The Detection of Postprandial Hypoglycemia with 5-Hour Oral Glucose Tolerance Test

Postprandial hypoglycemia (PH) is a poorly understood phenomenon. Five-hour oral glucose tolerance test (5-OGTT) is often a useful laboratory investigation to understand and establish a diagnosis of PH. The aim of this study is to present the patterns observed during 5-OGTT performed in cases with PH in a tertiary hospital in Nepal.

5-OGTTs were performed on 52 patients who complained symptomatic postprandial neuroglycopenic symptoms, at the Nepal Medicity hospital during the period of 2 years from 2017 to 2019. The anthropometry, medical history, serum glucose; insulin and cortisol were obtained. The homeostatic model assessment score for insulin resistance (HOMA-IR) based on fasting glucose and insulin levels were calculated. Data was analyzed using SPSS (Version 20.0).

21 (40.4%) patients out of 52 developed hypoglycemia [blood glucose < 55mg/dl (3.1mmol/L)], among them nine patients developed hypoglycemia at 3 hours, 11 at 4 hours and one at 5 hours post glucose load. The fasting insulin level in patients who developed hypoglycemia was 12.1 ± 5.8 μU/ml compared to the insulin level analyzed at the point of hypoglycemic episode which was 6.4 ± 1.8 μU/ml, P<0.005.

The level of insulin is disproportionately high in the setting of hypoglycemia where it was expected to be nearly absent. The disturbance in physiological mechanism between insulin sensitivity and insulin secretion may be the possible cause of PH.