Conservative treatment to slow deterioration of renal function: evidence-based recommendations.

Despite current specific therapy, progressive deterioration of renal function in patients with primary glomerulonephritis occurs. Nonspecific renoprotective interventions that have been studied include blood pressure control, antihypertensive medications, and protein-restricted diets. To prepare this article, a MEDLINE search was conducted, followed by secondary and tertiary searches. Research papers were assessed for level of evidence, and graded recommendations were formulated. Protein-restricted diets (to 0.4 to 0.6 g/kg/day) are not recommended for all patients with reduced renal function (grade A). Very low-protein diets of 0.4 g/kg/day should be considered for patients with severe renal dysfunction (serum creatinine of more than 350 micromol/liter; grade A). However, there are concerns about recommending these diets for all patients because of the potential for long-term negative outcomes such as nutritional deficiencies. Target blood pressure for persons with proteinuria of more than 1 g/day should be less than 125/75 mm Hg [mean arterial pressure (MAP) < 92 mm Hg; grade C]. For persons with proteinuria of less than 1 g/day, the target blood pressure should be approximately MAP 98 mm Hg (less than 130/80; grade C). Angiotensin-converting enzyme inhibitor (ACEI) therapy is recommended in preference to placebo, conventional, or beta-blocker therapy for renoprotection (grade A). ACEI therapy cannot be recommended above calcium channel blockers in patients with nondiabetic renal disease (grade A).