Current Treatment of Overactive Bladder in Patients with Diabetes and Obesity
A review and assessment of five current research studies for the efficacy in managing overactive bladder syndrome, particularly in patients with metabolic disease.
October 2019
Volume 1, Issue 8

Assessing the Risk of OAB in Individuals with Metabolic Disease

Assessing whether a relationship exists between metabolic factors and likelihood of overactive bladder syndrome.

Urology. 2018;123:34-43

Evaluating the Potential Comorbidity of OAB and Obesity

Given the increasing prevalence of metabolic conditions in patients seeking relief for overactive bladder, investigators from the Symptoms of the Lower Urinary Tract Dysfunction Research Network (LURN) Observational Cohort Study, recruited individuals who were at least 18 years and presented to a urologist or urogynecologist for the treatment of lower urinary tract symptoms (LUTS).1,2

Eligibility for the cohort included the presence of daytime urinary frequency, nocturia, urinary urgency, incontinence or urine leakage, slow or weak stream, splitting (due to a distal urethral obstruction) or spraying (ie, most common in postmenopausal women who experience tight muscles around the urethral or a caruncle), intermittent urinary stream, urinary hesitance, straining to urinate, or dribbling at the end of the flow.

 

Women who are pregnant and individuals with a neurogenic condition or neurogenic bladder, a history of lower urinary tract or pelvic malignancy, or pelvic or endoscopic genitourinary surgery within the preceding six months, pelvic device or implant complications, sexually transmitted infections, major psychiatric disorders or conditions that would interfere with study participation, prostate biopsy within the previous three months, or Botox injection to the bladder or pelvic structures within the preceding 12 months, were excluded.1,2

Patient data was collected at baseline, which included: urinary symptoms, medical history, medication use, blood pressure, and adiposity (both general/overall and central), diabetes, dyslipidemia, and hypertension. Study participants were followed for one year.1

Central obesity, a key component of the metabolic syndrome and a predictor of cardiovascular risk, 3,was assessed based on waist circumference measurements, as defined by three measures: the Adult Treatment Panel III Guidelines (ATP III) (≥ 102 cm for males, ≥ 88 cm for females), the International Diabetes Federation (≥ 94 cm for white males, ≥ 80 cm for white females), and waist circumference as a reflection of central obesity.

General obesity was defined as having a body mass index (BMI) of 30 kg/m2 or higher, and overweight was defined as a BMI of 25-29 kg/m2. The study used the LUTS Tool, with a one-week recall period, to assess urinary symptoms.

The investigators reported amassing baseline data from 920 patients who had provided complete information on metabolic factors and responses to at least 14 questions on the LUTS Tool. The cohort was balance between the sexes (n = 456 men, and n = 464 women). The mean age of the cohort was 59.1 ± 13.9 years. Eighty-five percent of the patients were Caucasian. Most of the cohort exhibited central obesity, 43.4% showed general obesity, and 76.5% fell into the overweight range.

More than half (65.2%) were diagnosed with hypertension, 31.5% had hyperlipidemia, and 17.1% had diabetes. Approximately one-third of the cohort showed no signs urinary incontinence, whereas 63.4% had overactive bladder (OB). Among those with OB, 66.4% had urgency urinary incontinence.1

Multivariable logistic regression models revealed an association between higher waist circumference and higher risk for any urinary incontinence (odds ratio [OR] 1.16 per 10 cm increase, P = 0.008) in both sexes. Waist circumference was also associated with OAB in female participants (OR 1.25 per 10 cm increase, P = 0.003), but not in the men (OR 1.02 per 10 cm increase, P = 0.73). Higher waist circumference was also associated with OB with urgency urinary incontinence (OR 1.23 per 10 cm increase, P = 0.006), increased frequency (OR 1.16 per 10 cm increase, P = 0.009), at least one nocturia episode per night (OR 1.16 per 10 cm increase, P = 0.035), and at least two nocturia episodes per night (OR 1.12 per 10 cm increase, P = 0.016).

As was the case with central obesity, general obesity, as defined by higher BMI, was associated with any urinary incontinence (OR 1.20 per 5-unit increase, P = 0.006) and urgency urinary incontinence (OR 1.31 per 5-unit increase, P < 0.001) in both sexes and with stress urinary incontinence in female participants (OR 1.32 per 5-unit increase, P = 0.009). Higher BMI was also associated with OB in women (OR 1.38 per 5-unit increase, P < 0.001) but not in men (OR 1.05 per 5-unit increase, P = 0.59). Among participants with OB, higher BMI was associated with urgency urinary incontinence (OR 1.26 per 5-unit increase, P = 0.006).

Multivariable regression models were used to assess the data, and revealed a newly identified association between elevated lipids and at least two nocturia episodes per night (OR 1.46, P = 0.035 in the central obesity model; OR 1.48, P = 0.021 in the general obesity model). No relationship between LUTS and metabolic factors such as diabetes or hypertension were evident. Older age, female sex, and African American race were also associated with multiple urinary complaints.1

One the basis of these results, the investigators concluded that obesity is a key modifiable metabolic risk factor for urinary incontinence and overactive bladder syndrome. Since data was not collected for fasting glucose, hemoglobin A1c, high-density lipoprotein cholesterol, or triglyceride levels, the ability to determine an association with type 2 diabetes could not be made.

There were no financial conflicts reported by any particupating authors. This study was underwritten by a grant from the National Institute of Diabetes and Digestive and Kidney Diseases.

Expert Commentary on Metabolic DIsease and Overactive Bladder Syndrome

This study by Lia et al lends further credence to a recognized relationship between bladder dysfunction and factors arising from metabolic syndrome.1 While a relationship between body mass index (BMI) and female urinary incontinence has been demonstrated in multiple studies, the evaluation of central (abdominal) adiposity, specifically, has not been as common or consistently pursued. This is somewhat surprising, as central obesity is a well-known constituent of the metabolic syndrome and more predictive of cardiovascular disease risk than an elevated BMI.5,6 

The findings reported in this study demonstrate a strong association between central obesity and overactive bladder syndrome in women but not in men, bringing into question the possibility of a contribution of hormonal factors as the rationale for difference outcomes between the sexes. Similarly, central obesity has been associated with increased abdominal pressure which may weaken the pelvic support mechanism and lead to stress urinary incontinence, pelvic organ prolapse, and urge urinary incontinence.7

Systemic neuroendocrine, vascular, or inflammatory mechanisms have, likewise, also has been proposed to account for the relationship. The data presented by these researchers shows that obesity is a key, modifiable metabolic factor that is associated with overactive bladder syndrome as well as urinary incontinence of all types. We would be remiss if we didn’t mention that this was a cross-sectional study design, so precludes the ability to draw conclusions regarding causality or temporality.

That said, weight reduction can (and should be) recommended as an initial therapeutic strategy to any patients at-risk in order to reduce the possible development, progression, and adverse quality of life impact that comes with overactive bladder and urinary incontinence. 

Commentary

Next Article:
Patient-Reported Drug Preferences in Management of OAB Symptoms
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