Relationship of glycated hemoglobin, and fasting and postprandial hyperglycemia in type 2 diabetes mellitus patients in Malaysia

AIMS/INTRODUCTION: Studies on the relative contributions of fasting and postprandial hyperglycemia (FH and PPH) to glycated hemoglobin (HbA(1c)) in patients with type 2 diabetes have yielded inconsistent results. We aimed to assess the relationship by using continuous glucose monitoring in a multi‐ethnic cohort. MATERIALS AND METHODS: A total of 100 adults with type 2 diabetes were assessed with 6‐day continuous glucose monitoring and HbA(1c). Area under the curve (AUC) ≥5.6 mmol/L was defined as AUC(TOTAL). AUC equal to or greater than each preprandial glucose for 4‐h duration was defined as AUC(PPH). The total PPH (AUC(TPPH)) was the sum of the various AUC(PPH) (.) The postprandial contribution to overall hyperglycemia was calculated as (AUC(TPPH) / AUC(TOTAL)) × 100%. RESULTS: The present study comprised of Malay, Indian, and Chinese type 2 diabetes patients at 34, 34 and 28% respectively. Overall, the mean PPH significantly decreased as HbA(1c) advanced (mixed model repeated measures adjusted, beta‐estimate = −3.0, P = 0.009). Age (P = 0.010) and hypoglycemia (P = 0.006) predicted the contribution difference. In oral antidiabetic drug‐treated patients (n = 58), FH contribution increased from 54% (HbA(1c) 6–6.9%) to 67% (HbA(1c) ≥10%). FH predominance was significant in poorly‐controlled groups (P = 0.028 at HbA(1c) 9–9.9%; P = 0.015 at HbA(1c) ≥10%). Among insulin users (n = 42), FH predominated when HbA(1c) was ≥10% before adjustment for hypoglycemia (P = 0.047), whereas PPH was numerically greater when HbA(1c) was <8%. CONCLUSIONS: FH and PPH contributions were equal in well‐controlled Malaysian type 2 diabetes patients in real‐world practice. FH predominated when HbA(1c) was ≥9 and ≥10% in oral antidiabetic drug‐ and insulin‐treated patients, respectively. A unique observation was the greater PPH contribution when HbA(1c) was <8% despite the use of basal and mealtime insulin in this multi‐ethnic cohort, which required further validation.