Sex and age affect agreement between fasting plasma glucose and glycosylated hemoglobin for diagnosis of dysglycemia

Abstract

Aim: To assess agreement between fasting plasma glucose (FPG) and hemoglobin A_1c (HbA1c) levels for diagnosis of dysglycemia (diabetes and risk of diabetes), overall and depending on clinical characteristics.

Methods: The study enrolled 1020 adult subjects without drug-treated diabetes who underwent a laboratory test at a Spanish health care center. The criteria for dysglycemia of the American Diabetes Association were used. A logistic regression analysis was used to predict de novo diagnosis of dysglycemia based on sex, age, body mass index, anemia, and iron levels.

Results: Overall prevalence of dysglycemia was 28.04%, and was identified by FPG only in 13.63% of subjects, by both FPG and HbA1c in 7.65%, and by HbA1c only in 6.76% (de novo diagnoses). Independent predictors of de novo diagnoses based on HbA1c were female sex (odds ratio [OR]: 2.119, 95% confidence interval [CI]: 1.133-4.020; p<0.020), age (OR for 42-56 years: 2.541, 95% CI: 0.634-17.140; OR for ≥57 years: 5.656, 95% CI: 1.516-36.980; overall p<0.007), and serum ferritin levels (borderline significance).

Conclusions: In this study population, agreement between FPG and HbA1c for diagnosis of dysglycemia was poor, with FPG being the test that identified more subjects. De novo diagnoses based on HbA_1c were more common in females and increased with age.

Keywords: Age; Diabetes mellitus; Edad; Fasting plasma glucose; Glucemia basal; Hemoglobin A1c; Hemoglobina A1c; Sex; Sexo.