitals in Medellín, Colombia. From January 2007 to December 2017, a total of 268 patients with SLE were included. SLE patients with TB (cases) were matched 1:3 with SLE patients without TB (controls) by disease duration and the date of the hospitalization in which the diagnosis of TB was made (index date of cases) to the nearest available rheumatology hospitalization in the matched controls (± 2 years). Conditional univariable and multivariable logistic regression analyses were performed.
Results: Sixty-seven cases and 201 controls were assessed. Only pulmonary TB occurred in 46.3%, only extrapulmonary TB in 16.4% and disseminated TB in 37.3% of cases. Multivariable logistic regression analysis showed that lymphopenia (OR, 2.91; 95% CI 1.41-6.03; P = 0.004), 12-month cumulative glucocorticoid dose ≥ 1830 mg (OR, 2.74; 95% CI 1.26-5.98; P = 0.011), and having been treated with ≥ 2 immunosuppressants during the last 12 months (OR, 2.81; 95% CI 1.16-6.82; P = 0.022) were associated with TB after adjusting for age, sex, ethnicity, disease duration, disease activity, and comorbidity index. A trend towards an association of kidney transplantation with TB was also found (OR, 3.77; 95% CI 0.99-14.30; P = 0.051).
Conclusion: Among SLE patients, cumulative glucocorticoid dose, lymphopenia, and the use of ≥ 2 immunosuppressants during the last 12 months were associated with active TB infection. Key Points • Among SLE patients, a cumulative dose of glucocorticoids equivalent to 5 mg/day of prednisone during the last 12 months is independently associated with the development of TB. • The use of two or more immunosuppressants during the last 12 months is also a risk factor for TB infection development is SLE patients. • Lymphopenia is predominant in SLE patients with TB, being especially profound in those with disseminated TB. • Renal transplant recipients with SLE also have an elevated risk of TB.
Keywords: Glucocorticoids; Immunosuppressants; Opportunistic infections; Systemic lupus erythematosus; Tuberculosis.