Methods: We conducted a retrospective cohort study of women age ≥ 18 years who presented for treatment of a UTI at Oregon Health & Science University ambulatory care clinics between 2011-2016. Pregnant women as well as those with a recent urinary catheter, genitourinary (GU) procedure, or hospitalization were excluded. The outcome was defined as the first episode of rUTI within one year of an index UTI. Demographics, biologically relevant comorbidities, and the antibiotic prescribed to treat the index UTI were evaluated as potential risk factors for first rUTI using multivariable logistic regression. A best subsets approach was used to determine the most parsimonious model.
Results: 3,632 patients met inclusion criteria. The mean age of the cohort was 50 ± 20 years and 12% had a diabetes diagnosis. To treat their index UTI, 36% of women were prescribed fluoroquinolones, 33% sulfamethoxazole and/or trimethoprim, and 25% nitrofurantoin. Over the study period, the cumulative incidence of first rUTI was 16% (95% confidence interval (CI): 15.3%, 17.7%); 35% (95% CI: 31%, 39%) of these patients had >1 rUTI. Our model identified age (Odds ratio (OR): 1.02; 95% CI: 1.01, 1.02), urban residence (OR: 1.78; 95% CI: 1.28, 2.57), and neurologic disease diagnosis (OR: 1.46; 95% CI: 1.13, 1.89) affecting GU function (e.g., multiple sclerosis or spinal cord injury) as significant, independent risk factors of first rUTI after adjusting for the confounding effects of diabetes, obesity, and history of stroke or other cerebrovascular disease.
Conclusion: Diagnosis of neurologic disease that impacts GU function, age, and urban residence were identified as significant risk factors for first rUTI. The antibiotic selected to treat patients’ index UTI was not a significant risk factor for first rUTI. Future studies are needed to identify risk factors beyond what is currently captured discretely in the electronic health record to address critical gaps in our understanding of risk factors for rUTI.
M. R. Elman, None
D. T. Bearden, None
J. C. McGregor, Merck: Grant Investigator , Research grant .