Effect of salt intake reduction on nocturia in patients with excessive salt intake

To assess the efficacy of salt reduction for improving nocturia in patients with high salt intake.

Changes in lower urinary symptoms and frequency volume chart by salt intake (men: 8 g/day; women: ≥7 g/day) were analyzed in this prospective study. Patients were instructed to use a brochure for salt intake restriction via interview once every four weeks. The daily salt intake was estimated by using spot urine samples.

Two-hundred twenty-three (69.5%) patients were successful in reducing their daily salt intake (S group), whereas 98 (30.5%) patients failed to reduce their salt intake (F group). In the S group, nocturia improved from 2.3 ± 0.9 to 1.4 ± 1.0, and nocturnal polyuria index (NPi) improved from 30.2 ± 7.5 to 27.7 ± 7.3% (P < 0.001). In the Core Lower Urinary Tract Symptom Score (CLSS) of the S group, Q3 (urgency) improved from 1.0 ± 1.0 to 0.9 ± 1.0 (P = 0.001); Q1 (diurnal frequency) (P < 0.001), and Q2 (nocturia) also improved (P < 0.001). Moreover, the quality of life parameter improved significantly (P < 0.001). The patients in the F group did not have improvements in any symptom during the study period.

Patients with nocturia who also have high salt intake should be advised to reduce their salt intake, as a lifestyle modification. Our results support the importance of randomized clinical trials with larger populations and the appropriate inclusion/exclusion criteria to conclude the clinical usefulness of salt reduction in this patient cohort.