URINARY INCONTINENCE IN THE ELDERLY FEMALE

Urinary incontinence is a common condition in the rapidly aging U.S. population. The incidence and prevalence of incontinence is increasing in the elderly, in no small part due to the greater recognition of its signs and symptoms and the subsequent negative impact on quality of life. Elderly women are different from their younger counterparts, due not only to several physiologic changes in the urinary tract, but also to concomitant morbidity and polypharmacy. While the elderly have the same treatment options as younger women, they may experience a greater incidence of adverse events due to urologic and nonurologic factors. The objective of this review is to elucidate the unique changes in the elderly population and summarize the treatment options. (Annals of Long-Term Care: Clinical Care and Aging 2009;17[10]:41-45)
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Introduction

In 2003, a panel convened by the International Continence Society (ICS) defined the signs, symptoms, urodynamic observations, and conditions associated with lower urinary tract symptoms (LUTS) and urodynamic studies.¹ The symptoms of LUTS were categorized into several distinct types of incontinence. Stress urinary incontinence (SUI) refers to involuntary leakage on effort, exertion, or other increases in intra-abdominal pressure.¹ Urge urinary incontinence (UUI) is involuntary leakage accompanied or immediately preceded by urgency, while mixed urinary incontinence (MUI) refers to incontinence with symptoms of both SUI and UUI.¹

Several emerging trends are germane to a discussion of incontinence in the elderly woman. First, the population is aging. A report by the U.S. Census Bureau noted that, while the total U.S. population has increased twofold in the past century, the population of Americans age 60 years and older increased tenfold to 35 million in the year 2000.² Additionally, the number of Americans over age 80 is expected to increase by nearly 70% from 2000 to 2030. Second, incontinence is an increasingly common problem in the aging population. An analysis of more than 3100 responses to a medical questionnaire showed that the estimated incidence of incontinence increased steadily with age, especially through ages 25-29 and 45-49.³ By the age of 59 years, 30% and 18% of individuals were estimated to have had one or more episodes of incontinence in general and incontinence as defined by the ICS, respectively.

The prevalence of different types of incontinence is also considerable. A U.S. national telephone survey using a clinically validated interview of 5204 adults revealed that the prevalence of UUI in women increased with age from 2.0% to 19%, with a marked increase after 44 years of age.⁴ The prevalence of SUI has been reported to be as high as 40% in women after age 70, with one-third of these women classifying their incontinence as severe.^5,6

Additionally, the most common type of incontinence may change with age. Once the prevalence rates of different types of incontinence were stratified by frequency and age, 55% of women under 60 years of age were found to have pure SUI, while 20% and 25% had UUI and MUI, respectively. In comparison, SUI accounted for only 30% of incontinence cases in the over-60-year-old female, while UUI and MUI each accounted for 35% of cases.⁷

Incontinence may also make a significant impact on a woman’s quality of life (QoL). In a national sample of more than 3400 women culled from the National Survey of Self-Care and Aging, urinary incontinence was independently and positively associated with poor self-rated health after adjustment for age, comorbidity, and frailty.⁸ When cross-sectional data from a population-based cohort of more than 2100 middle-aged or older women were analyzed, more than 28% reported weekly incontinence.⁹ SUI, UUI, and MUI were reported in 37%, 31%, and 21%, respectively, and MUI was associated with a greater impact on QoL than either SUI or UUI, independent of age, race, health, or incontinence severity.

Physiological Changes with Age

The development of urinary incontinence in elderly individuals is a multifactorial process, as several age-related changes may predispose or potentiate incontinence. On the cellular level, the bladder may undergo several adaptations. Elbadawi et al¹⁰ proposed that a “dense band pattern” represents a structural norm of the aging detrusor. The dense band pattern was characterized by overall normal configuration of muscle cells and cell junctions, sarcolemma (muscle cell membrane) dominated by dense bands with depleted caveolae in interposed zones, and slight widening of spaces between muscle cells with little collagen content. The same group also identified a “dysjunction pattern” in biopsies from elderly patients with urodynamic detrusor overactivity.¹¹ This pattern was characterized by moderately widened intercellular spaces, scarce intermediate muscle cell junctions, abundant distinctive protrusion junctions, and ultra-close cell abutments. Superimposed widespread degeneration of muscle cells and axons was noted in a subgroup of patients with impaired detrusor contractility.

