[The antiproteinuric effect of the blockage of the renin-angiotensin-aldosterone system (RAAS) in obese patients. Which treatment option is the most effective? ].

BACKGROUND: Obesity increases the risk of proteinuria and chronic renal insufficiency and hastens the progression of renal diseases. Increased activity of renin-angiotensin-aldosterone system and elevated levels of aldosterone are common in obese patients. No studies have compared the efficacy of the currently available antiproteinuric strategies (ACE inhibitors -ACEI-, angiotensin receptor blockers -ARB-, aldosterone antagonists) in obese patients with proteinuric renal diseases.

METHODS: Single centre, prospective, randomized study. Twelve obese patients (body mass index > 30 Kg/m2) with proteinuria > 0.5 g/24 h were selected from our outpatient renal clinic. Patients were consecutively treated during 6 weeks with an ACEI (lisinopril 20 mg/day), combined therapy ACEI+ARB (lisinopril 10 mg/day + candesartan 16 mg/day) and eplerenone (25 mg/day) in random order. A drug washout period of 6 weeks was established between the different treatment periods. The primary outcome point was the change in 24-h proteinuria at the end of each treatment period and the number of patients showing a proteinuria reduction greater than 25% of baseline.

RESULTS: The reduction in proteinuria induced by lisinopril (11.3+/-34.8%) was not statistically significant with respect to baseline, whereas that of lisinopril plus candesartan (26.9+/-30.6%) and eplerenone (28.4+/-31.6%) showed a statistically significant difference both with respect to baseline values and to lisinopril group. The number of patients who showed a greater than 25% proteinuria reduction was significantly higher with eplerenone (67%) and lisinopril+candesartan (67%) than with lisinopril (25%).

CONCLUSIONS: Monotherapy with an aldosterone antagonist and combination therapy with ACEI+ARB were more effective than ACEI monotherapy to reduce proteinuria in obese patients with proteinuric renal diseases.