RATIONALE K Patients with diabetes and microalbuminuria are at increased risk of kidney failure and cardiovascular events. K ACE-Is and ARBs reduce the level of urine albumin in patients with diabetes and microalbuminuria at baseline, but data regarding the effects on kidney failure or cardiovascular outcomes are limited. Microalbuminuria is much more common than frank proteinuria or albuminuria in patients with diabetes, but it is also associated with an increased risk of kidney and cardiovascular events. Several trials have shown a benefit of ACE-Is or ARBs over placebo in patients with microalbumi- nuria, irrespective of pre-treatment BP (See Supplementary All of these trials studied the effects of treatment on surrogate outcomes, most commonly the transition to overt proteinuria; none demonstrate conclu- sively that these improvements are associated with a reduction in hard end points in this population, although this may be the result of low event rates, inadequate statistical power, and short follow-up times. The Work Group believes that ACE-Is and ARBs should be the preferred classes of BP-lowering agent used in patients with diabetes and microalbuminuria, although the relatively weak available evidence is reflected in the poor grade assigned to this guideline statement (2D). We have not made statements about prevention of microalbuminuria as this topic will be addressed in the forthcoming KDOQI Diabetes guideline update.268 4.4: We recommend that an ARB or ACE-I be used in adults with diabetes and CKD ND with urine albumin excretion 4300mg per 24 hours (or equivalent*). (1B) *Approximate equivalents for albumin excretion rate per 24 hours expressed as protein excretion rate per 24 hours, albumin/creatinine ratio, protein/creatinine ratio, and protein reagent strip results are given in Table 1, Chapter 1. 