#6394 ACUTE KIDNEY INJURY IN MYELOMA WITH HIGH LIGHT CHAIN PRODUCTION: A 10-YEAR EXPERIENCE
Authors: Delgado-Palacios Jesús Domínguez , Salazar Sara Huertas , Rincón María Muñiz , Pérez Virginia López de la Manzanara , Romero Natividad Calvo , Almudena Juez Del Pozo , Meneses Arianne Aiffil , Herrero José , Fructuoso Ana Sanchez 
Published: June 2023

Abstract

Background and Aims
In multiple myeloma (MM), a high serum light chain (LC) concentration significantly increases the probability of developing cast nephropathy. The use of high cut-off (HCO) hemodialysis (HD) membranes has not been clearly shown to be effective in 2 large European studies (MYRE and EuLITE) in terms of improved prognosis. Therefore, their use is currently controversial. We want to review our experience, in the last 10 years, of patients with Acute Kidney Injury (AKI) in the context of MM in progression with high circulating LC: whether or not any HD technique has been performed and what factors may have had an impact on kidney and patient survival.

Method
We reviewed all cases of MM flare or progression, with LC &gt;1000 mg/L and AKI, evaluated by our service between May 2012 and May 2022 (N = 20). We collected data on baseline renal function, laboratory tests, type and amount of light chain and monoclonal component, whether or not HD was performed, type of technique, evolution of kidney function and mortality.

Results
We counted 60% males, median age of 76.5 years (69.5-83.0), and baseline creatinine of 1.30 (0.94-1.66) with an estimated glomerular filtration rate (eGFR) of 52 mL/min (35-58). At the time of AKI, the median obtained data were: peak creatinine 4.6 mg/dL (4.1-6.0), Hb 8.8 g/dL (8.3-11.6), albumin 3.6 mg/dL (3.1-4.1), calcemia 10.1 mg/dL (9.5-11.5), blood monoclonal component of 0.80 mg/dL (0.36-2.22) and serum LC of 5. 480 mg/L (2,143-11,825). In 9 cases the myeloma was CL kappa-producing and in 11 cases CL lambda-producing. In 9 of the 20 cases (45%) the patient died within 6 months. HD was performed in 11 cases: 7 with HCO membrane, 2 with polymethylmethacrylate (PMMA) and 2 with conventional technique. Of the 7 patients dialyzed with HCO, 3 died in &lt;6 months (43%) and 2 of them (29%) were also HD-dependent at the time of death. The 2 patients dialyzed with PMMA had eGFR&gt;30 mL/min at 6 months after the episode. In contrast, the 2 patients who underwent conventional HD died in &lt;6 months without recovery of renal function. Of the 9 patients who did not undergo HD, 4 had optimal recovery of renal function (eGFR&gt;45 mL/min) but 2 of them died in &lt;6 months (50%). Of the remaining 5: 2 died in &lt;6 months (40%), progression to end-stage CKD was observed in 2 cases (HD was not performed and one of them died in &lt;1 year), and the remaining patient remains alive with eGFR&gt;20 mL/min at 2 years of follow-up. Concerning chemotherapy (QT), 13 patients were treated with bortezomib (12 in 1st line), 4 with lenalidomide and only 1 case was not treated. Of 8 patients who achieved remission with chemotherapy (40% of the total), 7 remained alive at 2 years of follow-up (87.5% of them) and did not require HD, and only 1 of them died at 1 year after a new recurrence (despite HD being implemented). Although statistical significance was not reached due to the small sample size, we did observe a statistical trend towards a higher risk of death at 6 months in patients with peak creatinine &gt;5 mg/dL (p = 0.078), albuminemia&lt;3.5 mg/dL (p = 0.078) and lambda-type LC (p = 0.064).

Conclusions
The use of HCO membranes has not seemed to influence kidney and patient prognosis. In contrast, remission after chemotherapy appears to be the most important determinant of patient survival. Recovery of kidney function was not related in this review to increased patient survival. Analytical parameters such as peak creatinine, hypoalbuminemia and type and amount of circulating LC could be studied as prognostic factors in this entity.