The multicentre, randomised, non-inferiority ALTAR trial (ISRCTN70219762) included 240 women with recurrent UTIs to compare the effectiveness of antibiotic prophylaxis (n=120) with that of methenamine hippurate (n=120). The primary outcome was the incidence of self-reported symptomatic antibiotic-treated UTIs during the 12-month treatment period, with a non-inferiority margin of 1 UTI episode per year.
Methenamine hippurate demonstrated non-inferiority to antibiotic prophylaxis, with incidence rates of 1.38 (95% CI 1.05–1.72) and 0.89 (95% CI 0.65–1.12), respectively. Prof. Christopher Harding (Newcastle University, UK) added that only 52% of the antibiotic-treated UTIs were confirmed by a positive culture, indicating that relying on microbiological cultures only would result in missing almost half of the UTIs. Next, patients in the antibiotic prophylaxis arm displayed a trend towards a higher resistance to at least one antibiotic in E. coli during the 12-month treatment period compared with the patients in the non-antibiotic treatment arm (P=0.052).
Prof. Harding concluded that the results of the ALTAR trial show that methenamine hippurate is an effective alternative to antibiotic preventive treatments in women with recurrent UTIs and that this agent should be considered a novel first-line standard of care.
1. Harding C, et al. Alternative to prophylactic antibiotics for the treatment of recurrent urinary tract infections in women: multicentre, open label, randomised, non-inferiority trial. Game-changing session 4, EAU 2022, 01–04 July.