Patients with renal disease often experience a reduced quality of life with increased morbidity and mortality. The ability of angiotensin-converting enzyme (ACE) inhibitors to slow the progression of renal disease in patients with type 1 and type 2 diabetes is becoming clear. Their efficacy in patients with nondiabetic renal disease is less clear. Jafar and associates pooled data from 11 randomized, controlled studies and compared the effects of antihypertensive regimens with and without ACE inhibitors on renal disease.
All 1,860 study participants had either hypertension or diminished renal function. The ACE inhibitor used varied among studies. All patients received regular blood pressure measurements and laboratory testing. The primary outcomes were end-stage renal disease (ESRD) and a twofold increase in serum creatinine concentration.
The patients treated with ACE inhibitors had a lower rate of ESRD and doubling of the serum creatinine level. The beneficial effect of ACE inhibitors was greater in patients with higher urinary protein excretion. Factors that were independently associated with increased risk of ESRD included younger age, female gender, higher serum creatinine concentration, higher systolic blood pressure and higher urinary protein concentration.
The authors conclude that ACE inhibitors should be the initial antihypertensive treatment in patients with nondiabetic renal disease, especially if proteinuria is greater than 0.5 g per day. This ability to slow the progression of renal disease appears to be independent of successfully lowering the blood pressure or decreasing renal protein excretion.
In an accompanying editorial, Schrier and Estacio discuss the difficulties of using a meta-analysis to make definitive clinical recommendations. Variations in blood pressure control, antihypertensive treatment regimens, and urinary protein excretion in the various trials make data aggregation difficult. Further studies are needed to investigate the value of ACE inhibitor therapy in patients with lower levels of urinary protein excretion. The authors assert that although the conclusion that ACE inhibitors have value in the management of nondiabetic renal disease may be correct, further long-term, randomized, controlled studies are needed.