Markers of microvascular complications in insulin dependent diabetes.

creening for early markers of micro-vascular disease is now generally recommended from around the age of 10 years in children with type 1 diabetes mellitus (TIDM). Annual assessment should include direct fundal examination or fundus photography, monitoring of arterial blood pressure (BP), and measurement of urinary albu-min excretion. The basis of all screening programmes is that those most at risk can be correctly identified and that there should be appropriate and effective interventions. The value of retinal screening is beyond doubt as the detection of early preproliferative or prolifera-tive retinopathy may lead to successful intervention with laser therapy, but such events are rare before the age of 18 years. The evidence supporting screening for other markers of microvascular disease, such as microalbuminuria (MA) and hypertension is more contentious and this is the subject of the current review. Symptomatic autonomic or sensory ne-phropathy is relatively rare in children and adolescents and this will not be discussed further. The decision to introduce screening at age 10 years reflects the influence of puberty on the risk for microvascular disease. Several cross sectional studies and at least two large longitudinal studies (the Berlin Retinopathy Study and the Oxford Regional Prospective Study (ORPS)) have shown that microvascular complications are rare before puberty. 1 2 Puberty confers a three-to fourfold increase in risk of MA after adjusting for other major risk factors such as diabetes duration, HbA1c, and gender. 1 3 Prepu-bertal duration of diabetes may contribute to the risk of MA, but this only becomes evident after the onset of puberty. 1 Contrary to historical belief, MA is not rare 4 and may progress 5 within the first five years after the diagnosis of TIDM in pubertal subjects. 4 5 Puberty also increases the risk of retinopathy by approximately threefold 6 ; as a result the median duration of diabetes when retin-opathy is detected is significantly shorter in subjects of pubertal age at diagnosis when compared to those where diabetes is diagnosed before puberty. 2 Preprolif-erative retinopathy may be detected, using fundus photography, in pubertal subjects as young as 11 years of age and at seven years duration of diabetes. 7 MICROALBUMINURIA The term MA denotes increases in albu-min excretion rates outside of the normal range, but too low to register on the normal clinic albusticks. The current consensus definition is that the urinary albumin excretion rate should be more than 20 µg/min and less …