Predictors of plasma cell disorders among African American patients: a community practice perspective

Abstract

African Americans have two- to three-fold higher incidence of multiple myeloma and MGUS compared to other ethnic groups in the USA. Some physicians often perform diagnostic evaluations for plasma cell disorders (PCD) in African American patients on the basis of hematological abnormalities (thrombocytopenia, leucopenia, etc.) even in the absence of traditional triggers such as anemia, renal impairment, hypercalcemia, hyperglobulinemia, and lytic bone disease. Whether these nontraditional triggers have any significant association with PCD in African American population is not known. In addition, whether this approach could detect more asymptomatic PCD than black population prevalence is questionable. Moreover, the association between traditional triggers and PCD particularly in blacks has not been clearly delineated. Hence, we have carried out a retrospective study in an attempt to answer these questions. Two hundred fifty-four patients were eligible. Multiple myeloma workup based on parameters other than traditional triggers did not detect more asymptomatic PCD than what is expected of black population prevalence (p = 0.19). Of traditional triggers, the finding of only anemia or hyperglobulinemia seemed to be nonspecific in black population (p = 0.17 and 0.85, respectively). However, the presence of serum creatinine >2mg/dL or corrected serum calcium >10.5mg/dL or a combination of traditional triggers appeared to be strongly predictive of PCD (odds ratio of 6.9, 4.2, and 3, respectively). The number of trigger variables was positively correlated with the likelihood of PCD (p < 0.001). Light-chain-only PCD, renal disease, and abnormal free light chain ratio seemed to be higher in black patients than their white counterparts.