[Changes and clinical significance of erythrocyte lifespan in megaloblastic anemia]

Objective: To investigate the lifespan of erythrocytes in megaloblastic anemia (MA) patients. Methods: A prospective cohort study analysis. Clinical data from 42 MA patients who were newly diagnosed at the Department of Hematology, Lanzhou University Second Hospital from January 2021 to August 2021 were analyzed, as were control data from 24 healthy volunteers acquired during the same period. The carbon monoxide breath test was used to measure erythrocyte lifespan, and correlations between erythrocyte lifespan and laboratory test indexes before and after treatment were calculated. Statistical analysis included the t-test and Pearson correlation. Results: The mean erythrocyte lifespan in the 42 newly diagnosed MA patients was (49.05±41.60) d, which was significantly shorter than that in the healthy control group [(104.13±42.62) d; t=5.13,P=0.001]. In a vitamin B₁₂-deficient subset of MA patients the mean erythrocyte lifespan was (30.09±15.14) d, and in a folic acid-deficient subgroup it was (72.00±51.44) d, and the difference between these two MA subsets was significant (t=3.73, P=0.001). The mean erythrocyte lifespan after MA treatment was (101.28±33.02) d, which differed significantly from that before MA treatment (t=4.72, P=0.001). In MA patients erythrocyte lifespan was positively correlated with hemoglobin concentration (r=0.373), and negatively correlated with total bilirubin level (r=-0.425), indirect bilirubin level (r=-0.431), and lactate dehydrogenase level (r=-0.504) (all P<0.05). Conclusions: Erythrocyte lifespan was shortened in MA patients, and there was a significant difference between a vitamin B₁₂-deficient group and a folic acid-deficient group. After treatment the erythrocyte lifespan can return to normal. Erythrocyte lifespan is expected to become an informative index for the diagnosis and treatment of MA.