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Kidney Week

Abstract: PO2184

Nephrology and Hematology Referral Trends in CKD Patients with Monoclonal Gammopathy and Factors Associated with Deferring Kidney Biopsy

Session Information

  • Onco-Nephrology - 1
    October 22, 2020 | Location: On-Demand
    Abstract Time: 10:00 AM - 12:00 PM

Category: Onco-Nephrology

  • 1500 Onco-Nephrology

Authors

  • Klomjit, Nattawat, Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, Minnesota, United States
  • Zand, Ladan, Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, Minnesota, United States
Background

Many patients with CKD are managed by their primary care providers (PCP). The presence of monoclonal gammopathy (MG) in the setting of CKD raises the possibility of monoclonal gammopathy of renal significance (MGRS) which would require a nephrology or hematology referral. However, rate and factors that affect specialist referral in this population remains unknown. Moreover, factors for deferring a kidney biopsy are also unknown.

Methods

We retrospectively identified adult CKD patients with MG at our center from 2017-2018. Baseline characteristics and laboratories studies were compared between nephrology/hematology referral group (RG) vs. no referral group (NRG). We also assessed the rate of kidney biopsy and the reasons for not pursuing a biopsy in the referral group.

Results

We identified 596 CKD patients with MG. Of these, 416 (69.8%) were seen by nephrologis/hematologist & 180 (30.2%) were not referred to either. Of the 180, 32% were followed by their PCP (n=57), 30% by cardiologist (n=54), and 19% by neurologist (n=35). Demographics were similar between the two groups. Patients in the NRG were more likely to have coronary artery disease, dementia, active or metastatic cancer. In multivariate analysis, 24-hr urinary protein (OR: 1.36 (1.01, 2.09)), abnormal FLC (OR 2.46 (1.29, 4.93)), and serum creatinine (OR 2.38 (1.37, 4.59)) were strong independent predictors for referral. Of 416 patients in RG, 62 (15%) patients underwent a kidney biopsy and 26 had an MGRS lesion. There were no differences in the comorbidities between the patients that were biopsied vs. those that were not. The main reason for deferring biopsy was lack of awareness of CKD or MG (142, 40%) and low suspicion for MGRS (130, 37%). In 62 patients, biopsy was not pursued as it was unlikely to change management (majority had amyloidosis). Other reasons included watchful waiting and patients’ frailty.

Conclusion

Up to 30% of CKD patients with MG are not referred to a specialist. Co-morbidities lower the rate of referral whereas impaired kidney function and higher M-spike & FLC increase referral. However, once patients are referred, the comorbidities had no impact on who underwent biopsy. Most common reason for not pursuing a biopsy was lack of awareness that patient had CKD or MG.