A Trial of D-mannose for the Prophylaxis of Recurrent Urinary Tract Infections

Inclusion Criteria: * Female, post-menopausal, age ≥ 55 years old * Diagnosis of recurrent UTI, defined as ≥ 3 symptomatic culture-proven UTI episodes in 12 months or ≥ 2 in 6 months. * Currently free from a UTI determined based on absence of symptoms as determined by the UTI symptom assessment questionnaire79 and negative urine culture (\<103 colony forming units per ml of urine). * Able to attend all follow-up appointments for the study. * A negative upper and lower urinary tract evaluation, including pelvic examination for pelvic organ prolapse (less than stage 2), measurement of post-void residual (less than 50 ml), and imaging (renal ultrasound and standing voiding cystourethrogram) to exclude kidney stone, hydronephrosis, reflux, or urethral diverticulum. Exclusion Criteria: * Current use of D-mannose. Patients willing to stop taking D-mannose will be offered to join the trial after a 4-week wash-out period. * Complicated UTIs, including need for catheter drainage or intermittent catheterization, neurogenic bladder, bladder augmentation, or urinary diversion. * Ongoing supplement use (Box 1). Patients willing to stop taking the listed supplements will be offered to join the trial after a 4-week wash-out period. * Evidence of upper tract infection (pyelonephritis), including temperature higher than 38°C, flank/lumbar pain or tenderness * Diagnosis of interstitial cystitis or overactive bladder syndrome * Prophylactic antibiotics started in the last 3 months and unwill…