MO198IMPACT OF KIDNEY FUNCTION ON THE EVOLUTION OF MONOCLONAL GAMMOPATHIES OF UNCERTAIN SIGNIFICANCE

Abstract

Abstract Background and Aims Monoclonal gammopathies of uncertain significance (MGUS) are very prevalent, but neoplastic transformation barely reaches 1% per year. Renal involvement in the course of a MGUS is a risk factor for complications. The objective of our study is to determine the prognosis of MGUS that present renal deterioration during their evolution. Method In the present retrospective cohort study, MGUS cases from our center were included. Baseline epidemiological and comorbidity data were collected (including renal function and hematological parameters). At 6 and 12 months, data on renal function and proteinuria were collected. During the follow-up, fatal events and the need for renal replacement therapy (RRT) were recorded as a combined endopoint. Associated factors to this combined endpoint were evaluated. Results One hundred twenty patients (47% women, age 81±9 years.) with diagnosis of MGUS were included. Of these, 61 (51%) had renal involvement at the time of diagnosis and 16 (13%) had an estimated glomerular filtration rate (eGFR) of less than 60 ml/min/1.73m2 during follow up. Associated factors with presenting eGFR less than 60 ml/min/1.73m2 were hypertension (p=0.001), peripheral vascular disease (p=0.05), age (p=0.05), Charlson comorbidity index (p<0.001), β2microglobulin (p = 0.002), baseline proteinuria (p <0.001) and baseline renal function (p <0.001). During follow-up (median 41 [20-60] months), 34 patients (28%) presented the combined event (8 required RRT and 28 died). The presence of an eGFR less than 60 ml /min/1.73m2 during the first year of follow-up was associated with the combined event (p = 0.028) (Figure 1). In a multivariate model adjusted for age, sex and baseline CKD, the presence of a determination of eGFR lower than 60 ml/min/1.73m2 was an independent predictor for the combined event (HR 3.9 [95% CI 1.4-11.3], p = 0.009). In patients without chronic kidney disease at baseline, 13 (22%) combined events were reported. The incidence of a determination of eGFR lower than 60 ml/min/1.73m2 was associated with the combined event during follow-up (p = 0.012). In a multivariate model adjusted for age and Charlson index, presenting an eGFR lower than 60 ml/min/1.73m2 was an independent predictor for the combined event (HR 6.7 [95% CI 1.7-26.7], p = 0.007) (Figure 2) Conclusion Among patients with MGUS, the presence of eGFR lower than 60 ml/min/1.73m2 is independently associated with a higher incidence of RRT and/or mortality.