Reducing excessive salt may improve urinary symptoms in patients with overactive bladder (OAB) and may be a reasonable behavioral treatment option, according to investigators.
In a study, 98 patients with OAB symptoms for at least 3 months and who also consumed excess salt, defined as 8 g/d for men or 7 g/d for women or more, were instructed to reduce their dietary intake of salt. Over 12 weeks, daily salt intake significantly decreased from 10.4 to 7.7 g/d and estimated 24-hour urinary sodium excretion dropped from 176.7 to 132.4 mEq/d in 71 patients. The remaining 27 patients did not successfully reduce dietary salt. Their salt intake increased significantly from 9.6 to 11.5 g/d and their sodium excretion rose from 164.3 to 196.4 mEq/d.
Only the salt restricted group had significant improvements in OAB symptom score (OABSS), Yasuyoshi Miyata, MD, PhD, of Nagasaki University Graduate School of Biomedical Sciences in Sakamoto, Nagasaki, Japan, and colleagues reported in Scientific Reports. In the salt restricted group, daytime frequency decreased from 1.2 to 0.6 episodes, nocturia from 2.1 to 1.4 episodes, urgency from 2.3 to 2.0 episodes, and urge incontinence from 1.3 to 1.1 episodes, Total OABSS score declined from 6.9 to 5.1. Frequency volume charts also revealed a significant 12.6 mL increase in voided volumes. After 12 weeks, 17 of the 71 (23.9%) patients in the salt restricted group no longer met OAB diagnostic criteria.
“Thus, salt intake reduction improved urinary symptoms in patients with OAB and may be a therapeutic option for OAB in patients with excessive daily salt intakes,” the investigators stated. They nonetheless acknowledged that a single behavioral therapeutic intervention is usually not sufficient for treating OAB.
Approximately two-thirds of the cohort were taking an OAB medication at baseline but experienced poor or no response over 3 months. They continued to take their OAB medication during the 12-week study.
Patients taking concomitant medications that could affect sodium excretion, such as diuretics or antidiuretic hormone, and patients with end-stage kidney disease were excluded from the study.
The small sample size was a study limitation. In addition, the investigators were unable to assess the effect of salt limitation on potential contributors to OAB, such as blood pressure, body mass index, oxidative stress, and neurotransmitters.
Matsuo T, Miyata Y, Otsubo A, et al. Efficacy of salt reduction for managing overactive bladder symptoms: a prospective study in patients with excessive daily salt intake. Sci Rep. 2021 Feb 18;11(1):4046. doi:10.1038/s41598-021-83725-9