Abstract: FR-PO749

Diagnosis of Renal Vasculitis Flare Using usCD163: A Multi-Centre Prospective Study

Session Information

Category: Glomerular

  • 1004 Clinical/Diagnostic Renal Pathology and Lab Medicine

Authors

  • Moran, Sarah Margaret, Trinity Health Kidney Centre, Dublin, Ireland
  • Conlon, Niall P, Trinity College Dublin, Dublin, Ireland
  • Little, Mark Alan, Trinity Health Kidney Centre, Dublin, Ireland

Group or Team Name

  • Vasculitis Ireland Network
Background

Urinary sCD163 displays excellent potential for active renal vasculitis detection at AAV diagnosis. The clinical utility of usCD163 is in the diagnosis of renal vasculitis flare, potentially obviating the need for biopsy and detecting active renal vasculitis prior to further injury.

Methods

AAV patients were prospectively recruited with potential renal vasculitis flares from a multicentre cohort. Physicians judged the flare probability as High or Possible. An independent committee adjudicated on renal flare diagnosis (BVAS major criteria:RBC casts &/or 30% increase in creatinine or renal biopsy). Urine creatinine-normalised sCD163 levels were measured by ELISA.

Results

44 patients were prospectively recruited, 32% with renal flare. Creatinine was 1.7mg/dL (IQR 1.0-3.2, 78% increase from baseline) and 1.5mg/dL (IQR 1.1-1.7, 2.8% increase) in flare and non-flare (p=0.02). Median usCD163 levels were significantly higher in patients with adjudicated renal flare (469.6 ng/mmol (IQR 363.8-2974)) compared to non-flare (25.4 (IQR 3.9-80.8), p<0.0001)). Median usCD163 levels were not elevated in potential renal flare mimics, including sepsis (62.1ng/mmol IQR 27.8-155.3), acute kidney injury (22.4ng/mmol IQR 0-78.7) or systemic flare (22.4ng/mmol, IQR 21-107.7).

Conclusion

usCD163 is diagnostic of renal vasculitis flare in prospectively observed patients with AAV, and is superior to initial physician assessment and BVAS major renal criteria.

Table 1: Biomarker characteristics.
 SensitivitySpecificityPLRNLRPPVNPVAUC
usCD163 >300ng/mmol91.7%96.8%28.40.0991.7%96.8%0.93
Physician High Probability47.4%88%3.950.675%68.8%0.71
BVAS WG Major Criteria57.1%82.8%3.310.5261.5%68.1%0.74

PLR= Positive Likelihood Ratio. NLR=Negative Likelihood Ratio. PPV=Positive Predictive Value. NPV=Negative Predictive Value. AUC=Area Under Curve

Funding

  • Government Support - Non-U.S.