Randomized controlled crossover study of the effect on proteinuria and blood pressure of adding an angiotensin II receptor antagonist to an angiotensin converting enzyme inhibitor in normotensive patients with chronic renal disease and proteinuria

Background. Proteinuria and hypertension have independent deleterious effects on the progression of chronic renal disease. The objectives of this study were to determine whether the addition of Candesartan, an angiotensin II receptor antagonist, would reduce proteinuria and blood pressure in normotensive patients with chronic renal disease already receiving an angiotensin converting enzyme inhibitor (ACEI). Methods. This was an open randomized controlled crossover study conducted in a private consultant practice in Melbourne. Sixty patients, aged 23-75, who had chronic renal disease and stable proteinuria over 0.5 g in 24 h and were receiving an ACEI, were enrolled in the study. The patients were randomized to have 8 mg of Candesartan added in the first or second of two 12-week study periods. The primary end point was urine protein excretion, which was measured every 2 weeks for the 24-week period. Secondary end points included systolic and diastolic blood pressure, serum creatinine, urea and potassium levels. Candesartan was added against a background of standard care, which included other blood pressure lowering therapy. Results. Lower urine protein excretion 2.4 vs 2.0 g in 24 h (P<0.04, difference 0.45, CI 0.01, 0.9) and lower levels of systolic blood pressure 134 vs 128 mmHg (P<0.001, difference 6.4, CI 3.2, 9.6) and diastolic blood pressure 82 vs 80 mmHg (P<0.008, difference 2.7, CI 0.7, 4.6) were observed when Candesartan, 8 mg, was added to a regimen, which included an ACEI. No rise in serum creatinine occurred but there was a significant rise in urea, during the Candesartan arm of the study, from 12.3 to 13.8 mmol/l (P<0.001). The addition of 8 mg of Candesartan in normotensive patients with chronic renal disease receiving ACEI appeared safe and was not accompanied by adverse effects apart from postural hypotension in three patients and a serum potassium level of 6.3 mmol/l in one. Conclusions. In a private consulting practice setting, the addition of 8 mg of Candesartan in normotensive patients with chronic renal disease and proteinuria receiving an ACEI reduced proteinuria and blood pressure. The combination of Candesartan and ACEI appeared safe in this setting and may offer additional protection in preventing progression in chronic renal disease. Although the reduction of proteinuria was small (0.45 g/24 h) this reflected in part a lack of response in diabetic nephropathy and in part a marked rise in proteinuria after ceasing Candesartan in patients who did not complete the Candesartan arm of the study.