The Lower Urinary Tract Symptoms (LUTS) involve all disorders of the bladder, bladder neck and urethra, including storage, voiding and post-voiding symptoms. Nowadays, there are many studies relating LUTS, obesity and metabolic syndrome (MS). 
Considering the lifestyle impairment and functional incapability, referred by obese women with LUTS, identify and possibly treat those symptoms, can decrease the risk factors, and the negative impacts on the quality of life, being a significant concern for public health. Based on these facts, our study aims to estimate the prevalence of voiding dysfunction on obese patients and compare them with the general population of the same age. Lastly, identify possible predictive clinic and urodynamic factors of those disturbs.

A prospective cohort study was performed. It was selected 94 female patients from the Obesity Program. They were selected aleatory and volunteered, without distinction of the skin color, from March 2018 until December 2019. The protocol was approved by the ethical committee under the number: 77105917.9.0000.5404.
Inclusion criteria: obese women with 18-55 years. After accepting participating in the study, they were asked to sign the inform consent.
Exclusion criteria: urinary tract infections, previous urethral surgery, pelvic cancer, and previous pelvic irradiation.
The patients were oriented to answer the International Consultation on Incontinence – overactive bladder syndrome (ICIQ-OAB) and the International Consultation on Incontinence Questionnaire - Short Form (ICIQ-SF). They were asked to answer in which daily situations they could leak urine, to determine the clinic diagnostic: 1)Never; 2)Before reaching the toilet; 3)When cough or sneeze; 4)While sleeping; 5)During physical activity; 6)After urinate and before get dressed; 7)No apparent reason; 8)All the time. Lastly, they were submitted to a physical exam and Urodynamics. 
On the physical exam, it was analyzed: blood pressure, weight, height, BMI (kg/m²), waistline and hip circumference; Pelvic Organ Prolapse (POP), and cervical circumference. After that were collected all lab tests for metabolic syndrome. The urodynamics consists of uroflowmetry, filling cystometry, stress test, leak point pressure, and pressure/flow study.
The results were compared to a systematic review of symptoms and urodynamics.

A total of 97 women signed the inform consent, three of them had a dipstick positive for UTI and were excluded. Other 10 women, after answering the questionnaires asked to leave the study. In the end, 84 women completed the study.
The mean age was 41,3 (+- 10,2) years, and the mean BMI was 45,11 (+-7,5) kg/m2. Four women were obese - Grade 1 (mean BMI 34,04kg/m2); nineteen were severely obese - Grade 2 (mean BMI 37,54kg/m2); sixty-one were morbid obese - grade 3 (mean BMI 48,11kg/m2). The clinical characteristics of these patients and the systematic review are described in table 1. The prevalence of Overactive Bladder (OAB) was 30,95%, which among them, 42,85% had Urgency Incontinence. The prevalence of Stress Urinary Incontinence (SUI) was 20,24%. The urodynamics diagnostics: detrusor overactivity (DO) in 33,33% of patients and 16,67% of SUI. There is no significant difference between the prevalence of voiding dysfunctions among the different obesity grade groups.
Pelvic organ prolapse (POP) was verified in 34,78% (19,56% Grade 1 and 15,21% Grade 2) of patients and did not vary among the obesity grade.

We performed a strict selection of obese patients to avoid bias due to a decrease in sex hormones in older patients, previous lower urinary tract surgeries, and other treatments. In the literature, we used as a control group, a systematic review of LUTS in women, and standard urodynamics data. Therefore we decided not to do a control group avoiding performing urodynamics in asymptomatic patients, decrease time work, and cost.
According to the literature, obesity is a well-known risk factor for Pelvic Floor Dysfunction (PFD), which includes POP, SUI, OAB, and Fecal Incontinence. Our data corroborate the literature showing that the prevalence of voiding dysfunction among obese patients is much higher than among non-obese women of the same age. The prevalence of OAB in healthy women, according to a systematic review conducted by I Milsom et al, varies from 8,7% to 11,9%. This prevalence is significantly lower than our data, which was 30,95%. Symptoms suggestive of OAB often profoundly compromise quality of life. This impairment was evidenced using the validated questionnaires ICIQ-OAB and ICIQ-SF. Both show a significant difference between normal women and those with OAB or SUI. Regarding SUI, the numbers are widely variable, but Hunskaar et al. have shown that the prevalence is around 6-10% of all women, less than half of the prevalence found in our study (20,24%). 
	When analyzing urodynamics parameters, it is interesting to notice that obese patients have an impairment of the cystometric capacity, especially the morbid obese ones. They have a smaller Maximum Cystometric Capacity (MCC), while normal women vary around 450-550ml, the grade 3 obese women have 325+-121,36ml. They also tend to go to toilet more often, since they refer a first sensation (normal: 100-250ml; grade 3: 80+-67,62ml), and first desire(normal: 200-330ml; grade 3: 140+-87,55ml) earlier then non-obese women.
In 2008, Hunskaar proposed that obesity increases the chances of SUI because of a higher intraabdominal pressure due to excessive fat, leading to an impairment of the pelvic musculature and innervation. Other studies seek to prove the relation between intraabdominal pressure and the prevalence of SUI, although the data is conflicting and weak. According to literature, normal intraabdominal pressure when the patient is standing is 30-50cmH2O. In our group, there was no statistically significant difference either between the intra-abdominal pressures of non-obese women and among the groups, besides the values were not related to the prevalence of SUI or DO. 
	Recently, emerged some evidence that Metabolic Syndrome (MS) is involved in the etiology of LUTS. It is believed that the physiological functioning of the bladder can be affected by an Autonomic Nervous System dysfunction caused by MS, although the literature is still conflicting. Bunn F et al. conducted a systematic review and concluded that those factors are not predictable of voiding dysfunction. Our data did not support a correlation with the risk factor for MS (DM, high blood pressure and waist circumference >= 80cm) individually. Probably, the combination of them can lead to voiding dysfunctions, even though our sample is not big enough to make those statistics analysis.
	A very interesting point of our study is the correlation with the clinical symptoms and urodynamic patterns. We strongly suggest accessing LUTS symptoms in all obese patients who seek medical treatment. These symptoms can play a major negative role in the quality of life of the patients, therefore the better we can understand them, the better we can possibly treat them.

Obesity is the main modifiable risk factor for pelvic floor dysfunctions. Obese women are more susceptible to develop SUI or OAB, independent of having DM or hypertension, compared to non-obese women, with or without the same comorbidities.