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

AIMS: To assess the efficacy of salt reduction for improving nocturia in patients with high salt intake. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Daily salt intake is an independent risk factor for pollakiuria and nocturia.

OBJECTIVE: To clarify the relationships between daily salt intake and lower urinary tract symptoms. METHODS: A cross-sectional clinical study was carried out with 728 patients. Spot urine samples were collected to evaluate estimated daily salt intake. The patients were divided into two groups based on mean salt intake (9.2 g/day). Their urinary condition was evaluated using the Core Lower Urinary Tract Symptoms score and 3-day frequency volume charts. The influence of salt intake on lower urinary tract symptoms was investigated using multivariate logistic regression analysis. RESULTS: Daytime frequency (Q1) and nocturia (Q2) in the high salt intake group (H-salt group) were higher compared with those in the low salt intake group (L-salt group); P < 0.001). The quality of life scores and nocturnal polyuria index in the H-salt group were worse than those in the L-salt group (P < 0.001). Multivariate analyses showed daily salt intake is an independent worsening factor for high daytime frequency (odds ratio 2.32, 95% confidential interval 1.66-3.25, P < 0.001) and nocturia (odds ratio 3.05, 95% confidential interval 2.08-4.52, P < 0.001). Similarly, hypertension was identified as the independent variable for these symptoms. A limitation of the present study was that we recruited only patients with mild or no comorbidity. CONCLUSIONS: Excessive daily salt intake negatively affects pollakiuria and nocturia. The presence of hypertension can also represent a worsening factor for these symptoms. Although not shown by prospective study, the appropriate control of salt intake and blood pressure might be important for the treatment of pollakiuria and nocturia.

How should patients with an overactive bladder manipulate their fluid intake?

OBJECTIVE: To assess how the symptoms of overactive bladder (OAB) syndrome in adults are affected by decreasing or increasing fluid input, and the effect of fluid manipulation on quality of life. PATIENTS AND METHODS: Adults with symptoms of OAB were randomized in a two-group, prospective, cross-over trial following a 4-day screening period (to establish baseline values) using frequency/volume charts, if they had a mean of eight or more voids and one or more urgency and/or urgency incontinence episodes in 24-h. Patients were asked to either increase or decrease their fluid intake, from baseline, as follows: group 1, 4 days drinking 25% less than baseline, and 2 days normal, then 4 days at 50% less than baseline, and 2 days normal, then 4 days at 25% more than baseline, and 2 days normal, and then 4 days at 50% more than baseline. Group 2 did the reverse. The primary endpoint was the change in the frequency of unwanted events during a 24-h period. RESULTS: In all, 67 patients were contacted, 40 recruited and 24 were eligible. There was a significant reduction in frequency, urgency and nocturia when patients decreased their fluid input by 25%. Increasing fluid input by 25% and 50% resulted in a worsening of daytime frequency. Overall there was no statistically significant improvement in quality of life but there was some subjective improvement in urgency and nocturia, as measured by a validated instrument, in the group that decreased their fluid input by 25%; approximately 300 mL of daily fluid came from water-containing foods. CONCLUSIONS: Fluid manipulation is a cheap, noninvasive and easy way to help control the symptoms of OAB. Patients have difficulty in either decreasing or increasing their fluid input by 50%. Patients can now be told to expect a significant improvement in urgency, frequency and nocturia episodes if they reduce their fluid input by 25%.