Strong evidence of an association between hysterectomy and urinary incontinence

Sir,

We would like to express our gratitude to the authors for publishing their important and thought-provoking study on risk of urinary incontinence (UI) subsequent to hysterectomy.¹

We agree with the authors on the need for a thorough investigation into long-term complications after hysterectomy including risk of subsequent urinary incontinence.

However, we have concerns regarding the study's methodology, which may account for the study's finding of no association between hysterectomy and UI, in contrast to the robust evidence supporting such an association in previous well-designed population-based studies.^{2, 3}

First, we note that women in the hysterectomy group with a pre-existing diagnosis of UI were excluded (7.8%), while no such exclusions were applied to the control group. This creates a substantial imbalance between the compared groups, as the hysterectomy cohort is selectively screened to include only women without UI at the time of surgery. While we understand the authors' intention to isolate the effect of the hysterectomy itself by excluding pre-existing symptoms, such an approach necessitates similar exclusion criteria for the control group to ensure comparability between the two groups.

Secondly, there is a notable difference in the timeframes during which women in the two groups were eligible to be diagnosed with UI or to undergo UI surgery. The study includes women up to the age of 54, while the mean age for hysterectomy in the group is 45 years. This leaves limited follow-up time after hysterectomy and may skew the risk of being diagnosed or undergo surgery for UI in the two groups. It does not appear that the authors have adjusted for timeframes or differences in age distribution between the two groups.

The authors themselves acknowledge that the evidence on the association between hysterectomy and UI is conflicting. However, this is largely due to two smaller studies of questionable nature including one study following women for 30 days post hysterectomy only⁴ and one study excluding all women undergoing a UI surgery post hysterectomy (5%) in the hysterectomy group.⁵ In contrast, larger, well-designed studies have consistently found a significant association,^{2, 3} providing robust evidence of the increased risk of UI following hysterectomy.

Given the substantial evidence supporting an association between hysterectomy and subsequent UI, it is essential for gynecologists to be aware of this risk and to discuss it with patients as part of the decision-making process when considering hysterectomy.