Association between glycated hemoglobin and hematological parameters in patients with type 2 diabetes mellitus: a cross-sectional study.

BACKGROUND: Glycosylated hemoglobin (HbA1c) is a critical biomarker for evaluating long-term glycemic state and diagnosing diabetes mellitus, although hematological abnormalities can affect its clinical interpretation. This study aimed to determine the association of HbA1c with hematological parameters among patients with T2DM; assess associations after adjusting for age and sex; investigate sex-specific differences; and evaluate prevalence of anemia in different glycemic control categories. METHODS: This cross-sectional study evaluated clinical data from 1,278 patients with confirmed T2DM (HbA1c ≥ 6.5%; 726 females, 552 males) aged ≥ 30 years collected between January 2020 and December 2021. Analyses included correlations, age- and sex-adjusted linear regression, interaction testing, analysis of variance, logistic regression, and Holm correction. RESULTS: The mean HbA1c was 8.56 ± 1.80%. Sex-stratified analysis indicated a sex-dependent reversal in the HbA1c-Hct association, with a positive correlation in females (r = 0.106) and a negative correlation in males (r = -0.110); the interaction remained significant after correction (p = 0.035). MCHC was the hematological parameter most strongly associated with HbA1c overall (r = 0.101, adjusted p = 0.002) and remained significant after adjusting for age and sex (β = 0.095, 95% CI 0.034-0.156; adjusted p = 0.014). In males, HbA1c was inversely associated with MCV (r = -0.140, adjusted p = 0.011). The prevalence of anemia was 22.9% and was significantly higher in females than males (27.7% vs. 16.7%, p < 0.001); HbA1c was not associated with anemia (OR = 0.96, 95% CI 0.89-1.04). CONCLUSIONS: These associations were very weak and require prospective confirmation.