Urinary Incontinence: Epidemiology, Classification, and Diagnosis

Introduction

Urinary incontinence (UI), defined as the involuntary leakage of urine due to loss of bladder control, was described as early as ancient Egypt in the Imhotep Papyrus (c. 2700 BC). Hippocrates described involuntary urine leakage occurring after difficult childbirth. Avicenna also described urinary incontinence developing in women after childbirth as a result of damage to the integrity of the urinary bladder.

As the population ages, urinary incontinence is becoming an increasingly common problem. Individuals over 60 years of age are more likely to suffer from urinary incontinence than from cardiovascular diseases or other chronic conditions [1]. This disorder is more common among older adults than younger individuals. People are often reluctant to talk about urinary incontinence and seek medical attention too late. If left untreated, urinary incontinence can lead to social isolation, psychological problems, reduced self-confidence, and other adverse consequences.

The World Health Organization (WHO) classifies urinary incontinence as a so-called social disease. However, it is not only a social issue but also a medical, hygienic, and economic problem. In the United States, more than 12 billion US dollars are spent annually on the treatment of urinary incontinence [2].

Epidemiology

Worldwide, approximately 200 million people of all ages suffer from urinary incontinence [3]. In Lithuania, urinary incontinence affects nearly a quarter of a million men and women. According to scientific studies, up to 40% of individuals over 60 years of age experience urinary incontinence, while among those over 75 years of age, the prevalence may reach 80–90%. Survey data indicate that one in five Lithuanian women experiences urinary incontinence, yet only one-quarter of them seek medical attention. This condition is also common among men of all age groups, particularly older men. Urinary incontinence in men is more difficult to treat than in women, and this issue is often discussed too infrequently and too discreetly. It is estimated that urinary incontinence affects 10–30% of women and 1.5–5% of men over 65 years of age, whereas after the age of 80 the prevalence becomes similar in both sexes [1].

However, urinary incontinence can affect people of all ages, regardless of age, social background, or sex. This problem is also encountered in childhood (known as enuresis): 82% of 2-year-olds, 49% of 3-year-olds, 26% of 4-year-olds, and 20% of 5-year-olds experience involuntary daytime and nighttime wetting. Approximately 10% of seven-year-old children have primary nocturnal enuresis. Enuresis affects about 2% of adolescents aged 15 years [4].

Diagnosis

According to the 2002 definition of urinary incontinence proposed by the International Continence Society (ICS), urinary incontinence is an objectively demonstrable condition characterized by the involuntary leakage of urine that results in social, psychological, and hygienic problems.

Urinary incontinence, as a symptom, may occur in patients with urinary tract infections, including pyelonephritis and cystitis, where urinary frequency and involuntary urine leakage may mimic true urinary incontinence. Conversely, urinary incontinence may also occur as an independent clinical condition rather than as a symptom of another disease, and it has its own diagnostic code in the International Classification of Diseases, Tenth Revision (ICD-10).

