[The prognosis and related factors impacting renal response in newly diagnosed multiple myeloma patients with renal impairment].

Objective: To investigate the prognosis and related factors impacting renal response in newly diagnosed multiple myeloma (NDMM) patients with renal impairment. Methods: A total of 375 NDMM patients diagnosed at the Department of Hematology, the First Affiliated Hospital of Nanjing Medical University from August 2012 to April 2022 were retrospectively recruited. Patients were categorized into non-renal impairment group(n=273) and renal impairment group (n=102) according to renal function at initial diagnosis. All patients received≥2 cycles of bortezomib-based induction chemotherapy after admission. The hematological response included stringent complete response (sCR), complete response (CR), very good partial response (VGPR), partial response (PR) and stable disease (SD). The renal responses were defined as CR, PR, minor response (MR) and non-response (NR). General clinical data of the patients were collected, and patients were followed up by telephone. The follow-up deadline was December 3, 2022, and the median follow-up time [M (Q₁, Q₃)] was 42 (22, 61) months. Kaplan-Meier analysis was used to plot the survival curve. The log-rank test was utilized for inter-group comparisons. Multivariate logistic regression modeling facilitated the exploration of associated factors impacting renal response. Results: In the renal impairment group, there were 68 males and 34 females with a median age [M (Q₁, Q₃)] of 64 (58, 69) years. In the non-renal impairment group, there were 149 males and 124 females with a median age of 62 (54, 68) years. Compared with the renal impairment group, the age, lactate dehydrogenase and 24-hour urinary protein quantity were increased, the proportion of patients with light chain M protein and the proportion of patients at the DS-Ⅲ stage, ISS-Ⅲ stage and R-ISS-Ⅲ stage were higher, the hemoglobin level and the proportion of patients receiving autologous hematopoietic stem cell transplantation were lower in the renal impairment group (all P<0.05). In 102 patients with renal impairment, renal responses of CR, PR, MR and NR were obtained in 53 (52.0%), 8 (7.9%), 18 (17.6%), 23 (22.5%) patients, respectively, and the overall response rate was 77.5% (79/102). Kaplan-Meier survival curve revealed that the median progression-free survival (PFS) was 24.0 (95%CI: 18.3-29.7) months in the renal impairment group, which was shorter than 31.0 (95%CI: 24.7-37.3) months in the non-renal impairment group (P=0.003). The median overall survival (OS) was 46.0 (95%CI: 36.5-55.5) months in the renal impairment group, which was shorter than 79.0 (95%CI: 59.9-98.1) months in the non-renal impairment group (P=0.002). Among the renal impairment group, patients with renal response of less than PR exhibited a median PFS of 19.0 (95%CI: 9.7-28.3) months, which was shorter than 28.0 (95%CI: 21.4-34.5) months for those achieving PR or better (P=0.048). The median OS was 31.0 (95%CI: 23.5-38.5) months in renal response with less than PR group, which was also worse than 57.0 (95%CI: 42.8-71.2) months for those who achieved PR or better (P=0.003). The results of multivariate logistic regression showed that hematological response achieving VGPR or better was a factor associated with renal response achieving PR (OR=4.20, 95%CI: 1.20-14.68, P=0.025). Conclusions: The prognosis of NDMM patients with renal impairment is poor. The hematological response with VGPR or better is related to the renal response achieving PR.