Risk Factors for Recurrent Urinary Tract Infections Among Women in a Large Integrated Health Care Organization in the United States

Background: Urinary tract infections (UTIs) occur commonly and often recur. However, recent data on the epidemiology of recurrent UTI (rUTI) are scarce.

Methods: Between 1 January 2016 and 31 December 2020, index uncomplicated UTIs (uUTIs) from office, emergency department, hospital, and virtual care settings were identified from the electronic health records of women at Kaiser Permanente Southern California. We defined rUTI as ≥3 UTIs within 365 days or ≥2 UTIs within 180 days. We determined the proportion of women with cystitis index uUTI who had rUTI, and we examined factors associated with rUTIs using modified multivariable Poisson regression.

Results: Among 374 171 women with cystitis index uUTI, 54 318 (14.5%) had rUTI. A higher proportion of women with rUTI vs those without rUTI were aged 18 to 27 or ≥78 years at index uUTI (19.7% vs 18.7% and 9.0% vs 6.0%, respectively), were immunocompromised, or had a positive urine culture result at index uUTI. In multivariable analyses, characteristics associated with rUTI included younger or older age (48-57 vs 18-27 years: adjusted risk ratio [aRR], 0.83 [95% CI, .80-.85]; ≥78 vs 18-27 years: aRR, 1.07 [95% CI, 1.03-1.11]), Charlson Comorbidity Index (≥3 vs 0: aRR, 1.12 [95% CI, 1.08-1.17]), and diabetes mellitus (aRR, 1.07 [95% CI, 1.04-1.10]). More frequent prior-year outpatient and emergency department encounters, oral antibiotic and oral contraceptive prescriptions, positive culture result at index uUTI, and antibiotic-resistant organisms were also associated with increased risk of rUTI.

Conclusions: The high risk of rUTI among women with cystitis is concerning, especially given previous reports of increasing UTI incidence. Current assessment of the epidemiology of rUTI may guide the development of preventive interventions against UTI.