Relative likelihood of ROR and RCR in Kd-treated vs Vd-treated patients. IRRs and 95% CIs were calculated for ROR and RCR, using multivariate Cox proportional hazard models adjusted for the following baseline covariates: age, sex, race, ECOG PS, ISS stage, baseline renal function, bortezomib use in the first line, time from MM diagnosis to treatment line initiation, use of IV bisphosphonates, and baseline measurements of serum calcium, serum free light-chain ratio, LDH, and whole-blood hemoglobin.