Probability of Recurrent UTI in Women

Urinary tract infections have a high recurrence rate among women: approximately 27% of women who have a first UTI will have a second within 6 months, and about 3-5% develop recurrent UTIs (defined as 3+ infections in 12 months or 2+ in 6 months). The recurrence rate increases with each subsequent infection.

Recurrent UTIs most commonly involve reinfection with a new organism (about 80% of recurrences) rather than relapse with the same organism. Risk factors for recurrence include sexual activity, spermicide use, history of UTIs, post-menopausal status (due to changes in vaginal flora), genetic factors, and pelvic floor dysfunction.

Management of recurrent UTIs has evolved. Options include behavioral modifications (post-coital voiding, adequate hydration), vaginal estrogen therapy for postmenopausal women (which reduces recurrence by about 50%), low-dose prophylactic antibiotics (continuous or post-coital), self-start therapy (providing antibiotics for the patient to begin at symptom onset), D-mannose supplements, and cranberry products (with modest evidence of benefit). Antibiotic stewardship is increasingly important as resistance patterns worsen: about 20-30% of urinary E. coli are now resistant to trimethoprim-sulfamethoxazole.