Menopausal Syndrome
A 2012 review of the literature on the epidemiology of UI in women and the effects of HRT on urinary leakage found that UI was a common symptom during menopause.33 Decreased estrogen concentrations associated with menopause have been considered to be responsible for the increasing prevalence of SUI in aging women, possibly because vaginal tissue is weaker in postmenopausal women than in premenopausal women and thus becomes a risk factor for the deterioration of continence mechanisms and consequently the efficacy of anti-incontinence surgery.34, 35 Although menopausal syndrome is a recognized risk factor for SUI, scant study evidence describes the effects of menopausal syndrome on surgical outcomes. A retrospective study from Turkey that investigated mesh erosion after tension free vaginal tape (TVT) and transobturator tape (TOT) found that menopausal status was a statistically significant factor in patients with mesh erosion, but was no longer a significant independent risk factor after multivariate analysis.36 In contrast, our study found that patients who had a history of menopausal syndrome within 1 year prior to the index operation were more likely to develop surgical complications. Moreover, menopausal syndrome or HRT were significantly associated with the risk of 5-year surgical complications (aHR, 1.794; p=0.0390), although the association was not significant in patients aged ≤65 years (aHR, 2.164; p for interaction=0.3750). Estrogen increases angiogenesis, which is important for nourishing vaginal tissue. However, a negative correlation has been observed between angiogenic activity and mesh-induced inflammation in mice implanted with steroid-coated polyvinylidenfluoride (PVDF) meshes.37 At menopause, decreased estrogen levels lead to a reduction in angiogenesis and therefore poor nourishment of vaginal tissue, which would increase the possibility of surgical complications.
Hormone Replacement Therapy
International guidance recommends conservative therapies as the first-line management of women with SUI, such as lifestyle changes and behavioral therapies, weight loss, and supervised pelvic floor muscle training.11, 12 Estrogens are believed to be beneficial in the treatment of SUI; starting estrogen replacement soon after menopause may be effective in preventing or delaying the onset of SUI.35, 38
HRT is a common medical treatment used to supplement women with hormones that are lost during the menopausal transition. Conventional HRT includes an estrogen and progesterone component to relieve the menopausal syndrome.39 In our study, patients with diagnosed menopausal syndrome who used HRT within a year prior to midurethral sling surgery had a significantly higher risk of surgical complications at 5 years following midurethral sling surgery for SUI compared with their counterparts who did not have these risk factors. As patients diagnosed with menopausal syndrome commonly receive HRT to relieve their symptoms, it is difficult to distinguish between the effects of HRT and aging-related menopausal syndrome upon the risk of surgical complications associated with midurethral sling surgery. Although vaginal estrogen may be effective in preventing or delaying SUI, no evidence has shown that oral estrogen has benefits in SUI patients. A retrospective study in 2018 had found that the use of systemic estrogen may increase the SUI risk.40Estrogens are known to stimulate collagenase activity, which may lead to degradation of total collagen, especially the most supportive type I collagen, which may be replaced by weaker immature collagen.40 The lack of mature collagen might lead to inadequate support of the vaginal and pelvic structure, especially postoperatively, increasing the possibility of surgical complications such as urine retention.