Pattern of utilisation of oral glucose tolerance test: the experience of Aminu Kano Teaching Hospital, Kano

Abstract

Oral glucose tolerance test (OGTT) is the gold standard test for the diagnosis of type 2 diabetes mellitus (DM). It is considered as the oldest dynamic function test in clinical practice and has several advantages over other plasma-based tests for diagnosis of type 2 DM, notably random plasma glucose (RPG) and fasting plasma glucose (FPG). For instance, it is the only means through which diagnosis of impaired glucose tolerance can be made, and has a higher diagnostic yield compared to FPG. There is paucity of data on the utilization of OGTT particularly in northern Nigeria. This study therefore aimed to determine the utilization of OGTT in a tertiary Hospital in Kano, Northwestern Nigeria. This was a retrospective study carried out in Aminu Kano Teaching Hospital between January, 2013 and December, 2014. Following ethical approval, Hospital records of all clients who had OGTT in Chemical Pathology department of the Hospital were retrieved. The OGTTs were done using the 75g, 120 Minutes as recommended by WHO. Plasma Glucose were analyzed using quantitative glucose oxidase method described by Trinder. Data obtained were entered into Microsoft Excel and analyzed using statistical package for social sciences (SPSS) version 20.About 335 OGTTs were performed during the study period but 312 were selected. Majority of the clients were females, 290 (92.9%), aged between 20-39 years (74.0%). About 2/3rd of the clients 224 (78.5%) were pregnant women referred from antenatal clinic due to previous history of Gestational Diabetes  Mellitus (GDM), previous macrosomic baby, and unexplained intra uterine foetal death. Non-obstetric indications for OGTT encountered were obesity, impaired fasting glycaemia and suspected acromegaly. Majority of clients who had OGTT were pregnant women who were referred for obstetric indications. Previous history of GDM was the commonest indication for OGTT. There was under-utilization of OGTT for non-obstetrics medical indications.

Keywords: OGTT, Diabetes mellitus, Gestational Diabetes, Nigeria