Can Drinking More Water Prevent Recurrent Urinary Tract Infections?

BACKGROUND AND PURPOSE: 

  • Research suggests that 15% of all antimicrobial use is for UTI treatment 
    • Risk of increased antimicrobial resistance 
    • May not help prevent recurrence  
  • Hooton et al. (JAMA Internal Medicine) examined the efficacy of increased daily water intake on the frequency of recurrent cystitis in premenopausal women

METHODS: 

  • Randomized, open-lebel, controlled trial (RCT) 
  • Participants 
    • Healthy women with recurrent cystitis (≥3 episodes in past year with at least one culture confirmed) 
    • ≥18 years of age  
    • Self-reported drinking of <1.5 L of fluid daily 
  • Randomized to either  
    • Water group: 1.5 L of water daily in addition to usual fluids 
    • Control group: No additional fluids 
  • Water group intervention 
    • 500-mL bottles of water (Evian) consumed daily 
    • Suggested to start a bottle prior to every meal and finish it prior to the next meal  
  • Primary outcome: Frequency of cystitis recurrence over 12 months 
  • Secondary outcomes  
    • Number of antimicrobial regimens used | Mean time interval between cystitis episodes | 24-hour urinary hydration measurements 
  • Sample size 
    • 42 per group to achieve 80% power (type I error rate of 5%) 
    • Assuming a 40% drop out rate, 70 participants per group would need to be randomized

RESULTS: 

  • 64 women in the water group | 66 women in the control group  
    • Mean (SD) age: 35.7 (8.4) years 
  • During the 12-month study period, the mean (SD) number of cystitis episodes was 
    • 1.7 (95% CI, 1.5-1.8) in the water group  
    • 3.2 (95% CI, 3.0-3.4) in the control group 
    • Difference in means of 1.5 (95% CI, 1.2-1.8; P < .001) 
  • Overall, there were 327 cystitis episodes 
    • 111 in the water group 
    • 216 in the control group 
  • The mean number of antimicrobial regimens used to treat cystitis episodes was 
    • 1.9 (95% CI, 1.7-2.2) in the water group 
    • 3.6 (95% CI, 3.3-4.0) in the control group 
    • A difference in means of 1.7 (95% CI, 1.3-2.1; P < .001) 
  • The mean time interval between cystitis episodes was 
    • 142.8 (95% CI, 127.4-160.1) days in the water group 
    • 84.4 (95% CI, 75.4-94.5) days in the control group 
    • A difference in means of 58.4 (95% CI, 39.4-77.4; P < .001) 
  • Between baseline and 12 months, participants in the water group, compared with those in the control group, had 
    • Increased mean urine volume: 1.4 vs 0.1L; (P < .001) 
    • Increased voids: 2.4 vs −0.1 (P < .001)  
    • Decreased urine osmolality: −402.8 vs −24.0 mOsm/kg (P < .001)

CONCLUSION: 

  • Drinking water decreased risk of UTI in premenopausal women at risk for recurrence  
  • Dose response not done in this study so authors cannot know for certain how much daily additional water can lead to UTI reduction  
  • The authors state that based on these results 

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 L of fluids daily 

Learn More – Primary Sources: 

Effect of Increased Daily Water Intake in Premenopausal Women With Recurrent Urinary Tract Infections – A Randomized Clinical Trial