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Abstract: PO1564

Patients with Glomerular Disease Are at Very High Risk of TB Infection Compared to the General Population

Session Information

Category: Glomerular Diseases

  • 1203 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Gunning, Heather M., BC Provincial Renal Agency, Vancouver, British Columbia, Canada
  • Canney, Mark, BC Provincial Renal Agency, Vancouver, British Columbia, Canada
  • Zheng, Yuyan, BC Provincial Renal Agency, Vancouver, British Columbia, Canada
  • Hogan, Jonathan, Division of Nephrology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
  • Barbour, Sean, BC Provincial Renal Agency, Vancouver, British Columbia, Canada
Background

Advanced kidney disease is a known risk factor for active TB disease; however this risk has not been studied in patients with glomerular disease (GN). We sought to determine the incidence of TB disease in patients with GN and to explore the risk associated with immunosuppression (IS) treatment.

Methods

A population-level cohort was created using a centralized kidney biopsy registry (2000-2012) of all GN cases in British Columbia, Canada: IgA nephropathy (IgAN) n=857, focal segmental glomerulosclerosis (FSGS) n=564, ANCA-GN n=404, lupus nephritis (LN) n=360, membranous nephropathy (MN) n=398, minimal change disease (MCD) n=191, and other GN (n=305). TB disease was ascertained by linkage to administrative databases. High TB incidence was defined as >30/100,000 person years (PY) consistent with the definition used in first-world countries. Incidence rates were standardized to the general population to generate standardized incidence ratios (SIR, 95% CI). Hazard ratios were calculated using Cox proportional hazards regression.

Results

During a median follow-up 6.2 years, there were 41 cases of TB disease. TB incident rate was 197.4/100,000PY, and was higher in patients with LN vs. other types of GN (403.0/100,000PY, p<0.05). TB incidence in patients with GN was 23-fold higher than the general population (SIR 23.4, 16.8-31.7), and was high in both Canadian and foreign-born patients (range 124.1-579.6/100,000PY). TB incidence was higher during periods of IS use (282.4 vs. 147.9 per 100,000PY, p<0.05), and most cases (80.5%) had IS exposure prior to TB diagnosis. Time from IS to TB disease was highly variable, with median 3.9 years but 24% of TB cases occurred within 1 year. Reduced kidney function and higher proteinuria were also associated with increased TB risk (Table).

Conclusion

Patients with GN have a high risk of TB disease, irrespective of GN type or country of origin. TB disease can occur within months of starting IS, suggesting that all GN patients should be screened for latent TB early in their disease course.

Risk Factors for TB in GN