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Increasing fluid intake reduces recurrent cystitis in some women

Urging women who drink little to drink more could cut use of antimicrobials, and help fight resistance

Louise Prime

Tuesday, 02 October 2018

Increasing daily water intake reduces the incidence of recurrent cystitis in premenopausal women experiencing recurrent cystitis who drink low volumes of total fluid daily, a US-led randomised trial has shown, although it does not show whether or not increased water intake is beneficial in women who are at lower risk for recurrent cystitis or who regularly drink higher quantities of fluid. The authors of the study*, published in JAMA Internal Medicine, said that encouraging women with recurrent cystitis who drink little to increase their fluid intake could result in lower use of antimicrobials to treat recurrent cystitis, and could be beneficial in terms of antimicrobial resistance.

The trial took place at a clinical research centre in Sofia, Bulgaria from 2013 to 2016, among 140 healthy women (mean age 35.7 years) with recurrent cystitis (i.e. at least three episodes in the past year; mean 3.3) who drank less than 1.5 litres of fluid daily. Participants were randomised to either drink, in addition to their usual fluid intake, 1.5 litres of water daily (water group), or no additional fluids (control group), for 12 months.

Researchers made assessments of daily fluid intake, urinary hydration, and cystitis symptoms at baseline, six- and 12-month visits, and monthly telephone calls. Their primary outcome measure was the frequency of recurrent cystitis over 12 months, but they also compared the number of antimicrobial regimens used, mean time interval between cystitis episodes, and 24-hour urinary hydration measurements between the water and control groups.

They reported that overall, there were 327 cystitis episodes, 111 in the water group and 216 in the control group. The mean number of cystitis episodes per woman was 1.7 in the water group, compared with 3.2 in the control group; the mean number of antimicrobial regimens used to treat cystitis episodes was 1.9 and 3.6 respectively; and the mean time interval between cystitis episodes was 142.8 days and 84.4 days, respectively. Between baseline and 12 months, participants in the water group, compared with those in the control group, had increased mean urine volume (1.4 litres vs 0.1 litres) and voids (2.4 litres vs −0.1 litres) as well as decreased urine osmolality (−402.8mOsm/kg vs −24.0mOsm/kg).

The study authors noted that they did not look at what increment in daily water intake is sufficient for reducing risk of urinary tract infection and added: “We do not know whether increased water intake is beneficial in women who are at lower risk for recurrent cystitis or who regularly drink higher quantities of fluid than women in this study.”

They concluded: “It seems appropriate for clinicians who counsel healthy women with recurrent cystitis to routinely ask about daily fluid intake and to recommend increased intake of water, especially in those who drink no more than 1.5 litres of fluids daily, as a safe and inexpensive alternative to strategies that employ antimicrobials. The resulting reduction in antimicrobial use for treatment and prevention of cystitis in women is likely to have an important beneficial effect on antimicrobial resistance.”

*Hooton TM, Vecchio M, Iroz A, et al. Effect of increased daily water intake in premenopausal women with recurrent urinary tract infections: a randomized clinical trial. JAMA Intern Med. Published online October 01, 2018. doi:10.1001/jamainternmed.2018.4204

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