The following is a summary of “Efficacy of vaginal estrogen for recurrent urinary tract infection prevention in hypoestrogenic women,” published in the AUGUST 2023 issue of Obstetrics and Gynecology by Tan-Kim, et al.
Recurrent urinary tract infections (UTIs) in women with hypoestrogenism are commonly managed with vaginal estrogen therapy. However, evidence supporting its effectiveness was limited to small trials with restricted applicability. For a study, researchers sought to investigate the link between vaginal estrogen prescription and UTI frequency in a diverse group of women with hypoestrogenism over the subsequent year. Secondary objectives encompassed evaluating medication adherence and identifying predictors of post-prescription UTIs.
Conducted across multiple centers, the retrospective review enrolled women who received vaginal estrogen prescriptions for recurrent UTI prevention between January 2009 and December 2019. Recurrent UTIs were defined as having ≥3 positive urine cultures (at least 14 days apart) in the year preceding the index prescription. Participants were required to continue care within the Kaiser Permanente Southern California system for at least one year after the prescription. Exclusions comprised anatomical abnormalities, genitourinary malignancies, or mesh erosion.
Data on demographics, medical history, and surgical background were gathered. Adherence was gauged through prescription refill data. Low adherence referred to no refills, moderate adherence to one refill; and high adherence to ≥2 refills. Electronic medical records were used to extract data from the pharmacy database and diagnosis codes. A paired t-test compared pre- and post-prescription UTI rates, while multivariate negative binomial regression analyzed predictors of post-prescription UTIs.
The cohort included 5,638 women with a mean age of 70.4 (±11.9) years, a body mass index of 28.5 (±6.3) kg/m, and a baseline UTI frequency of 3.9 (±1.3). Predominantly White (59.9%) or Hispanic (29.7%) and postmenopausal (93.4%), the mean UTI frequency dropped to 1.8 (P<.001) in the year after the index prescription, representing a 51.9% reduction. During the subsequent 12 months, ≤1 UTIs were experienced by 55.3% of patients, while 31.4% experienced none.
Notable predictors of postprescription UTIs included ages 75 to 84 years (incident rate ratio, 1.24; 95% CI, 1.05–1.46) and over 85 years (1.41; 1.17–1.68), increased baseline UTI frequency (1.22; 1.19–1.24), urinary incontinence (1.14; 1.07–1.21), urinary retention (1.21; 1.10–1.33), diabetes mellitus (1.14; 1.07–1.21), and moderate (1.32; 1.23–1.42) or high medication adherence (1.33; 1.24–1.42). Intriguingly, patients with high medication adherence displayed more frequent post-prescription UTIs compared to those with low adherence (2.2 vs 1.6; P<.0001).
Among 5,600 women with hypoestrogenism and recurrent UTIs, vaginal estrogen prescription led to a 50% reduction in UTI frequency over a year. Age, baseline UTI frequency, urinary incontinence/retention, and diabetes were linked to higher post-prescription UTI risk. Paradoxically, women with high medication adherence experienced the smallest reduction in UTI frequency, possibly due to unobserved factors.