The prevalence of decreased glomerular filtration rate in patients with monoclonal gammopathy of undetermined significance

Abstract

Background: Renal function is more frequently decreased in patients with monoclonal gammopathy. 10 % of patients with multiple myeloma present with acute renal failure and renal function is included in CRAB criteria for the diagnosis of multiple myeloma. Aim: The aim of this study is to determine the prevalence of chronic renal failure (CRF), defined as a glomerular filtration rate (GFR) below 1.0 ml/s/1.73m2, in 101 patients with monoclonal gammopathy of undetermined significance (MGUS). Design: retrospective study Material and methods: We compared GFR estimates from serum creatinine (MDRD GFR) and serum cystatin C (CysC GFR) and looked at the correlation between free light chains (FLC) concentration and renal markers. We performed serum protein electrophoresis (SPE) with quantification of monoclonal intact immunoglobulin (MIg) and measured serum creatinine, cystatin C, Κ and Λ FLC and β2microglobulin in all patients. Results: We found CRF in 38.6% patients using estimation from serum cystatin C and 34.6 % using estimation from serum creatinine. B2microglobulin has the highest number of significant correlations; cystatin C (0.90), CysC GFR (-0.69), creatinine (0.70), MDRD GFR (-0.60), MIg concentration (0.24), Κ FLC (0.22) Λ FLC (0.34) and age (0.40). The best correlation results may be explained by the fact that β2microglobulin reflects both malignant cells burden and renal function. Conclusions: We found CRF in 38.6 % MGUS patients using estimation from serum cystatin C and in 34.6 % using estimation from serum creatinine. The class of monoclonal immunoglobulin may influence results of glomerular filtration estimated from cystatin C but it does not influence GFR estimated from creatinine. Diabetic patients had not significantly lower GFR than patients without diabetes mellitus. © Ceská lékarská spolecnost Jana Evangelisty Purkyne, Praha 2013.