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BMI: Body Mass Index; UI: Urinary Incontinence; SD: Sexual Dysfunction; ED: Erectile Dysfunction; PFD: Pelvic Floor Disorders; SUI: Stress Urinary Incontinence; UUI: Urge Urinary Incontinence; LUTS: Lower Urinary Tract Symptoms; QoL: Quality of Life; OAB: Overactive Bladder; POP: Pelvic Organ Prolapse; BPH: Benign Prostatic Hyperplasia, BS: Bariatric Surgery; LGB: Laparoscopic Gastric Bypass; RYGB: Roux-en-Y Gastric Bypass; ORSD: Obesity Related Sexual Dysfunction

Obesity is a global epidemic with increasing prevalence worldwide [1] Based on a definition of a body mass index (BMI) of 25-29.99 kg/m2 as overweight and BMI>30 kg/m2 as obese, the World health organization (WHO) estimates that approximately 1.9 billion and 600 million adults (age>18) are overweight and obese worldwide, respectively [2]. Obesity affects both sexes, all socioeconomic classes and both modern and developing populations. Not only does obesity have a significant I lmpact on quality of life, but also contributes to a large majority of healthcare costs due to associated comorbidities, including cardiovascular disease, cerebrovascular disease, diabetes and dyslipidemia [3]. Concordantly, it has been well-documented that disorders associated with obesity may improve or even resolve after BMI reduction, such as may be expected to occur after bariatric surgery, and the desire to improve medical comorbidities is the primary reason that patients seek bariatric surgery [4,5]

While the cardiovascular and metabolic sequelae of obesity are well-recognized, less commonly considered are the effects that obesity and weight loss may have on genitourinary function, including lower urinary tract symptoms (LUTS) and sexual dysfunction (SD) [6,7]. Additionally, while the American Society of Metabolic and Bariatric Surgery (ASMBS) clinical practice guidelines indicate that severe UI in the setting of BMI>35 kg/m2 is an indication to offer bariatric surgery, no such recommendations exist with regards to other bothersome urinary symptoms or SD despite their significant impact on quality of life [8]. While prior systematic reviews and meta-analyses have examined the role of bariatric surgery with regards to UI outcomes, few have examined other LUTS and none have discussed SD in a systematic review [9,10]. The current systematic review seeks to catalogue and summarize clinical research examining the deleterious effects of obesity on LUTS and SD and review sexual and urinary outcomes associated with bariatric weight-reduction surgery.

A systematic review of the literature was completed to identify English language articles pertaining to LUTS and SD in patients undergoing bariatric surgery published between 1990-2017 utilizing Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRIMSA) standards. Using PUBMED, search terms and nomenclature derivatives included “bariatric surgery and urinary symptoms,” “bariatric surgery and LUTS,” “bariatric surgery and SD,” “bariatric surgery and sexual function,” and “bariatric surgery and erectile dysfunction.” The PubMed function “cited references” and reference lists of all included articles were screened for any additional relevant articles. All titles and abstracts were screened for relevance. Case reports, review papers, articles without full-text availability, non-English language articles were excluded from final review. The remaining 43 screened articles were reviewed for eligibility by two reviewers. Ultimately, 32 retrospective and prospective studies of patients undergoing laparoscopic sleeve gastrectomy (LSG), Lap Band (LB), Roux-en-y Gastric Bypass (RYGB) or a combination with reporting on UI and/or SD were included in review and read in entirety by senior reviewer (Table 1). Please refer to Figure 1 for a complete illustration of our search protocol. Meta-analytic techniques were not applied to these data because of the heterogeneity of reported outcome measures and follow-up, as well as the lack of standardization of surveys and surgical procedures across studies.

Table 1: Summary of articles.

Figure 1: Study selection process and criteria for inclusion based on the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines (PRSIMA).

Separate surveys have been established to assess male and female sexual function. The most common verified questionnaires to evaluate SD are International Index of Erectile Function (IIEF), the Female Sexual Function Index (FSFI), the Brief Male Sexual Function Index (BSFI) and Impact of Weight on Quality of Life (IWQOL)-Lite questionnaire. Questions incorporate sexual satisfaction, desire/libido, quality of erections, and frequency of sexual intercourse. However, there has been a lack of consistency with regard to the use of these surveys across studies.