Public health specialists working in municipal public health offices and community nurses are encouraged to pay greater attention to the growing problem of urinary incontinence and the stigma associated with it, as it affects not only health but also people's social and economic well-being. By developing partnerships with local communities, working closely with citizens and gaining their trust, they can promote the social integration of people living with urinary incontinence, reduce their social isolation, raise public awareness of the problems faced by affected individuals, their specific needs and preventive measures, and continuously encourage companies and organizations to improve working conditions, hygiene standards, accessibility of services, and everyday living conditions for people with special needs. According to the WHO classification, there are nine or even ten types of urinary incontinence (UI) [1,2,5,6]. The following are the most common types of urinary incontinence: Stress urinary incontinence (SUI). Urine leaks involuntarily, intermittently, and in small amounts when intra-abdominal pressure increases, such as during coughing, sneezing, lifting heavy objects, physical exercise, sexual intercourse, or laughing. This disorder may result from childbirth-related trauma, pelvic floor surgery, obesity, heavy physical exertion, chronic constipation, chronic cough, chronic diseases, or certain medications (particularly those with diuretic effects that increase urinary frequency). Stress urinary incontinence is more common in women. Men are more likely to experience post-micturition dribbling. Overactive bladder (OAB) / urge urinary incontinence (UUI). This condition is characterized by a sudden, compelling urge to urinate that cannot be postponed until reaching a toilet. It develops due to increased bladder irritability resulting from disturbances in neural regulation. In such cases, the bladder contracts involuntarily, causing a persistent and compelling urge to void (e.g., when hearing running water, being unable to unlock the door in time, or experiencing involuntary urine leakage). It is characterized by increased urinary frequency (>7 voids per day) and nocturia (more than once per night, or more than twice per night in older adults). Urinary tract infections are also included in this category because they may increase bladder sensitivity. In these cases, the bladder falsely signals the body that it needs to empty urgently, even when it is not full. Once the infection has been successfully treated or resolves spontaneously, bladder sensitivity decreases. Overflow urinary incontinence. Patients experience a false urge to urinate, a weak urinary stream, a sensation of incomplete bladder emptying, and the need to strain during micturition. This condition is more common in men. Overflow urinary incontinence usually develops due to urethral obstruction, which impedes urinary outflow and results in excessive urine accumulation within the bladder. The obstruction is most commonly caused by benign prostatic hyperplasia (BPH) or urethral stricture. Increased intravesical pressure in the overfilled bladder eventually overcomes the obstruction, resulting in involuntary urine leakage. Benign prostatic hyperplasia is almost unavoidable in aging men. Approximately 40% of men in their fifties, 50% in their sixties, 80% in their seventies, and nearly all men over 90 years of age have benign prostatic hyperplasia. These disorders not only cause urinary retention but also increase the likelihood of urinary incontinence in older age. Neurogenic urinary incontinence. This type develops secondary to diseases of the central or peripheral nervous system. It is most common in patients following trauma associated with sensory impairment, as well as in individuals with dementia, Alzheimer's disease, multiple sclerosis, Parkinson's disease, or stroke. These disorders disrupt neural pathways or impair their function, preventing the brain from transmitting appropriate signals to the bladder. In addition to continuous or intermittent urine leakage, overflow urinary incontinence may also occur as a result of obstruction or neurological damage. Postoperative urinary incontinence. This may occur, for example, following radical prostatectomy in men or hysterectomy in women. Mixed urinary incontinence (MUI). This refers to the coexistence of stress urinary incontinence and urge urinary incontinence, with one component usually predominating. The principal cause of urinary incontinence in older adults is reduced tone of the tissues of the genital and urinary tracts together with weakening of the pelvic floor muscles responsible for urethral support and compression [3]. The causes, risk factors, complications, and severity of urinary incontinence in older patients are presented in Figure 1. The most common causes of urinary incontinence in women: Pregnancy and childbirth. Additional body weight during pregnancy places increased pressure on the pelvic floor muscles, ligaments, and urinary bladder. Pregnancy hormones alter connective tissues and muscles, allowing them to stretch as the fetus grows. Consequently, the pelvic floor muscles become softer and more flexible to facilitate childbirth. As a result, the muscles and ligaments may become less effective at supporting the pelvic organs. During vaginal delivery, the pelvic floor muscles and ligaments are stretched further, and these tissues may undergo irreversible stretching. Menopause. As menopause approaches, estrogen levels decline, causing weakening of the pelvic floor muscles, and some women consequently lose bladder control. Urinary incontinence in women has numerous causes. In women over 50 years of age, it commonly develops secondary to menopause and hormonal changes, overweight or obesity, previous gynecological surgery (e.g., hysterectomy), various diseases (such as chronic bronchitis, stroke, and depression), and medication use. In younger women, urinary incontinence frequently develops following childbirth-related trauma or weakening of the urethral sphincter muscles. Participation in high-impact sports and heavy physical labor are also common causes of urinary incontinence [7–9]. The most common causes of urinary incontinence in men: Enlarged prostate. Benign enlargement of the prostate may slow or even completely obstruct urinary flow, resulting in a sudden and compelling urge to urinate. Prostate surgery. If the muscles responsible for urinary continence are damaged during prostate surgery, stress urinary incontinence may develop. One of the most common conditions encountered in clinical practice among men is acute urinary urgency. Patients frequently report that they "cannot hold their urine"; however, upon careful questioning, it often becomes clear that they are describing urinary urgency rather than true urinary incontinence. These are two distinct clinical entities. Urinary incontinence refers to continuous or involuntary urine leakage, whereas urinary urgency is characterized by a sudden urge to void that cannot be postponed long enough to reach a toilet. Acute urinary urgency usually develops secondary to inflammatory conditions such as prostatitis, cystitis, pyelonephritis, ureteritis, or urethritis. Therefore, when a patient presents with acute urinary urgency, inflammation affecting the bladder or prostate should be suspected. During the diagnostic evaluation, the first step is to identify the causative factor, which is usually a bacterial infection. Acute urinary urgency may also occur in patients with benign prostatic hyperplasia or overactive bladder. If no infection is identified but the patient continues to complain of urinary urgency, these disorders should be considered [3,6,10]. To establish an accurate diagnosis and select the most appropriate treatment, urodynamic investigations should be performed. In many cases, obtaining a detailed medical history and performing specific clinical tests (e.g., the cough stress test, Valsalva maneuver, or cotton swab [Q-tip] test) may be sufficient. However, urodynamic studies are essential before surgical treatment. Recommended investigations include cystometry to assess bladder capacity and detrusor muscle function, uroflowmetry to measure urinary flow rate, and determination of post-void residual urine volume. If indicated, urethral pressure profilometry may also be performed. Normally, urethral pressure should be approximately twice the intravesical pressure. When this pressure gradient is disturbed, urinary incontinence occurs. Therefore, after obtaining a detailed medical history, reviewing the voiding diary, performing a gynecological examination, assessing for pelvic organ prolapse, conducting the appropriate clinical tests and urodynamic investigations, the most suitable treatment strategy can be selected [1]. Dr. Rūta Mačiulytė Faculty of Medicine, Vilnius University Continued in Geriatrics News, 2019, No. 1.