Tuberculosis remains a leading contributor to morbidity due to serious infections in Indian patients of SLE

Abstract

Introduction: Infections are a major cause of morbidity and mortality in systemic lupus erythematosus (SLE). We assessed the incidence and risk factors for major infections in SLE in India.

Methods: A retrospective review of a cohort of 1354 patients of adult SLE (ACR 1997 criteria) seen between 2000 and 2021 at a single center was conducted. Serious infections (need for hospitalisation, prolonged intravenous antibiotics, disability, or death) were recorded. Cox regression was used to determine factors associated with serious infection and the effects of serious infection on survival and damage.

Results: Among the 1354 patients (1258 females, mean age of 30.3 years, follow-up of 7127.89 person-years), there were 439 serious infections in 339 patients (61.6 per 1000 person-years follow-up). Bacterial infections (N = 226) were the most common infection followed by mycobacterial infections (n = 81), viral (n = 35), and then invasive fungal infections (N = 13). Mycobacterium tuberculosis was the single most common microbiologically confirmed organism with incidence of 1136.4/100,000 person-years with 72.8% of them being extrapulmonary. Infection free survival at 1 year and 5 years was 82.9% and 73.8%. There were 119 deaths with infection attributable mortality in 65 (54.6%). On multivariable Cox regression analysis, higher baseline activity (HR 1.02, 1.01-1.05), gastrointestinal involvement (HR 2.75, 1.65-4.69), current steroid dose (HR 1.65, 1.55-1.76), and average cumulative steroid dose per year (HR 1.007, 1.005-1.009) were associated with serious infection and higher albumin (HR 0.65, 0.56-0.76) was protective. Serious infections led to greater damage accrual (median SLICC damage index of 1 vs. 0) and mortality (HR was 18.2, 32.7 and 81.6 for the first, second, and third infections).

Conclusion: Serious infections remain a major cause of mortality and damage accrual in SLE and higher disease activity, gastrointestinal involvement, hypoalbuminemia, current steroid dose, and cumulative steroid dose are the risk factors for it.

Keywords: Infection; Staphylococcus aureus; Streptococcus pneumoniae; Systemic lupus erythematosus; Tuberculosis.