Of the 32 studies meeting the inclusion and exclusion criteria, 9.4% (n=3) and 90.6% (n=29) were retrospective and prospective in nature, respectively. 53.1% (n=17) evaluated LUTS, 25% (n=8) evaluated SD, and 21.9% (n=7) evaluated both LUTS and SD. Men were evaluated in 18.8% (n=6), 46.9% (n=15) evaluated women, and 34.4% (n=11) considered both. While the majority of studies utilized prospective validated surveys to assess genitourinary problems, there was significant heterogeneity. When considering questionnaires, 34.4% (n=11) used one validated questionnaire, 53.1% (n=17) used more than one validated questionnaire, 9.4% (n=3) used non-validated questionnaires and 3.1% (n=1) used no questionnaire (ICD-10 coding). Of the studies that utilized validated questionnaires, the most frequently used to assess LUTS or UI were the ICIQ 38.1% (n=8), PFDI 38.1% (n=8) and the IPSS 19% (n=4). When evaluating for SD the IIEF 57% (n=4) and the FSFI 57% (n=4) were the most common validated questionnaires. Please see Table 2 for a more detailed illustration of each reported validated questionnaire. The General Surgery or Bariatric Department was the most commonly cited investigator/author. They were involved in 71.9% (n=23) of studies, UroGyn/FPMRS Department in 28.1% (n=9), and Urology in 25% (n=8). Complete relevant article characteristics and data are summarized in Table 1.

Table 2: Validated Questionnaires utilized in the reviewed studies.

Epidemiology/Pathophysiology of Luts & Ui in the Bariatric Surgery Population

UI affects approximately 30 million US adults and can result in substantial distress, diminished quality of life, and limiting daily function [5]. The prevalence of incontinence has been reported to be as high as 60%-70% among morbidly obese women and 24% among obese men [5,14,38-40]. Epidemiological studies have shown that obesity is an independent risk factor for incontinence, reporting each 5-unit increase in BMI results in a 40-70% increase risk of UI [5]. There is limited data to assess the change in LUTS after weight loss in both men and women [6]. In the obese population, bothersome LUTS is a common development, and the consequential various urogenital complications are directly associated with obesity [4]. In men and women, a documented higher BMI and waist to hip ratio as well as a decreased level of physical activity were both associated with increased risk of LUTS [41]. Additionally, obesity as measured by waist circumference may be used as a predictor of LUTS [9]. A recent meta-analysis by Lee et al. [9] suggested that bariatric surgery results in the improvement or resolution of any UI in 56%, SUI in 47%, and UUI in 53% of patients. The etiology, mechanism and pathophysiology of bothersome LUTS in obese men and women is multifactorial; Diabetes mellitus (DM) is a condition often associated with obesity and a worsening of LUTS. Investigators have shown that obesity and concurrent type 2 DM result in detrusor over-activity, voiding dysfunction and increased incidence of LUTS [2,4].

More women than men undergo bariatric surgery according to a nationwide ten-year review (80.7% versus 19.3% respectively) [42], In the female population, obesity is a well-established and researched risk factor for UI [39,43,44]. In this group, UI is most frequently associated with obesity [26,34]. Osborn et al. [45] report as great as 71% of obese women seeking bariatric surgery complain of UI. Of these women, the rate of stress urinary incontinence (SUI) was 60%, urgency urinary incontinence (UUI) was 53%, and mixed incontinence was 42% [45]. As BMI rises there is an increase in intra-abdominal pressure, which results in a higher prevalence of pelvic organ prolapse (POP), overactive bladder (OAB) and SUI [37]. It follows that, improvement of intra-abdominal pressure afforded by weight loss thereby decreases mechanical stress on the bladder and pelvic floor and improves LUTS/UI [34].

While the relationship between obesity and urinary symptoms in male patients is less often considered, several authors have demonstrated an association between obesity and increased prevalence of BPH and LUTS defined by the IPSS [44,46,47]. It was reported by Kristal et al. [47] that each 0.05 increase in waist-to-hip ratio was associated with a statistically significant 10% increased risk of total (p<0.003) and severe (p<0.02) BPH. Additionally, in men it was demonstrated than increase in waste circumference, from <90 to >90 cm, was associated with a greater likelihood of higher IPSS (OR 1.68) [48].

