Introduction and hypothesis: Recurrent post-coital urinary infection (rUTI)-usually cystitis-is a common entity among otherwise healthy young women. However, little is known about the possible influence of genital anatomical variations. Only a shorter urethral meatus-anus distance has been described as a risk factor. The aim of this study was to evaluate our hypothesis that a shorter urethra-vagina distance is involved in the etiology of post-coital urinary infection.
Methods: In this prospective case-control study, 61 young women aged between 18 and 40 years with an acute post-coital UTI and a history of intercourse-related rUTI were consecutively recruited between January 2013 and February 2018. Fifty-six age-matched, sexually active women with no history of UTI served as controls. Perineal measurements included the distances between the clitoris-urethra (C-U), urethra-vagina (U-V), urethra-anus (U-A) and perineum. Demographic and sexual behavior characteristics and the morphology of the urethral meatus were also noted. Univariate analysis compared variables between groups. ROC analysis was used to define the efficiency of perineal measurements in predicting outcome. Odds ratios and 95% confidence intervals for UTI-predisposing variables were estimated using logistic regression analysis.
Results: The U-V and U-A distance was shorter in patients compared with controls [median (interquatile range): 16 mm (14-18) vs. 21 mm (19-23) and 51 mm (47-53) vs. 59 mm (55-62), respectively, p < 0.001]. The U-V performed better in ROC analysis than the U-A distance (AUC 0.952 vs. 0.875, p = 0.023). The only statistically significant parameters in multivariate analysis influencing UTI were BMI (OR: 0.702; 0.510-0.967, p = 0.030) and U-V (OR: 0.297; 0.161-0.549, p < 0.001).
Conclusions: Our results indicate an association between shorter urethra-vagina distance and post-coital rUTIs.
Keywords: Anatomy; Cystitis; Female; Meatus; Recurrent UTI; Urethra.