Recurrent Cystitis? Drink More Water Upping water intake lowered risk of urinary tract infection in randomized trial

October 11, 2017 8:41 AM | Ashley Monson (Administrator)
by Michael Smith, North American Correspondent, MedPage

October 06, 2017

Action Points

SAN DIEGO -- A few extra glasses of water a day could cut the risk of urinary tract infections for women plagued with recurrent episodes, a researcher said here.

In a randomized trial, drinking about three extra pints of water a day cut the risk of uncomplicated acute cystitis (AUC) by about half, according to Thomas Hooton, MD, of the University of Miami School of Medicine.

The extra water was also associated with fewer courses of antibiotics during the year-long study, Hooton told reporters here at the annual IDWeek meeting, sponsored jointly by the Infectious Diseases Society of American (IDSA), the Pediatric Infectious Diseases Society (PIDS), the Society for Healthcare Epidemiology of America (SHEA), and the HIV Medicine Association (HIVMA).

The finding is not really a surprise, Hooton said -- doctors have long been telling women to drink more water to prevent or help treat recurring AUC.

The idea makes sense, he said, because the conventional wisdom has been that disease-causing bacteria make their way from the vagina up the urethra to the bladder. Frequent flushing with urine can prevent the bacteria from sticking to bladder cells, growing, and causing disease.

But while that's a good story, he said, there had been no real study of the issue. "You always want to have confirmatory data," Hooton said. "It helps to be able to say there's a well-done study that looked at this question very carefully and showed the risk was pretty dramatically reduced."

To obtain that data, he and colleagues enrolled 140 premenopausal women whose self-reported fluid intake was low -- less than 1.5 liters of total fluid a day -- and who had had at least three episodes of AUC in the previous year.

They were randomly assigned 1:1 to increase their water intake by 1.5 L a day or to make no change in their habits.

The investigators had monthly telephone calls with all participants as well as regular clinic visits in which such things as urine volume and osmolality -- a measure of the concentration of the fluid -- were tested.

Women in the intervention group were given 500 mL bottles of water and urged to begin drinking one at the start of each meal and to finish it before the next meal, Hooton said.

Over the study period, the 70 women in the intervention group:

  • Increased their water intake significantly compared with the control group -- an increase of 1.15 L on average versus an average drop of 0.01 L
  • Raised their average total fluid intake by 1.65 L versus 0.03 L among the control group
  • Upped average urine volume and number of urine voids -- 1.40 L versus 0.04 L and 2.2 a day versus a decrease of 0.2, respectively
  • Saw a decrease in urine osmolality of 408 mOsm/kg versus 35 in controls

But the key finding, Hooton said, was that the average number of recurrent AUC episodes in the water group over the year was 1.6, compared with 3.1 among the control women. Those number yielded an odds ratio for AUC of 0.52, which was highly significant, he said.

As might be expected, the average number of antimicrobial regimens used to treat AUC was 1.8 in the water group and 3.5 in the control group, which was again significant. As well, he noted, the average number of days to first AUC after the start of the study and the mean number of days between episodes was longer for those in the water group.

The findings are important because many women suffer recurrent AUC and most are treated with antibiotics, commented Susan Bleasdale, MD, of the University of Illinois at Chicago, who moderated a media briefing on the trial.

The study, she told reporters, "may be a game-changer" in the way antibiotics are used.

The usual advice doctors give women to keep hydrated often comes when they are already in the throes of an infection -- advice often given along with a prescription for antibiotics. The point of the study, she said, is that increased water intake appears to prevent the infections in the first place -- and therefore the need for scripts.

While the study took place among premenopausal women at risk for recurrent AUC, Hooton said he sees no reason it would not apply to those past the menopause, as well as to women of all ages who suffer less frequent attacks. But he added that hasn't yet been demonstrated.

Hooton said he had no disclosures to make.

The study had support from Danone Research.

Bleasdale made no disclosures.

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