#6719 ACUTE KIDNEY INJURY AND MULTIPLE MYELOMA-THE ROLE CYTOGENETICS: A COHORT STUDY
Authors: Rodrigues Natacha , Branco Carolina , Sapinho Guilherme , Vieira Joana , Silva Hugo , Martins Carlos , Esteves Graça , Raposo João , Lopes José António 
Published: June 2023

Abstract

Background and Aims
Multiple myeloma(MM) is the 2nd most common haematological neoplasm and a largely heterogeneous malignancy in what regards cytogenetics, clinical presentation, therapy response and overall survival. Renal impairment related to MM is known to be diagnosed in at least 50% of patients during the course of this disease. Recent studies have shown an association between high-risk cytogenetic abnormalities(CA) with lower disease-free survival and lower overall survival. However, there is still scarce knowledge in what regards the kidney implications of MM CA. The purpose of this study is to identify an association between MM cytogenetic profile and acute kidney injury(AKI) at presentation.

Method
This was a single-centre retrospective cohort study of all adult patients diagnosed with MM between Jan./2018-Dec./2021 in a tertiary care university hospital in Lisbon. Diagnosis of MM was made according to the International Myeloma Working Group criteria. Patient variables were collected from individual clinical records. Categorical variables were described as the total number and % and continuous variables as median(P25-P75). Normally distributed continuous variables were compared with the Student-t-test, non-normally distributed continuous variables with the Mann-Whitney U-test and categorical variables with the chi-squared test. A multivariable backward stepwise regression model was performed to investigate predictors for AKI. Statistical significance was defined as p&lt;0.05. Analyses were performed with the statistical software package STATA 16.0.

Results
114 patients were included[median age 69.8±11.4 years, 48.1% male, 90.4% caucasian]. 61.5% had hypertension, 21.2% diabetes and 33.9% CKD with baseline GFR of 75.2(49.5-92.3)mL/min/1.73m2. 25% were on RAAS inhibitors, 5.8% on NSAID and 9.6% on bisphosphonate. The most common heavy chain was IgG(58.8%), the most common light chain was Kappa(52.4%) and 12.8% were isolated light chain-MM. 56.5% had a Revised International Staging System(R-ISS) of 2. Median serum M component was 4.5(2.8-7.9)g/dL, dFLC 247.8(48.9-1059.2) mg/L and plasma cells in bone marrow(BM) aspirate 39.0(15.5-67.0)%. 15.4% had hypercalcaemia, 68.9% Bence Jones protein, 3.8% secondary amyloidosis and 18.3% extramedulary disease. 38 patients had CA: 36.5% primary, 35.6% secondary and 33.7% high risk CA. Most patients were treated with proteasome inhibitors(75.0%), 26.9% were submitted to BM transplant and 59.2% had a complete or very good partial response to treatment. 13(12.5%) relapsed and 26(25.0%) died. AKI was present in 31.1% of patients and 11.7% needed renal replacement therapy.On univariable analysis, variables with impact on AKI were diabetes (34.3% vs 15.5%, p = 0.03), CKD (62.5% vs 21.1%, p&lt;0.001), hypercalcemia (28.1% vs 9.9%, p = 0.018), higher R-ISS (p&lt;0.001), beta 2-mycroglobulin (p&lt;0.001), % of plasma cells in BM aspirate (p = 0.002) and dFLC (p = 0.01), lower baseline GFR (p&lt;0.001) and the presence of CA (53.1% vs 28.2%, p = 0.015), primary CA (53.1% vs 28.2%, p = 0.015) and high-risk CA (46.9% vs 28.2%, p = 0.064). On multivariable analysis, the presence of CA[OR 3.094 (1.018-9.403), p = 0.046] and previous CKD[OR 8.069(2.430-26.796), p = 0.001] showed an independent association with AKI at presentation.

Conclusion
Our study suggests there is an association between CA and AKI at presentation, which may implicate a worse overall survival, have treatment implications and highlights the need for prevention and early diagnosis.MM cytogenetics is being studied since the 2000s and research is still on going in the attempt of creating a MM profile that can guide prevention, treatment and predict outcomes. It is known that renal impairment in MM particularly at diagnosis is associated with lower overall survival. However, to the best of our knowledge, the potential association between cytogenetic profile and AKI has not been thoroughly studied.