Characteristics Associated With Recurrent Urinary Tract Infections: A Case-Control Study.

Objectives: Urinary tract infections (UTIs) are the most common bacterial infection in women. Recurrent UTIs (rUTIs) affect 2-10% of adult women and associated healthcare costs are estimated at $2 billion annually. The diagnosis is also associated with a significant impact on quality of life, daily activities, and mental health. Haylen, et al, 2009*, demonstrated that elevated post-void residual (PVR) was positively associated with rUTI; and pelvic organ prolapse (POP) stage was negatively associated with rUTI. Other risk factors include older age and medical comorbidities. The aim of this study was to identify characteristics associated with rUTIs among women seeking care for pelvic floor disorders at an academic tertiary urogynecology clinic. Identifying clinical characteristics associated with rUTIs may help provide insight with regard to identifying modifiable risk factors associated with this condition.

Methods: This was a retrospective case-control study of women presenting to an academic tertiary urogynecology clinic between June 2017 and 2022. Cases were women with rUTIs, defined as ≥2 UTIs in six months or ≥3 within one year, meeting urine culture criteria per CDC guidelines. Immediate postoperative UTIs, within six weeks of Urogynecologic surgery, were excluded. Controls were women with no culture documented UTIs. Cases were matched 2:1 to controls by age and body mass index (BMI). Demographic and clinical characteristics were compared between cases and controls and bivariate characteristics with p-values ≤0.2 and deemed clinically significant were assessed for independent association with rUTIs by multivariable regression.

Results: Of 435 subjects with a mean (SD) age of 72 years (11.8) and BMI 29.6 (6.7), 285 had rUTIs and 150 were matched controls. In unadjusted analyses, subjects with rUTIs were more likely to have a greater BMI, higher parity, be of black race, use less systemic hormone replacement therapy, had more urgency urinary incontinence, had a higher Urogenital Distress Inventory (UDI) score, a higher Charlson Comorbidity Index (CCI) score and higher PVR (all p< 0.05, Table 1). Despite matching, a statistical difference in BMI was noted between groups (30.2 vs 28.5, p< 0.01). Multivariable analysis (Table 2) revealed that prolapse beyond the introitus, (OR 0.28, 95% CI 0.13, 0.60), parity (OR 1.33, 95% CI 1.08, 1.64), CCI (OR 1.66, 95% CI 1.37, 2.03), and PVR >100cc (OR 4.05, 95% CI 2.01, 8.18) were associated with rUTIs.

Conclusions: In this ambulatory urogynecologic population, prolapse through the introitus was negatively associated with rUTIs, while parity, increased medical comorbidities and PVR were positively associated with rUTI. Perhaps independent of increased PVR, prolapse through the introitus mitigates the entry of microbial genera associated with rUTI into the bladder. Future research should seek an increased understanding of these factors associated with rUTI in order to implement effective preventative strategies.