Effect of Monoclonal Gammopathy on Risk of Kidney Failure among Patients with Chronic Kidney Disease

Background: Monoclonal gammopathy of undetermined significance (MGUS) and chronic kidney disease (CKD) are common conditions. MG of renal significance (MGRS) represents a subgroup of MGUS in which monoclonal protein exerts deleterious effect on the kidney, and treating the underlying clone may help prevent progression to end stage renal disease (ESRD). However, the exact prevalence of MGRS remains largely unknown, and the significance of a positive monoclonal protein test in individuals with CKD is not well understood. Methods: We conducted a single-center retrospective analysis for patients with CKD between 2000 and 2019 and included 15,337 patients without MGUS and 626 patients with MGUS. The primary outcome was the rate of progression to ESRD, calculated using Time to ESRD (TTESRD). Results: After a median follow-up of 19.7 months, there was no statistically significant difference in the rate of ESRD between CKD patients with MGUS and those without MGUS (4.8% vs. 6%, p = 0.2). Considering the duration of follow-up and death as competing risks, there was no significant difference in TTESRD between both groups (HR 1.6, 95% CI: 0.99-2.59, p = 0.057). Even after adjusting for age, gender, race, CKD stage, diabetes, and hypertension, no significant difference in TTESRD was found between the two groups (HR 1.64, 95% CI: 0.99-2.72, p = 0.056). Conclusion: For most CKD patients, the identification of monoclonal protein did not provide additional information on the risk of ESRD. O