Effects of Amyloid Light-Chain Amyloidosis on Clinical Characteristics and Prognosis in Multiple Myeloma: A Single-Center Retrospective Study

Abstract Background: Amyloid light-chain amyloidosis (AL amyloidosis) is commonly associated with multiple myeloma. However, the clinical characteristics and prognosis of symptomatic and smoldering multiple myeloma with AL amyloidosis is not particularly clear.Methods: Patients with symptomatic and smoldering multiple myeloma in the Peking University First Hospital registry from 2010 to 2018 were studied. The clinical and laboratory information were collected from first presentation to death or until the last available clinical follow-up. The patients’ survival and outcomes were analyzed, and the relationships between the clinical parameters and survival were also assessed.Results: Compared with symptomatic multiple myeloma patients without AL amyloidosis, patients with AL amyloidosis had higher incidence of BNP≧700pg/ml (P<0.001), ALP>187.5IU/L (P=0.032) and ALB<25g/L (P<0.001). Similarly, compared with smoldering multiple myeloma patients without AL amyloidosis, patients with AL amyloidosis had higher incidence of BNP≧700pg/ml (P=0.030) and Alb<25g/L (P=0.024). The existence of AL amyloidosis especially the heart involvement was related to shorter long-term survival of symptomatic and smoldering multiple myeloma according to univariate analyses. Renal involvement and gastrointestinal tract involvement had an impact on the prognosis of smoldering multiple myeloma but not on symptomatic multiple myeloma. Cox regression model for overall survival detected BNP≧700pg/ml in symptomatic multiple myeloma having independent prognostic significance (RR=2.455, P=0.004). Interestingly, BNP at diagnosis was significantly correlated with cardiac amyloidosis (r=0.496, P<0.001).Cox regression model for overall survival detected the presence of AL amyloidosis in smoldering multiple myeloma having independent prognostic significance (RR=8.741, P=0.002).Conclusions: AL amyloidosis is an independent poor prognostic factor for not only symptomatic multiple myeloma but also smoldering multiple myeloma is mainly because involvements of important organs especially the heart. AL amyloidosis probablely has a greater impact on the prognosis of smoldering multiple myeloma than symptomatic multiple myeloma.