Increased fluid intake to prevent urinary tract infections: systematic review and meta-analysis

BACKGROUND: Approximately 15% of community-prescribed antibiotics are used in treating urinary tract infections (UTIs). Increase in antibiotic resistance necessitates considering alternatives.

AIM: To assess the impact of increased fluid intake in individuals at risk for UTIs, for impact on UTI recurrence (primary outcome), antimicrobial use, and UTI symptoms (secondary outcomes).

DESIGN AND SETTING: A systematic review.

METHOD: The authors searched PubMed, Cochrane CENTRAL, EMBASE, two trial registries, and conducted forward and backward citation searches of included studies in January 2019. Randomised controlled trials of individuals at risk for UTIs were included; comparisons with antimicrobials were excluded. Different time-points (≤6 months and 12 months) were compared for the primary outcome. Risk of bias was assessed using Cochrane Risk of Bias tool. Meta-analyses were undertaken where ≥3 studies reported the same outcome.

RESULTS: Eight studies were included; seven were meta-analysed. There was a statistically non-significant reduction in the number of patients with any UTI recurrence in the increased fluid intake group compared with control after 12 months (odds ratio [OR] 0.39, 95% confidence interval [CI] = 0.15 to 1.03, P = 0.06); reduction was significant at ≤6 months (OR 0.13, 95% CI = 0.07 to 0.25, P<0.001). Excluding studies with low volume of fluid (<200 ml) significantly favoured increased fluid intake (OR 0.25, 95% CI = 0.11 to 0.59, P = 0.001). Increased fluid intake reduced the overall rate of all recurrent UTIs (rate ratio [RR] 0.46, 95% CI = 0.40 to 0.54, P<0.001); there was no difference in antimicrobial use (OR 0.52, 95% CI = 0.25 to 1.07, P = 0.08). Paucity of data precluded meta-analysing symptoms.

CONCLUSION: Given the minimal potential for harm, patients with recurrent UTIs could be advised to drink more fluids to reduce recurrent UTIs. Further research is warranted to establish the optimal volume and type of increased fluid.