Objective:To investigate the clinical features, efficacy and risk factors for the development of anemia in newly-diagnosed multiple myeloma (NDMM) patients with anemia.Methods:A retrospective case-control study was conducted. General data and laboratory findings of 165 NDMM patients hospitalized at the People's Hospital of Qiannan in Guizhou Province and Affiliated Zhongshan Hospital of Dalian University from January 2018 to December 2022 were retrospectively analyzed. The patients were treated with chemotherapy regimens based on at least 2 new drugs including proteasome inhibitors and immunomodulators, and the efficacy was assessed after 4 cycles of treatment. According to peripheral blood hemoglobin (Hb) concentration, patients were divided into anemia group (Hb < 100 g/L) and non-anemia group (Hb ≥ 100 g/L). The general data, hematological indexes, and treatment effects of the two groups were compared. Pearson correlation coefficient was used to analyze the correlation between Hb and hematological indexes; multivariate logistic regression was used to analyze the risk factors for the occurrence of anemia in patients with NDMM; anemia defined by Hb was used as the gold standard, and receiver operating characteristic (ROC) curve was used to analyze the effect of the above risk factors for anemia on judging the occurrence of anemia in MM patients.Results:There were 120 cases in the anemia group with a median age [ M ( Q1, Q3)] of 64 years old (59 years old,74 years old), including 61 (50.8%) males and 59 (49.2%) females, and 45 cases in the non-anemia group with a median age of 61 years old (54 years old, 68 years old), including 27 (60.0%) males and 18 (40.0%) females. The age of patients and the proportion of patients with Durie-Salmon (DS) stage Ⅲ, international staging system (ISS) stage Ⅲ, renal impairment, and hypercalcemia in the anemia group were higher than those in the non-anemia group (all P < 0.05); peripheral blood platelet counts and serum albumin concentrations in the anemia group were lower than those in the non-anemia group, and the differences were statistically significant (all P < 0.05); the concentrations of globulin, the erythrocyte sedimentation rate (ESR) and serum β 2-microglobulin (β 2-MG) concentration, creatinine concentration, uric acid concentration, serum corrected calcium concentration, and the proportion of abnormal plasma cells in bone marrow in the anemia group were higher than those in the non-anemic group, and the differences were statistically significant (all P < 0.05). The objective remission rate in the anemia group was lower than that in the non-anemia group [42.5% (51/120) vs. 71.1% (32/45), χ2 = 10.72, P = 0.001]. Pearson correlation coefficient showed that Hb concentration was positively correlated with serum albumin concentration and platelet count ( r values were 0.569 and 0.229, both P < 0.05), and it was negatively correlated with ESR, globulin, β 2-MG, creatinine, uric acid, serum corrected calcium concentration and the proportion of abnormal plasma cells in bone marrow ( r values were -0.318, -0.465, -0.373, -0.230, -0.303, -0.248, and -0.368, all P < 0.05). Multivariate logistic regression analysis showed that the increased serum albumin concentration was the independent protective factor for the occurrence of anemia in patients with NDMM ( OR = 0.891, 95% CI: 0.798-0.994, P = 0.039), and the increased proportion of abnormal plasma cells in bone marrow was the independent risk factor for the occurrence of anemia in patients with NDMM ( OR = 0.941, 95% CI: 0.908-0.974, P = 0.001). ROC curve analysis showed that the areas under the curve for the occurrence of anemia in NDMM patients based on serum albumin concentration and the proportion of abnormal plasma cells in bone marrow were 0.813 (95% CI: 0.743-0.882, P < 0.001) and 0.792 (95% CI: 0.715-0.870, P < 0.001). Conclusions:Compared with NDMM patients without anemia, NDMM patients with anemia have abnormalities in several tests and poor treatment outcomes, and these patients should be actively corrected for anemia and hypovitaminosis, and clear plasma cell load as early as possible in conjunction with antimyeloma therapy.