Nocturnal Polyuria and Natriuresis in Male Patients with Nocturia and Lower Urinary Tract Symptoms

PURPOSE: We investigated the circadian variation in urine output, plasma angiotensin II, aldosterone, atrial natriuretic peptide, arginine vasopressin and blood pressure. MATERIALS AND METHODS: We studied 17 elderly men with nocturia and lower urinary tract symptoms, and 10 age matched controls without nocturia. RESULTS: Of the 17 patients studied 11 had a lack of diurnal variation in urine output and increased nocturnal urine production associated with increased nocturnal sodium excretion, and 6 had a diurnal variation in urine output comparable to controls. CONCLUSIONS: Nocturia in a large proportion of elderly men with lower urinary tract symptoms is caused by nocturnal polyuria and natriuresis.