Outcomes in Luts Following Bariatric Surgery

Female LUTS/UI outcomes

Most included studies grouped SUI and UUI together while describing the effects of obesity and weight loss surgery on UI in women despite different pathophysiology [32]. A study by Laungani et al. [26] of 58 obese women before and after gastric bypass showed an improvement in post-operative UI with the most significant reduction in SUI compared to UUI. Improvement in all three UI subtypes has been seen at 6 months postoperatively as measured on the ICIQ and IIQ-7, with a decreased incident of SUI by 61%, UU by 39% and MUI by 25% [2]. Surgically induced weight loss was associated with statistically significant improvement in UI, storage phase symptoms, condition-related QOL and POP symptoms. In a study of 56 women reporting preoperative incontinence, 88% (n=49) reported some improvement and 48% (n=27) reported complete resolution following bariatric surgery [27]. Rarely have women reported new onset of LUTS after undergoing bariatric surgery. It is reported that up to 1.3% experience de novo UI detected by both the ICIQ and BFLUTS questionnaires, as well as prolapse symptoms detected on the PFDI-20 questionnaire [27]. Interestingly, a study showed that when adjusted for weight loss there was a worsening in UUI, despite improvements of UI and SUI in female population [40]. While this could be due to long lasting effects of obesity (i.e. pelvic laxity or detrusor instability) it was not a common finding amongst studies. In a study of 77 women, Shimonov et al. [35] utilized 4 different validated questionnaires (ICIQ-UI, BFLUTS, PDFI, PSIQ) to assess the effects of bariatric surgery on UI in women. At 6 months, surgically induced weight loss was associated with improvement in UI, POP, filling symptoms, and QoL. A statistically significant, 51.7% of women described complete resolution in symptoms p<0.01 [35]. Scozzari et al. [34] demonstrated postoperative improvement in urinary score (14.6 vs. 8.3, p<0.001), with an overall decrease in UUI from 43.8% to 15.6% (p =0.029). When correlating with weight loss, one study showed that for each kilogram of weight loss there was a 0.05 improvement in the ICIQ score (p=0.03) [40].

Some studies utilized non-validated questionnaires or measured and reported UI and LUTS by other standards. For example, Knoepp et al. [23] sought to evaluate improvement in UI after bariatric surgery by evaluating CPT codes. They found that 62.4% of patients diagnosed with UI before their surgery, no longer had the same coding diagnosis at 5 years post operatively [23]. In another female predominant study, it was shown that there was an 80% reduction in patients medicated for incontinence [11]. Using self-report UI questions, Subak found significant (p<0.001) decreases in UI for women of 31% and 25% at 1 and 3 years [5]. Pad per day usage was also used a means of assessing improvement in UI, with a reported decrease in pads from 3.5/day to 1.75/day after bariatric surgery [17]. Interestingly, Talamas et al. [32] used urodynamic testing pre and post operatively to assess for UI. They reported a decrease in prevalence of UDS identified SUI after surgery (76.9% to 30.8%, p=0.01).

Male LUTS/UI outcomes

For Men, the IPSS was the most commonly utilized validated questionnaire to assess degree of LUTS and bother. Using the IPSS, Groutz et al. [20] showed a statistically significant improvement in storage phase LUTS among obese men who had undergone bariatric surgery. The postoperative total IPSS score decreased from 5.5 to 2.7 (p<0.001), and only improvement in storage phase symptoms was noted. Subjectively, 24% of men reported complete resolution of LUTS after surgically induced weight loss [20]. Similarly, a prospective study from Uruc et al. [36] identified improvements in IPSS from 4.5 to 1.91 (p<0.01). A positive correlation (62.8%) between post-operative BMI change ratio and IPSS change was noted. The same study also noted a decrease in ICIQ from1.82 to 0.32 (p<0.001) [36]. Using self-report UI questions, Subak found significant (p<0.001) decreases in UI 12% and 9%, at 1 and 3 years respectively [5]. Another study reported an improvement in number of voids/day, from a mean of 9.6/day preoperatively to 6.6/day post-operatively [4]. In a multicenter study by Luke et al. [6] men reported mild preoperative LUTS with mean IPSS score of 6.65, there was an observed improvement and/or resolution of these symptoms as early as 6 weeks postoperatively which was sustained at 1 year. Moreover, there were also statistically significant, p<0.01, improvements in all QoL, stream, urgency, intermittency, frequency. Contrastingly, 24% men with reported preoperative UI saw no improvement in LUTS/UI measured by IPSS (mean total IPSS preoperative 6.8 vs. postoperative 6.9) [40].

