Glycaemic control and correlation between estimated average glucose and glycated haemoglobin in diabetic patients seen in a tertiary hospital in Benin City, Nigeria

Diabetes mellitus is on the increase worldwide and in Nigeria, with prevalence ranging from 0.65% in rural Mangu to as high as 11.0% in urban Lagos.  Its prevention, early diagnosis and adequate treatment to prevent morbidity and mortality are essential. Glycated haemoglobin estimation is a marker of glycaemic control and it reflects average plasma glucose over previous eight to twelve weeks. Reporting estimated average glucose along with glycated haemoglobin values may be useful in the assessment of long term glycaemic control of diabetic patients. This work aims to assess glycaemic control in diabetic patients and determine the association between estimated average glucose and glycated haemoglobin values. This work is a retrospective study. Data of 100 diabetic patients (Type 1 and 2) seen in the endocrine outpatient clinic of the University of Benin Teaching Hospital between March 2017 and October 2017 were analyzed. Glycated haemoglobin (HbA1c) assay was done using high performance liquid chromatography (Bio - Rad). Estimated average glucose was derived using Nathan’s regression formula. Good glycaemic control was established at glycated haemoglobin < 7% according to the American Diabetes Association recommendation. Mean age of the subjects was 61.5 ± 14.8 years. Mean fasting plasma glucose, estimated average glucose, glycated haemoglobin in the subjects were 188.6 ± 100.3, 165.4 ± 24.8 mg/dl, 7.4 ± 2.4% respectively. Estimated average glucose showed a strong positive correlation with glycated haemoglobin, which was statistically significant; r = 1.000, p = 0.000.  46% of the subjects had glycated haemoglobin values < 7%, while 54% had values ≥ 7%. Estimated average glucose correlated strongly and significantly with glycated haemoglobin, therefore reporting estimated average glucose along with glycated haemoglobin values may be useful and beneficial in the assessment of long term glycaemic control of diabetic patients. Glycaemic control is yet to be optimal in the study population. Key words: Estimated average blood glucose (eAG), glycated haemoglobin (HbA1c), diabetes mellitus.