Glycated Haemoglobin Levels in Patients with Diabetes in One General Practice over a 10-year Period

The aim of the study was to evaluate the level of control, as reflected by HbA_1c, in patients with diabetes attending one general practice over a 10-year period. The study was based in one general practice in South Tyneside, UK and consisted of an analysis of HbA_1c values of all patients with diabetes attending the practice between 1983 and 1992. HbA_1c levels were analysed and are presented as multiples of the standard deviation above the mean. In the practice 256 patients with non-insulin-dependent diabetes mellitus (NIDDM) and 76 with insulin-dependent diabetes mellitus (IDDM), attended for a total of 1596 doctor/patient contacts in the diabetic clinic over 10 years. The prevalence of diabetes was 1.9%. Over the course of the clinic, in any one year, 25% of patients with NIDDM and 55% with IDDM had levels of HbA_1c above those thought to be associated with increased risk of microvascular complications. Significant reduction in glycated haemoglobin (HbA_1c) occurred in the first year after diagnosis (p < 0.01) and after changing treatment from diet alone to diet and oral hypoglycaemic agents (p < 0.001). We conclude that a large proportion of patients within this population had levels of glycaemic control that put them ‘at increased risk’.