Patients with cystitis should be objectively educated on pros and cons of increasing water intake.
Background: Increased water intake is commonly recommended to prevent recurrent cystitis in premenopausal women, but the overall conclusive evidence and research is weak.
Objective: To determine the impact of increasing daily water intake on recurrent cystitis frequency.
Design: Randomized, open-labeled, controlled, 12-month clinical conducted at 1 research center in Sofia, Bulgaria, but also overseen by U.S. researchers and supported by Danone Research.
Methods: 140 healthy women with ≥3 episodes of recurrent cystitis in the past year consuming <1.5 L (approximately 51 ounces) fluid daily were included. Baseline, 6-month, and 12-month visits occurred along with monthly phone calls. Participants were assigned to drink their normal fluid intake in addition to 1.5 L of water or no extra fluids (control group) for 12 months. Mean age was 35 years.
Results: Mean number of episodes was 1.7 for water and 3.2 for control (P <0.001). Mean number of antibiotic treatments used to treat cystitis was 1.9 and 3.6 (P <0.001). Mean time between episodes was 142.8 and 84.4 days (P <0.001). Participants in the water group versus control had increased mean urine volume (P <0.04) and voids and reduced urine osmolality (both P <0.001).
Conclusions: Increased water consumption is an effective antibiotic-reducing method to prevent recurrent cystitis in high-risk premenopausal women who usually drink low levels of fluids daily.
Reviewer’s Comments: The occasional Internet advice to consume 8 glasses of water per day to improve your health has minimal to no evidence, but preliminary research is beginning to support something similar to this practice in urology to prevent kidney stones and now perhaps recurrent cystitis in premenopausal women who usually consume low levels of fluids (average of 0.5 L or 17 ounces/day). This is an unusually low amount (basically 2 cups of water per day) that was being consumed at baseline. What was missed is that 20% to 25% on average of fluid or water intake in humans actually comes from food sources, and this was not taken into account or addressed, which is surprising. In addition, the study occurred in Bulgaria at a clinical research center and not in the United States despite the slight indirect implication, and a commercial water source funded the study. Side effects were similar between the groups. Regardless, discussing fluid intake with patients is a logical, practical, and cost-effective option for patients that fit the criteria of this study.(Reviewer–Mark Moyad, MD, MPH).
Article Reviewed: Effect of Increased Daily Water Intake in Premenopausal Women With Recurrent Urinary Tract Infections: A Randomized Clinical Trial. Hooton TM, Vecchio M, et al: JAMA Intern Med; 2018;178 (November 1): 1509-1515.