Application of the CO breath test to explore the reversibility of hyperglycemia's impact on erythrocyte lifespan

Hyperglycemia can shorten red blood cell (RBC) lifespan, leading to incorrectly measured glycated hemoglobin (HbA1c) values. Correcting for the impact of the RBC lifespan on HbA1c is a critical issue in clinical practice. Before establishing a generally accepted correction formula to account for the impact of RBC lifespan on HbA1c, it is necessary to investigate the duration necessary to emake the hyperglycemia-induced RBC lifespan shortening reverse to normal. This longitudinal clinical trial examined the RBC lifespan in 31 hospitalized patients with type 2 diabetes mellitus by measuring the concentration of exhaled endogenous carbon monoxide. The 31 non-smoking patients with type 2 diabetes were all admitted due to blood glucose (BG) imbalance, and their RBC lifespan was tested at admission, discharge (after ∼2 weeks of intensive glycemic control), and 3 months after discharge. During the period from admission to three months after discharge, RBC lifespan significantly increased in the patients as they underwent drug treatment to control BG (P< 0.05) effectively. HbA1c, fasting plasma glucose, and 2 h postprandial glucose decreased significantly. This study found that (i) a shortened RBC lifespan caused by hyperglycemia is reversible, and (ii) the time required for this reversal is three months of effective drug treatment to control BG.