Dependence of Retinopathy (and other Complications) on Glycaemic Control and on Weight over 5/10 Years from Diagnosis of Type II Diabetes

Glycosylated haemoglobins and weights were recorded for 200 consecutive diabetic clinic attendere seen yearly for 5 years, 76 of whom were also seen up to 10 years from diagnosis of type 2 diabetes, representing 1380 patient years. Weight fluctuation (≥3 kg) was associated with increased final prevalence of hypertension, macroalbuminaemia and a raised creatinine (P≤ 0.002) but this relationship was abolished by correction for higher initial weight. Average giycaemia over 5/10 years [itself related to initial weight in women on tablets (N=53) but not others, and to waist but not waist/hip ratio], correlated with prevalence and severity of retinopathy (N=200; r=0.38, P≤0.0006) seen also in the subgroup of patients on tablets (N=145, P≤0.006). At HbA1 levels ≥10.5% an increased prevelance of retinopathy was seen in those on insulin (W=37, P≤0.001) and an increased prevalence of peripheral vascular disease was seen in men but not women (x2=2.87, P≤0.01) as well as in the prevalence of neuropathy. These findings suggest that good glycaemic control is of value in type 2 diabetes and less easily achieved in obesity.

Glycosylated Haemoglobins: Biochemical Evaluation and Clinical Utility

A review is given of the biochemical background of the glycosylated haemoglobins, their methods of determination, and their clinical significance. Special attention is paid to the sample preparation. For all methods except the colorimetric TBA-method, the removal of the labile pre-HbA1c fraction is essential. Under proper conditions, high-performance liquid chromatography, agar-gel electrophoresis and affinity chromatography are suitable methods for use in the clinical laboratory for the estimation of HbA1c and HbA1. However, the colorimetric TBA-method must be considered to be the method of choice. The clinical utility of the test is stressed with special respect to the management of diabetic pregnancies, the control of home-monitoring of blood glucose, and the objective measurement of the effect of changing diabetic therapy.