Methods: We used the search terms “recurrent”, “UTI”, “prophylaxis”, “antibiotic”, and “RCT” among others. We screened MEDLINE, EMBASE, the Cochrane Library, clinicaltrials.gov and reference lists of retrieved articles. We considered any published RCT in adults where antibiotics were used as RUTI prophylaxis. From the selected articles we extracted data on RUTI episodes in both comparators (antibiotic vs. antibiotic or placebo). For statistical analyses, we used the random effects model and expressed the results as odds ratio (OR) with 95% confidence intervals (CI).
Results: We included 22 RCTs in this meta-analysis. Summarizing the 13 placebo-controlled (PC) studies, the odds ratio for developing UTI was 0.07 (95% CI 0.03-0.13); the corresponding overall risk reduction was 52% (NNT 2.3). After 2004, a single RCT, comparing fosfomycin to placebo, was conducted and revealed an absolute UTI risk reduction of 68% (NNT 1.5). The 8 RCTs that remained after excluding cinoxacin, an obsolete antibiotic, had a similar OR [0.06 (0.03-0.14)]. For PC studies, overall study quality was low and the funnel plot indicated potential publication bias. In the 8 head-to-head trials of different prophylactic antibiotics, nitrofurantoin was the single most common comparator [to norfloxacin (3 studies), cefaclor (2) or trimethoprim (3)]; there was no significant treatment difference [OR 1.10 (0.83-1.47)]. Four studies compared trimethoprim (± sulfamethoxazole) to other antibiotics [OR 0.86 (0.48-1.56) and 3 compared norfloxacin to others [OR 1.17 (0.59-2.33)]. One RCT compared continuous versus post-coital ciprofloxacin and found no difference either [OR 0.71 (0.11-4.38)].
Conclusion: Antibiotic prophylaxis for the prevention of recurrent UTI confers a 50% risk reduction (NNT=2). Head-to-head trials were mainly published for nitrofurantoin vs. comparators and show no significant difference in RUTI rates, making nitrofurantoin, norfloxacin and TMP/SMZ interchangeable options. Over the last decade, only very few RCTs have been added to the scientific literature.
A. Kuhn, None
J. Marschall, Astellar Switzerland: Scientific Advisor , Consulting fee