THE IMPACT OF HYPERTENSION AND ANTIHYPERTENSIVE TREATMENT ON THE COURSE AND PROGNOSIS OF DIABETIC NEPHROPATHY

The primary cause of arterial hypertension and of the increased morbidity and mortality in patients with insulin-dependent diabetes mellitus (IDDM) is diabetic nephropathy. About 35% of IDDM patients develop persistent albuminuria, an irreversible decline in the glomerular filtration rate and elevated blood pressure which collectively contribute to the clinical syndrome of diabetic nephropathy. The excess mortality of IDDM patients with nephropathy is 80-100 times greater than that of an age- and sex-matched non-diabetic population. Diabetic nephropathy is the single most important cause of end-stage renal disease in the Western world, accounting for over a quarter of all such cases. Blood pressure elevation is a frequent finding, even in the early stages of diabetic nephropathy. Elevated blood pressure accelerates diabetic nephropathy, while an effective blood pressure reduction delays the progression of nephropathy and reduces albuminuria. A reduction in glomerular capillary hydraulic pressure may be the crucial factor. All previous reports dealing with the natural history of diabetic nephropathy have demonstrated a cumulative death rate of between 50% and 77% 10 years after the onset of nephropathy. Effective antihypertensive treatment has reduced this rate to 15-20%.