Primary author: Charmia Kim G. Balansag, M.D.
Co-author: Ceryl Cindy Tan, M.D.
Chong Hua Hospital, Department of Internal Medicine
Section of Endocrinology, Diabetes and Metabolism
Introduction: The prevalence of Pre-diabetes and Diabetes Mellitus Type 2 among Filipinos exceeds 20%. Progressive loss of insulin sensitivity can occur with fasting blood sugar (FBS) starting 90mg/dl. Studies among Asians with pre-diabetes show a higher prevalence of T2DM diagnosed by 75g Oral Glucose Tolerance Test (OGTT). 75g OGTT is the gold standard but remains underutilized. This study aims to determine the FBS and HbA1c cut-off that can accurately predict pre-diabetes and T2DM along with the associated risk factors.
Methodology: This cross-sectional study was conducted in the outpatient departments of 2 hospitals in Cebu City. Ninety-five adult Filipinos with risk factors for T2DM were enrolled. FBS, HbA1c and 75g OGTT taken and test performance computed with a P-value <0.05 considered significant. ROC curve was computed for the optimal FBS and HbA1c threshold.
Results and Discussion: Pre-diabetes or T2DM was prevalent among 66% of participants. Among those with normal FBS, 40% were re-classified as pre-diabetes or T2DM based on HbA1c and/or OGTT levels. For those with normal HbA1c levels, 45% had abnormal FBS and/or OGTT results. Using 75g OGTT, 23% reached levels indicative of T2DM but had normal or impaired fasting glucose (IFG) while this was found in 20% with pre-diabetic levels of HbA1c. HbA1c was found to be more accurate than FBS.
Conclusion: Performing 75g OGTT for high risk Filipinos with FBS ≥94.2 mg/dL or HbA1c ≥5.6% is highly predictive of a change in glucose tolerance status to pre-diabetes while an FBS ≥ 106 mg/dl or HbA1c ≥ 5.8% is predictive of T2DM. Lower cut-off levels promote earlier detection and preventive measures.
Recommendation: Anemia as confounding factor for HbA1c sensitivity should be investigated. Cost-effectiveness analysis are also recommended.
