[Antihypertensive therapy and renoprotection: do we really need to block the renin-angiotension system?]

Area of Science:

• Nephrology
• Cardiology
• Pharmacology

Background:

• Recent studies have questioned the specific renoprotective effects of ACE-inhibitors (ACE-i) and angiotensin receptor blockers (ARBs) beyond their blood pressure-lowering capabilities.
• The ALLHAT study indicated no superiority of lisinopril or amlodipine over chlorthalidone in preventing end-stage renal disease (ESRD) or significant GFR decline, even in patients with reduced GFR.
• Concerns exist regarding the ALLHAT study's patient selection (low renal risk) and medication adherence, as well as the heterogeneity and lack of individual patient data in meta-analyses like Casas et al.

Purpose of the Study:

• To evaluate the current evidence regarding the renoprotective effects of ACE-inhibitors (ACE-i) and angiotensin receptor blockers (ARBs).
• To determine if ACE-i and ARBs offer specific kidney protection independent of their blood pressure-lowering effects.
• To assess the validity of current guidelines recommending ACE-i/ARBs for renoprotection in kidney disease.

Main Methods:

• Review and analysis of existing studies, including the ALLHAT trial and meta-analyses such as Casas et al.
• Examination of findings from the Benedict Study concerning ACE-i therapy in hypertensive, type 2 diabetic patients.
• Synthesis of evidence to address the renoprotective efficacy of ACE-i and ARBs in both diabetic and non-diabetic kidney disease.

Main Results:

• The ALLHAT study showed no significant difference in renal outcomes between chlorthalidone, amlodipine, and lisinopril.
• Casas et al. concluded that ACE-i and ARBs may not be more renoprotective than other regimens, especially in diabetic nephropathy, with uncertain blood pressure-independent effects in non-diabetic kidney disease.
• The Benedict Study indicated that both blood pressure reduction and ACE-i therapy independently prevent microalbuminuria in hypertensive, normoalbuminuric type 2 diabetic patients, with ACE-i being more effective with poor BP control.

Conclusions:

• Despite conflicting study results and methodological concerns, the recommendation to use ACE-inhibitors (ACE-i) and/or angiotensin receptor blockers (ARBs) as first-line antihypertensive drugs for renoprotection in patients with diabetic and non-diabetic kidney disease remains valid.
• Blood pressure reduction and ACE-i therapy show independent renoprotective potential, particularly in patients with type 2 diabetes.
• Further research may be needed to fully elucidate the specific, blood pressure-independent renoprotective mechanisms of ACE-i and ARBs.