Objectives: To obtain information about the effect of prolonged aldosterone excess on kidney function.
Methods: We determined kidney function changes defined by cystatin C-based estimations of glomerular filtration rate (CysC-GFR). Pretreatment proteinuria and intrarenal Doppler velocimetric indices in primary aldosteronism were examined and followed after adrenalectomy or spironolactone treatment.
Results: This prospective, multicenter study included 130 primary aldosteronism patients (56 men; age, 49.9 ± 13.4 years: 100 with adenoma and 30 with idiopathic hyperaldosteronism) and 73 essential hypertension patients (36 men; age, 51.4 ± 14.8 years) as controls. Patients with primary aldosteronism had higher CysC-GFR (P < 0.05) and heavier proteinuria (0.042) than those with essential hypertension. With primary aldosteronism, a higher aldosterone-renin ratio (odds ratio, OR = 7.85, P = 0.008) was independently related to pretreatment CysC-GFR. The factors related to pretreatment proteinuria included CysC-GFR (OR, -0.006, P = 0.001), plasma aldosterone concentration (OR, 0.004, P = 0.002), and duration of hypertension (OR, 0.016, P = 0.032). Duration of hypertension was also independently correlated with the pretreatment resistive index among primary aldosteronism patients (OR, 0.004, P = 0.035). CysC-GFR (all, P < 0.05), proteinuria (P < 0.001), and resistive index (P < 0.001) decreased 1 year after adrenalectomy but not with spironolactone treatment.
Conclusion: Our data suggest that prolonged hyperaldosteronism will cause relative kidney hyperfiltration and reversible intrarenal vascular structural changes, which disguise the consequent renal injury, including declining GFR and proteinuria. Adrenalectomy and spironolactone treatment exert different clinical impacts toward kidney damage even with a similar blood pressure-lowering effect.