Epidemiology & Pathophysiology of SD in the Bariatric Surgery Population

Gender unspecified sexual dysfunction

While there has been less investigation, studies have shown that obesity can lead to SD [49]. Obesity is linked to a diminished sexual desire, poor sexual performance, and avoidance of sexual encounters. It has also been implicated as an independent risk factor for erectile dysfunction (ED) [13,50,51]. SD in obese patients is a common but complex condition that results in considerable personal distress and adversely affects health and quality of life [13,16, 19]. Ultimately the improvement in sexual satisfaction in bariatric patients in the postoperative period is multifactorial. Various aspects such as fewer physical limitations, self-esteem, improved erectile function, and increased sexual desire, all likely play a role.

Female specific SD

Female sexual dysfunction (FSD) is characterized by impairments in sexual response cycle and pain during or after intercourse [13,52]. Although a multifactorial issue, women seeking BS are at high risk of FSD and reported a lower sexual quality of life than obese controls [13]. Review of the literature shows that up to 60% of women seeking BS report FSD as defined by the FSFI [13,53]. On a preoperative study, women with incontinence reported a greater degree of SD compared to continent women [27]. Additionally, Steffan et al. [49] report that no sexual activity is most commonly attributed to being too tired/ not interested or not having a partner. When considering psychiatric causes, studies have found that anxiety impacted sexual desire, arousal, satisfaction and overall SD. Depression, however, was only associated with decreased desire [50]. In a preoperative evaluation, 11% of patients reported difficulty in engaging in sexual intercourse because of physical restrictions [21].

Male specific SD

More than one third of men (36%) presenting for BS reported ED [53]. Obesity appears to adversely impact male SF through several interlinked mechanisms [29]. A multi-institution study found that obese men most commonly attributed no sexual activity to physical problems [49]. Obesity and insulin resistance have been identified as causes of peripheral vascular disease secondary to subsequent endothelial dysfunction and atherosclerosis, both of which are known risk factors for ED [40]. Additionally, obesity has been associated with decrease in both total testosterone (TT) and sex hormone-binding globulin, as well as increase in estradiol in men [53,54]. Low T levels in obese men have been associated with increased estrogen production by adipose tissue, insulin resistance, low grade systemic inflammation as well as other risks associated with metabolic syndrome [29,51]. Hypotheses to the root cause of this dysfunction include low androgen levels, increased conversion of testosterone to estrogen in men and secondary to other comorbidities (i.e. arteriogenic ED as a result of peripheral vascular disease or long-standing hypertension) [55,56]. Few studies have been able to capture the complete effect of BS on SD in men, including the hormonal response [21].

Outcomes in SD Following Bariatric Surgery

Gender unspecified outcomes related to SD

Weight loss attained through BS improves body image and sexuality [57]. In a survey (non-validated) based study, in which only 28 of 94 patients who had undergone BS responded, 50% reportedly enjoy sex more, 44% report improved orgasms and 80% felt more attractive [57]. Improved SD and increased sexual activity in individuals who lost weight was associated with a variety of factors, including improved self-esteem, heightened libidinous body assessment of themselves, or their partners, and by fewer physical limitations [21]. Goietein et al. [57] reported an improvement in general satisfaction, desire, and erectile function with the BSFI scoring system, although results were not statistically significant [57].

Studies have reported a dramatic reversal of FSD after bariatric surgery, with resolution in 68% patients by 6 months and improvement to levels that mirrored controls [13]. FSFI scores improved from 24.2+5.9 to 29.4+4.3 after LGB and from 23.7+7.4 to 29+4.7 after RYGB [13]. In another study, 59% of women preoperatively reported SD with FSFI <24 and only 15% reported postoperative SD. Average FSFI index improved from 24+9.6 to 30+4.5 (p<0.006), with an independent increase in all FSFI parameters, except for desire [19]. All sexually active women reported significant postoperative improvements in SD, BFLUTS (decrease 0.3+0.9 to 0.1+0.6, p=0.011) and increased PISQ-12 (36 +7.3 to 39+5, p=0.003) [27]. A study of 82 female patients assessed postoperatively at 1 year with a non-validated questionnaire found that 63% of patients subjectively reported that they enjoyed sex more [21]. Improvements in SD were not found to be dependent on the amount of weight lost, and greater improvements in sexual function were noted with younger age, being married and worse preoperative SF [13]. Contrastingly, Olivera’s study of 36 women demonstrated that FSFI scores did not improve with weight loss across all domains: desire, arousal, lubrication, orgasm, satisfaction and pain [30].

