2241. Methenamine for the Prevention of Recurrent UTIs: A Desirability of Outcome Ranking (DOOR) analysis for the Alternative to Prophylactic Antibiotics for the Treatment of Recurrent Urinary Tract Infections in Women (ALTAR) Trial

Abstract

Abstract Background The Alternative to Prophylactic Antibiotics for the Treatment of Recurrent Urinary Tract Infections in Women (ALTAR) trial demonstrated that twice daily methenamine hippurate was non-inferior to daily low dose antibiotics for the prevention of recurrent UTIs. Non-inferiority trials are frequently misrepresented or misinterpreted by patients and clinicians, and often do not address which treatment approach is preferred. The Desirability of Outcome Ranking (DOOR) and Response Adjusted for Duration of Antibiotic Risk (RADAR) superiority methodology has been used as a secondary outcome in selected non-inferiority studies to incorporate antibiotic exposure and clinical outcomes. We applied DOOR/RADAR methodology to the ALTAR trial to evaluate the clinical superiority of methenamine hippurate as compared to antibiotic prophylaxis for the prevention of recurrent UTIs. Methods The first step in the DOOR/RADAR analysis was to generate categories to rank clinical outcomes. Using the data supplement of the ALTAR trial, categories were created by comparing the number of UTIs observed during the study period for the antibiotic versus methenamine groups. Participants were assigned a ranking using both clinical outcome and antibiotic use, with the principle that less antibiotic use is preferred as long as the same clinical outcome is achieved. The Mann-Whitney U test was then used to compare outcomes between these groups. Results The study included 205 patients, with 103 receiving methenamine and 102 receiving low dose antibiotics. The methenamine and antibiotic prophylaxis groups were divided into categories based on number of UTIs observed during study period (Table 1), with the density of the DOOR/RADAR outcomes displayed in Figure 1. Using the Mann-Whitney U test, the probability of a better DOOR score (i.e. more desirable outcome) for a randomly selected patient from the methenamine group compared to the antibiotic group was 58% (p-value 0.045). Number of UTIs by Treatment Group Table 1.Number of UTIs observed during study period between groups receiving methenamine as compared to antibiotic prophylaxis. The most desirable outcome (*) and the least desirable outcome (**) are designated above. Figure 1. The density of DOOR/RADAR outcomes of methenamine as compared to antibiotic prophylaxis group. Conclusion Applying the DOOR/RADAR analysis to the data from the ALTAR trial provides evidence to suggest that there is a higher probability for desirable outcomes in women who receive methenamine hippurate as compared to prophylactic antibiotics for the prevention of UTIs. Disclosures All Authors: No reported disclosures.