Lack of Renal Recovery Predicts Poor Survival in Patients of Multiple Myeloma With Renal Impairment

Background Renal impairment (RI) confers a poor prognosis in multiple myeloma. Reversibility of renal function is associated with improved survival in such patients. Patients in developing countries often present at an advanced stage and renal impairment is present in up to 40% of patients at diagnosis. We studied the renal outcome and survival of these patients with bortezomib-based induction therapy. Materials and Methods It was a single-center prospective study in a tertiary care multi-specialty institute in patients of newly diagnosed multiple myeloma (NDMM) who presented with RI from July 2018 to December 2019. The diagnosis of multiple myeloma was made based on IMWG14 criteria. All patients received bortezomib and or immunomodulatory drug-based triplet or quadruplet induction therapy. Hematological and renal outcomes were assessed as per IMWG 2016 criteria. Results Among 216 consecutive patients of NDMM, RI was seen in 91 (42.2%) patients. The median age of 91 patients was 60 years. (range- 32-80 years). Light chain myeloma was seen in 26% (n = 24) of patients. The median estimated glomerular filtration rate (eGFR) was 15.36 mL/min (3.1-38 mL/min) and a majority of patients were in the advanced ISS stage. (ISS III = 85.7%). Thirty-six (39.5%) patients received hemodialysis at presentation. Renal response was seen in 67 (73%) patients and 20 (out of 36; 55%) became dialysis independent over a median time of 38 days (Range 15-160 days). At a median follow-up of 14.7 months, 30 (33%) patients had died, of which, 14 (15.4%) patients had early mortality (within 2 months of diagnosis). Presence of light chain myeloma and cast nephropathy (definite or probable) were identified as independent predictors of poor renal recovery on multivariate analysis. (HR = 2.841; 95% CI [1.471-5.486], P = .002 for light chain myeloma; HR = 1.859; 95% CI (1.087-3.180); P = .024 for cast nephropathy) Patients with low eGFR at presentation (<12.5 mL/min) were more likely to have persistent renal insufficiency. (HR-3.521; 95% CI (1.856-6.679), P = .000). Patients who attained sustained renal recovery had improved survival as compared to patients in whom renal function failed to improve. (median OS- not reached vs. 8.3 months, P = .000) Achievement of hematological response and independence from hemodialysis was associated with improved survival on multivariate analysis. Conclusion Renal impairment was reversible in almost three-fourths of NDMM patients. achievement of hematological response and hemodialysis independence were independent predictors of improved overall survival in NDMM patients with RI.