Male specific SD outcomes and erectile dysfunction outcomes

The IIEF questionnaire was the most commonly utilized questionnaire to assess male SD (Table 1). In a study by Groutz et al. [20] the IIEF score was analyzed 3 months post-operatively in 53 patients who underwent sleeve gastrectomy. Questions regarding erectile function showed a significant improvement from 22.7 to 26.1 (p=0.02). There was also a statistically significant improvement in intercourse satisfaction (9.5-11.5) and overall satisfaction (7.9-8.9) (p<0.02) [20]. In addition to improved overall postoperative IIEF scores (54.85 vs. 61.21, p<0.001), BMI change was shown to be an independent predictor of changes in IIEF at 1 year post operatively on multivariate regression analysis (beta:-0.397, p=0.001) [29]. Kun et al. [24] utilized the IIEF, carotid/cavernosal intima-media thickness, endothelial function (L-arginine test), and cavernosal peak systolic velocity to analyze erectile function at one year postoperatively in 39 men who underwent RYGB. Significant improvements were seen for IIEF (17.3 vs. 23.8, p<0.05), cavernosal peak systolic velocity (23 vs. 37, p<0.05), and endothelial scores (6.1 vs 8.2, p<0.05) that mirrored weight loss one year after surgery. Furthermore, on multivariate correlation Kun showed that endothelial function was positively associated with change in IIEF (r=0.438, p<0.02) [24]. Interestingly, Kun extrapolates that beyond improvement in sexual function these patients also noted a significant improvement in vasculopathy, suggesting a functional recovery as well [24]. Using the BFSI, Dallal et al. [16] reports improvement of BFSI in 95 men who underwent GB with normalization of erectile function compared to age-matched subjects, unfortunately raw data regarding score change was not reported. Additionally, they comment that weight loss was an independent predictor of BSFI improvement. A prospective study demonstrated an increase in baseline BSFI score (40.2 to 43.9), with improvements in general satisfaction index, desire and erection, although this did not achieve statistical significance (p=0.064) [57]. Contrastingly, Ranasinghe et al. [40] report no improvement in total IIEF score despite weight loss. This was confirmed on multivariate analysis, and further reporting revealed an increase in men using PDE5-Inhibitors [40].

Studies have shown improvement in TT levels but no consistent changes in estradiol, sex hormone binding globulin, and gonadotropins [29]. Rigon et al. [54] report that 29 men who underwent bariatric surgery had notable improvements in postoperative TT levels (229.53 vs. 338.38). When compared to a control group there was no statistical difference in TT for the study group (p=0.099) [54]. Mora et al. [29] sought to better define this relationship. They found that serum T levels significantly improved at 1 year postoperative (256.36 vs. 508.01, P<0.01), as did FSH and Inhibin [29]. Interestingly, they saw no significant change in LH or estradiol levels [29]. While it has been acknowledged that psychological variables may also be a strong influence on sexual behavior and SD, there is limited study in the bariatric population to assess this.

Bariatric surgery associated weight loss appears to be consistently associated with improvements in LUTS and these improvements are not limited to urinary incontinence alone. Consequently, guideline recommendations should consider including LUTS as an indication for bariatric surgery in appropriately selected patients.

Similarly, SD may improve after weight loss surgery. Unfortunately, the data regarding SD is heterogeneous and often with poor follow up, necessitating further research be performed to assess gender-specific outcomes following bariatric surgery.

Ultimately, the accurate characterization of sexual and urinary outcomes following bariatric surgery necessitates multidisciplinary collaboration and, considering the increasing prevalence of obesity and the performance of bariatric surgery, future prospective studies should be pursued on an institutional level.