Assessment of diabetic control by measurement of urinary glycopeptides

The relationship between improvement in diabetic control and changes in levels of glycosylated urinary peptides was investigated. Eight poorly controlled Type 1 (insulin-dependent) diabetic patients were studied as optimal metabolic control was achieved. Mean daily blood glucose values and weekly haemoglobin A1 levels were determined simultaneously. Urinary glycosylated peptide levels fell 50% in 15 days, compared with 23 days for haemoglobin A1. Levels of glycosylated urinary peptides were sensitive to increased mean blood glucose concentrations of 9.72 mmol/l and increased linearly up to 20.0 mmol/l (r = 0.98) when compared with mean blood glucose levels obtained 8-9 days earlier. A similar correlation was found with haemoglobin A1 levels. Levels of glycosylated urinary peptides before and after optimal control were compared, and a decrease of 40% was observed (pre-control: 269 +/- 44 mumol/day, optimal control: 162 +/- 45 mumol/day, mean +/- SEM). The lag time between the fall in mean blood glucose level and the parallel fall in glycosylated urinary peptides was 8-9 days, suggesting that measurement of these compounds may become a useful clinical laboratory technique for monitoring short-term integrated glycaemia in diabetic patients.