Structural changes of the urethra may also be seen with advancing age. As the estrogen content in the vaginal and periurethral tissues decreases, vascularity in the urethral submucosa may decrease and potentially affect the watertight urethral seal.¹² The morphology of the urethra may likewise be affected. The number and density of urethral striated muscle fibers at the bladder neck, and along both the dorsal and ventral walls of the urethra, declines with age.^13,14 Apoptosis has been proposed as a potential mechanism for the dramatic age-related decrease in the number of striated muscle cells.¹⁵ With aging, there also appears to be an increase in connective tissue in the paraurethral area.^16,17

Additionally, several urodynamic changes are observed in the aging bladder. The maximal urethral closure pressure appears to decrease with age, and in one study of incontinent women over 55 years of age, 77% had an incompetent urethra.^18,19 Bladder sensation and the ability to postpone voiding are decreased, while the incidence of unstable detrusor contractions increases.¹⁸ Likewise, the incidence of detrusor hyperactivity with impaired contractility increases in the elderly and may be the second most common (33%) cause of incontinence in this population.²⁰ In institutionalized patients, incontinence may be even more complex. Of 605 institutionalized patients (mean age, 89 yr) who underwent urodynamics, detrusor overactivity was the predominant cause in 61%, with concomitant impaired detrusor contractility present in half of these patients.²¹ SUI was diagnosed in 21%, and at least two coexisting probable causes of incontinence were identified in 35% of the study population.

Nonurological Changes in the Elderly

The elderly population may be faced with a number of nongenitourinary factors that may predispose them to developing urinary incontinence or may exacerbate preexisting incontinence. DuBeau²² has effectively categorized these factors into: comorbid diseases, neurological and psychiatric conditions, functional and environmental factors, and medications. Common comorbid conditions include diabetes, which can induce polyuria through an osmotic diuresis, and congestive heart failure, which may precipitate fluid overload and excess urinary output. Additionally, poorly controlled diabetes may be associated with neuropathy and subsequent detrusor overactivity or diabetic cystopathy, which may result in poor emptying and chronic bladder overdistention. Other conditions such as degenerative joint disease and severe constipation may also be associated with urinary incontinence.²² Nocturnal urinary frequency and an increased volume of urine excreted at night are additional common findings in the elderly, often presenting even in the absence of lower-extremity edema and heart failure.¹⁸ Furthermore, the increased incidence of such age-associated sleep disorders as insomnia, obstructive sleep apnea, dyspnea, and medication side effects serves to contribute to the nocturnal frequency.^18,23

Suprapontine insults, such as stroke and closed head injury, may result in loss of detrusor inhibition and subsequent detrusor overactivity. While dementia has often been associated with incontinence, Resnick and Yalla¹⁸ have suggested that there are multiple causes of detrusor overactivity in the elderly in the absence of dementia. Conditions such as normal aging, cervical disk disease, Parkinson’s syndrome, and subclinical lower urinary tract obstruction may all be responsible for urinary incontinence.

Several classes of medications can influence bladder storage and emptying, and subsequently may have an impact on incontinence in the elderly.^22,24,25 Antihypertensives are especially concerning. Alpha-adrenergic agonists can increase bladder outlet resistance and contribute to voiding difficulty, while beta-adrenergic blockers decrease urethral closure and may lead to SUI. Calcium channel blockers reduce bladder smooth-muscle contractility, while angiotensin-converting enzyme (ACE) inhibitors induce cough and may worsen SUI. Cholinesterase inhibitors, such as those frequently used for Alzheimer’s disease, can precipitate UUI, while medications with anticholinergic properties such as antidepressants can impair bladder contractility and potentiate voiding difficulty and overflow incontinence. Additionally, sedatives may contribute to confusion and secondary incontinence. Furthermore, alcohol, caffeinated beverages, and diuretics can contribute to a diuresis with rapid bladder filling.

Functional and environmental factors may ultimately play the largest role leading to incontinence in the elderly. Poor mobility from lower-extremity injury or degenerative disk disease may significantly increase the time period from sensing the urge to urinate and reaching the commode. Conversely, weekly diurnal urinary frequency and UUI have been shown to be associated with a 26% increase in falls and a 34% increase in fractures.²⁶ Loss of eyesight, along with loss of balance and equilibrium, potentially brought on by medications or previous strokes, may lead to falls and incontinence.¹⁸ Finally, inaccessible toilets and lack of caregivers can also contribute to incontinence.²²

Treatment Options

Both UUI and SUI may respond to nonpharmacologic and nonsurgical measures. The simplest measures may involve judicious limitation of fluids at bedtime and providing a nearby bedside commode.¹⁸ Bladder training with scheduled urination for cognitively intact women and “prompted voiding” for cognitively impaired patients are often successful at restoring continence. Nocturia and nocturnal diuresis may be improved by mobilizing lower-extremity edema during daytime hours by incorporating compression stockings, elevating legs during the daytime, and potentially employing a rapidly acting diuretic in the afternoon.¹⁸ Additionally, bladder diaries may be useful teaching tools to focus patients on their voiding habits and fluid intake.

