The Effects of Adding Spironolactone to ACEI or ARB on Proteinuria in Type 2 Diabetes

Objectives: Interruption of rennin-angiotensin-aldosterone system has become a leading therapeutic strategy in the treatment of diabetic nephropathy; however, ACEIs and ARBs do not uniformly suppress the rennin-angiotensin-aldosterone system. Plasma aldosterone levels are elevated in a group of patients despite therapy and this phenomenon known as aldosterone escape or aldosterone break through. Materials and Methods: Forty-two type 2 diabetic patients with overt proteinuria were randomized into two groups and according to double-blind case-control study, one group was treated with spironolactone and others were treated with placebo for 4 months. Twenty-four hours urine protein, glomerular filtration rate (GFR) and blood pressure were measured at baseline and after 4 months of treatment. Serum potassium was checked at baseline and one month of treatment. Results: Urine protein decreased in case group by 26.5% at the end of 4 months, but increased in control group by 17.9% (P=0.003). GFR did not have any significant change in case group (P < 0.354), but decreased in case group significantly (P < 0.001). Conclusion: Our study showed that spironolactone 12.5 mg/day is safe (without hyperkalemia and gynecomastia) and effective to decrease proteinuria in diabetic patient with CKD1-2.