Oral glucose tolerance test (OGTT) in Ilorin, Nigeria

Abstract

216 patients who presented at the Metabolic Clinic of the University of Ilorin Teaching Hospital, Nigeria, between January 2003 and December 2003 were recruited for this study. Pregnant subjects had an extended oral glucose tolerance test (OGTT) performed according to the National Diabetes Data Group (NDDG) recommended procedure using 100gm glucose loading, while the rest had a standard OGTT performed according to WHO recommended procedure using 75gm glucose loading. Indications were as follows; 34(15.74%) obstetrics, 164 (75.93%) impaired fasting glucose (IFG), 8(3.70%) unexplained retinopathy, 4(1.85%) previous abnormality of glucose tolerance (PAGT), 2(0.93%) steroid therapy and 4(1.85%) for research. Out of the 34 pregnant subjects, 5(14.71%) had a normal OGTT result, 22(64.71%) had impaired glucose tolerance (IGT), 2(5.88%) were diabetic and 5(14.71%) had a flat response. Of the 164 with IFG, 13(7.93%) were normal, 95(57.93%) had IGT, 48(29.27%) diabetic and 8(4.88%) had flat response. 2(25.00%) out of 8 that presented with unexplained retinopathy had DM and the rest 6(75.00%) had IGT. Two (50.00%) of those with PAGT were normal while the rest 2(50.00%) had DM. The two subjects on steroid therapy (100.00%) had IGT. Two (50.00%) of those sent for investigation as part of research had IGT while the rest 2(50.00%) had a flat response. This study shows that about 90% of OGTT requests were made on the basis of IFG and suspected gestational diabetes mellitus (GDM) while no requests were made for unexplained neuropathy, unexplained nephropathy and investigation of hypoglycemia. We conclude that there is under utilization of OGTT in the diagnosis of unexplained neuropathy, unexplained nephropathy and unexplained retinopathy in our center.

Keywords: OGTT, request pattern, diagnostic outcome

The Tropical Journal of Health Sciences Vol. 13(2) 2006: 15-19