People performing clean intermittent self-catheterisation (CISC) often suffer from repeated urinary tract infections (UTI)s. Previous studies have shown that continuous once-daily, low dose antibiotic prophylaxis is effective in women with normal functioning bladders who suffer from repeated UTI. However, evidence regarding the effectiveness of this strategy is in CISC users is lacking. The aim of this randomised control trial was to assess the benefit and harms of antibiotic prophylaxis to prevent UTI among people performing CISC.

This parallel-group, open-label, superiority, patient-randomised trial recruited from the UK National Health Service organisations between 26/11/2013 and 31/01/2016. Adult CISC users were eligible to take part if they were predicted to continue using CISC for the next 12 months and had a history of repeated UTI. 

Participants were allocated 1:1 to either once-daily oral antibiotic prophylaxis (nitrofurantoin, trimethoprim or cefalexin) or no prophylaxis, for 12 months. Randomisation was performed centrally using an internet-based system with permuted blocks of variable length. Trial and laboratory staff assessing outcomes were masked to allocation.

The primary clinical outcome was frequency of symptomatic, antibiotic-treated UTI over 12 months. The primary modified intention to treat analysis included all participants who had completed at least 6 months follow up. Secondary outcome measures included frequency of microbiologically confirmed UTI, antimicrobial resistance, health status and participants’ attitudes to antibiotic use.

A total of 404 participants were randomised out of 1743 patients screened for eligibility. We included 361/404 (89%) participants in the primary modified intention to treat analysis: 181/203 (89%) in the prophylaxis group and 180/201 (90%) in the no prophylaxis group. 

The incidence rate (95% confidence interval) of symptomatic antibiotic-treated UTI over 12 months was 1.3 (1.1 – 1.6) in the prophylaxis group and 2.6 (2.3 – 2.9) in the no-prophylaxis group. This equates to an incidence rate ratio (IRR) of 0.52 (0.44 – 0.61); a 48% reduction in UTI frequency in the prophylaxis group. Use of prophylaxis was well-tolerated, with 19 participants in the prophylaxis group suffering adverse events relating to the use of prophylactic antibiotics predominantly gastro-intestinal disturbance, candida infection and skin rash. Development of antimicrobial resistance was seen more frequently in pathogens and commensals isolated from urine and Escherichia coli from perianal swabs in the prophylaxis group.

This randomised controlled trial used a pragmatic design within standard health-care settings to provide robust evidence of a substantial reduction in frequency of antibiotic treated symptomatic UTI for CISC users by taking a once-daily, low dose of one of the licensed agents (nitrofurantoin, trimethoprim or cefalexin) over a 12 month period. Prophylaxis was well-tolerated, with few participants suffering overt harm and the majority of users expressing a preference to continue with prophylaxis after the trial had ended. The increase in antimicrobial resistance of pathogens causing UTI to commonly used antibiotics may reduce the long-term efficacy of UTI treatment in individuals continuing to perform CISC and is also a major public health concern.

This large randomised trial demonstrates a clear benefit for antibiotic prophylaxis in terms of reducing frequency of UTI for people performing CISC. Antibiotic prophylaxis use appears tolerable for individuals over 12 months.  The emergence of resistant urinary pathogens is a major public health concern and may prejudice  management of recurrent UTI in the longer term.