Diabetes and problems with blood vessels (vascular disease) can damage the kidney's filter system. The damaged system first leaks small and then large amounts of protein into the urine, and the damaged kidneys eventually fail (this condition is called end-stage renal disease). The affected person may need dialysis or a transplant. Several studies show that treatments, such as angiotensin-converting enzyme (ACE) inhibitors and angiotensin-receptor blockers (ARBs), may prevent worsening of kidney disease in people who already are leaking large amounts of protein in their urine (a condition called macroalbuminuria). Few studies, however, have assessed whether these treatments can prevent kidney disease in people who are not yet leaking large amounts of protein in their urine.