Fisher H, et al. - In adult users of clean intermittent self-catheterisation (CISC), researchers assessed the benefits, harms, and cost-effectiveness of continuous low-dose antibiotic prophylaxis for prevention of recurrent urinary tract infections (UTIs). Good tolerability of continuous antibiotic prophylaxis as well as its efficacy in reducing UTI frequency in CISC users with recurrent UTIs was demonstrated by the findings. However, surveillance for increased resistance of urinary bacteria, which represents a concern, is required if prophylaxis is started.

Methods

• This randomised, open-label, superiority trial included community-dwelling (as opposed to hospital inpatient) users of CISC with recurrent UTIs from 51 UK National Health Service organisations
• Using an internet-based system with permuted blocks of variable length, participants were randomized (1:1) to receive either antibiotic prophylaxis once daily (prophylaxis group) or no prophylaxis (control group) for 12 months.
• Participants were aware of their treatment group, however, trial and laboratory staff who assessed outcomes were masked to allocation.
• The incidence of symptomatic, antibiotic-treated UTIs over 12 months was assessed as primary outcome.
• In the analysis of the primary outcome, participants who completed at least 6 months of follow-up were included, and were assumed to provide a reliable estimate of UTI incidence.
• Secondary outcome included change in antimicrobial resistance of urinary and faecal bacteria.

Results

• Screening for eligibility was carried out in 1,743 adult users of CISC, between Nov 25, 2013, and Jan 29, 2016.
• Of those, 404 (23%) participants were enrolled between Nov 26, 2013, and Jan 31, 2016; of these, 203 (50%) received prophylaxis and 201 (50%) did not.
• 1339 participants were excluded before randomisation.
• A total of 181 (89%) adults allocated to the prophylaxis group and 180 (90%) adults in the no prophylaxis (control) group were included in the primary analysis.
• Twenty-two participants in the prophylaxis group and 21 participants in the control group were missing follow-up data before 6 months and therefore, were not included in the primary analysis.
• In the prophylaxis group and in the control group, the incidence of symptomatic antibiotic-treated UTIs over 12 months was 1·3 cases per person-year (95% CI 1·1–1·6) and 2·6 (2·3–2·9), respectively, giving an incidence rate ratio of 0·52 (0·44–0·61; p<0·0001), indicating a 48% reduction in UTI frequency after treatment with prophylaxis.
• Good tolerability of prophylaxis was reported: the prophylaxis group had 22 minor adverse events related to antibiotic prophylaxis during the study, predominantly gastrointestinal disturbance (six participants), skin rash (six participants), and candidal infection (four participants).
• However, at 9–12 months of trial participation, urinary isolates from the prophylaxis group vs those from the control group showed more frequent resistance against the antibiotics used for UTI treatment {nitrofurantoin 12 [24%] of 51 participants from the prophylaxis group vs six [9%] of 64 participants from the control group with at least one isolate; p=0·038), trimethoprim (34 [67%] of 51 vs 21 [33%] of 64; p=0·0003), and co-trimoxazole (26 [53%] of 49 vs 15 [24%] of 62; p=0·002)}.