Circadian changes in blood pressure and their relationships to the development of microalbuminuria in type 1 diabetic patients.

Diabetic nephropathy in type I diabetic patients, as it is currently understood, progresses in a stepwise fashion from normoalbuminuria to microalbuminuria, then to overt proteinuria and progression to chronic renal failure, and ultimately to end-stage renal disease. The role of early blood pressure changes in relation to diabetic nephropathy is now better understood in light of recent data using ambulatory blood pressure monitoring as a means to monitor blood pressure changes noninvasively throughout the day. Cross-sectional studies with type I diabetic patients with microalbuminuria have shown that the normal nocturnal blood pressure often fails to fall normally during sleep. The question of which comes first, microalbuminuria or a rise in blood pressure in patients with type I diabetes, was recently addressed in a prospective study. An increase in systolic blood pressure during sleep precedes the development of microalbuminuria and may play a causative role in its development.