[Mean corpuscular volume ≤100 fl was an independent prognostic factor in patients with myelodysplastic syndrome and bone marrow blast<5 percent].

To explore the prognostic effects of mean corpuscular volume (MCV) in patients with myelodysplastic syndromes (MDS) . 321 newly diagnosed, untransfused primary MDS patients who administered from December 2009 to December 2017 were enrolled. The association of MCV with prognosis and several clinical features and genetic mutations were analyzed. Patients were divided into MCV≤100 fl (=148) and MCV>100 fl (=173) cohorts. Median overall survival of patients with MCV≤100 fl was shorter than their counterparts (27 months 72 months, <0.001) . In subgroup analysis, MCV≤100 fl patients had worse survivals in bone marrow blast <5% cohort (34 months not reached, =0.002) , but not so in ≥5 % cohort (17 months 20 months, =0.078) . MCV≤100 fl was still an independent adverse variable (=1.890, 95% 1.007-3.548, =0.048) after adjusting for clinical and laboratory variables and mutation topography in bone marrow blasts<5% cohort. In bone marrow blasts<5% cohort, patients with MCV≤100 fl had higher hemoglobin levels [90 (42-153) g/L 78.5 (28-146) g/L, =0.015].The proportions of Revised International Prognostic Scoring System (IPSS-R) high/very high risks and poor/very poor IPSS-R karyotypes were higher in MCV≤100 fl cohort (28.8% 10.8%, =0.003; 24.7% 12.9%, =0.049) . MCV≤100 fl cohort had more genetic mutations than those with MCV>100 fl though without significance (0.988 0.769, =0.064) . Mutated SF3B1 was less frequently in MCV≤100 fl cohort (4.7% 15.4%, =0.018) . MCV≤100 fl was an independent adverse variable after adjusting for clinical and laboratory variables and mutation topography in MDS patients with bone marrow blasts<5%.