Effect of spironolactone on diabetic nephropathy compared to the combination of spironolactone and losartan.

BACKGROUND: Diabetic nephropathy is the most important cause of end stage renal disease (ESRD). Aldosterone is involved in renal damage through induction of fibrosis, inflammation and necrosis in the kidney tissue. Previous studies have demonstrated that the combination of angiotensin receptor blocker (ARB) and spironolactone (an anti-aldosterone drug) are efficient for albuminuria reduction.

OBJECTIVES: This study was designed to evaluate the effect of spironolactone alone on diabetic nephropathy.

PATIENTS AND METHODS: In this double blind randomized clinical trial, 60 type II diabetic patients with microalbuminuria were enrolled. They were divided into two groups: case group (spironolactone 25 mg and placebo, 30 cases) and control (spironolactone 25 mg plus losartan 25 mg, 30 cases). The treatment success rate (more than 50% reduction in microalbuminuria) was compared between the two groups.

RESULTS: After three months, successful treatment was seen in 70% (95% CI: 52 - 83) and 83.3% (CI 95%: 66 - 93) of case and control groups, respectively (P = 0.4). Mean ± SD of serum potassium levels after three months in case and control groups were 4.56 ± 0.38 and 4.39 ± 0.34 mEq/L, respectively (P = 0.08). Mean ± SD of systolic blood pressures in case and control groups were 129.67 ± 9.4 and 130.97 ± 9.4 mmHg, respectively (P = 0.6). Mean ± SD of serum creatinine levels at the end of the study were 0.95 ± 0.15 in case and 0.90 ± 0.22 mg/dL in control group (P = 0.4).

CONCLUSIONS: Spironolactone alone is as effective as the combination of spironolactone and losartan on albuminuria reduction in type 2 diabetic patients and can be used alone as an effective drug for diabetic nephropathy.