Abstract: SA-PO189
Rate and Predictors of Developing Monoclonal Gammopathy of Renal Significance (MGRS) Lesion on Renal Biopsy in Patients with Positive Monoclonal Studies
Session Information
- Onco-Nephrology: Clinical
November 09, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Onco-Nephrology
- 1500 Onco-Nephrology
Authors
- Klomjit, Nattawat, Mayo Clinic, Rochester, Minnesota, United States
- Leung, Nelson, Mayo Clinic, Rochester, Minnesota, United States
- Fervenza, Fernando C., Mayo Clinic, Rochester, Minnesota, United States
- Sethi, Sanjeev, Mayo Clinic, Rochester, Minnesota, United States
- Zand, Ladan, Mayo Clinic, Rochester, Minnesota, United States
Background
Monoclonal gammopathy (MG) can cause renal damage in a subset of patients known as MGRS. However, the rate of finding an MGRS lesion on a biopsy in a patient with MG and the clinical factors that would predict the likelihood of finding such lesions remains unknown
Methods
We identified all patients that had a positive serum MG based on a positive serum electrophoresis or immunofixation between 2013 through 2018 at the Mayo Clinic Rochester. We then excluded those patients who had a diagnosis of multiple myeloma, amyloidosis, or those with a renal transplant.
Results
We identified 4257 patients who met the inclusion criteria, of which 105 had a renal biopsy (2.47%). Of the 105 patients, 25 (23.8%) had an MGRS lesions. The most common MGRS lesions included proliferative glomerulonephritis with monoclonal immunoglobulin deposition (PGNMID) (n=10, 40%) followed by cryoglobulinemic vasculitis (n=5, 20%). In the remaining 80 patients, the most common lesions included arteriosclerosis (n=19, 23.75%), diabetic nephropathy (n=14, 17.5%), ANCA associated vasculitis (n=8, 8.8%) and IgAN (n=8, 8.8%). At the time of renal biopsy, there were no differences in age, sex, serum creatinine, hemoglobin and type of light chain between 2 groups. Compared to non-MGRS patients, MGRS patients had a significantly higher systolic blood pressure (p= 0.03) and more likely to have IgG heavy chain (p =0.05). Hematuria at time of the renal biopsy was the most significant predictor of finding an MGRS lesion with an OR of 6.21 (2.1-18.3, p=0.0003), followed by proteinuria >3.5 g/d with OR of 2.61 (1.01-6.7, p=0.04), and an elevated ratio of affected/unaffected light chain (OR= 1.08, 1.0-1.16, p=0.0001). Having a combination of hematuria and proteinuria≥2 g/day was also highly predictive with an OR of 5.67 (2.0-16.1, P=0.001).
Conclusion
Among patient with a positive MG who had a renal biopsy in the absence of amyloidosis, 75% had a lesion unrelated to the MG with arteriosclerosis and DN being the most common findings. Hematuria, nephrotic range proteinuria or high risk features (hematuria+proteinuria≥2 g) were the strongest predictors of finding an MGRS lesion.