The addition of pelvic floor exercises with biofeedback may be a useful adjunct to behavioral therapy. In a study of women ages 52-92 years with UUI or urge-predominant MUI, Burgio et al²⁷ found a significant reduction in incontinence episodes with biofeedback-assisted behavioral treatment as compared with placebo. In the same population, behavioral training combined with anticholinergic medication was associated with a reduction in UUI episodes in over 80% of the women.²⁸ This improvement was seen regardless of whether the behavioral training or the medicine were started first. Due to quality differences and generally small sample size of the available studies, an attempted meta-analysis found no evidence to suggest that one pelvic muscle training is better than another in this population.²⁹ Zinkgraf et al³⁰ recently suggested a role for percutaneous tibial nerve stimulation for the treatment of elderly patients with UUI who were refractory to behavioral modification and pharmacotherapy. Although promising, neuromodulation in this population requires additional research.

Pharmacologic Treatment of UUI

Antimuscarinic medications are the mainstay of pharmacologic therapy for UUI and other symptoms associated with overactive bladder. The available drugs in this class (oxybutynin, tolterodine, solifenacin, darifenacin, trospium, and fesoterodine) all block the muscarinic receptor but differ in several ways. While most of the agents are tertiary amines, trospium is a quarternary amine and does not cross the blood-brain barrier. Oxybutynin is available in transdermal patch and transdermal gel applications. This application bypasses drug metabolism in the liver and may be associated with a lower incidence of adverse events, such as dry mouth and constipation. Oxybutynin and tolterodine are available in immediate-release preparations that are administered 2-3 times per day. All of the medications are available in extended-release, once-daily preparations.

While effects on M3 receptors (primary mediators of detrusor contractility) are universal to all available antimuscarinics, their effects at other receptors may vary.^31,32 The M1 receptor is found in the cerebral cortex, hippocampus, eyes, and salivary glands, with blockade-impacting memory, cognitive function and saliva and tear production. M2 receptors are located in cardiac muscle, eyes, bronchial smooth muscle, hippocampus, and hind brain. Blockade of these receptors may cause tachycardia and may impact on tear secretion and bronchodilation. In addition to affecting bladder motility, blockade of the M3 receptor may affect visual accommodation, as well as saliva and tear secretion. While all of the antimuscarinic medications differ in their selectivity for the M3 receptor, it is currently not clear whether increased selectivity results in greater clinical efficacy.³³

Effects and tolerance of antimuscarinic medications in the elderly population have been good. In a retrospective analysis of pooled data from four studies, Wagg et al³⁴ reported that continence was restored in nearly 50% of patients older than 65 years of age taking solifenacin 5 mg and 10 mg (P < 0.001 for both doses vs placebo). Most of the adverse events (dry mouth, constipation, urinary tract infection) were mild to moderate in nature and did not result in treatment discontinuation. Side-effect profiles are especially important to consider in the elderly, as antimuscarinic side effects may be additive with those of other medications or may counteract other medications. When immediate-release oxybutynin was administered to patients age 65-76 years, a significant impairment was noted in memory and speed on cognitive testing.³⁵ On the other hand, 150 subjects age 60 years and older taking darifenacin showed no significant changes over placebo in 13 of 15 endpoints assessing memory and cognitive function.³⁶

Surgical Treatment of SUI

The use of surgery to correct SUI has been increasing. Data from the National Hospital Discharge Survey indicated that the number of women who had undergone SUI surgery each year increased from 48,345 in 1979 to 103,467 in 2004.³⁷ Surgical treatment for SUI in the elderly woman in particular has likewise been on the rise. Analysis of data from a 5% national random sample of female Medicare beneficiaries age 65 years or older revealed that the overall number of surgical procedures increased from 18,820 to 32,480 during the 10-year period between 1992 and 2001.³⁸ The types of interventions have changed during that time period. In 1992 and 1995, needle suspensions were the most popular procedures, while urethral bulking agents were the most popular in 1998.³⁸ A drastic increase in the number of sling procedures occurred from 1995 to 2001, a finding potentially related to the rise in popularity of the midurethral sling procedure.

Several studies have reported the outcomes of anti-incontinence surgery in the elderly population. In a subanalysis of the Stress Incontinence Surgical Treatment Efficacy (SISTEr) trial, Richter et al³⁹ found that women age 65 years and older undergoing colposuspension and autologous rectus fascia sling procedure have similar perioperative courses to women under 65 years of age. Older women were significantly more likely to have a positive stress test at follow-up, less subjective improvement in SUI and UUI, and were more likely to have undergone surgical retreatment of SUI by 2-year follow-up. Sharp et al⁴⁰ recently published a review of eight studies comparing outcomes and complications of anti-incontinence surgery in older women (≥ 65 yr) and younger counterparts. Colposuspension and cadaveric fascia were each employed in one study, while the tension-free vaginal tape (TVT™; Gynecare, Ethicon, Somerville, NJ) was used in six studies. While follow-up periods and definitions of success differed between studies, anti-incontinence surgery in older women appeared to be relatively safe and effective. However, older women often did not achieve similar surgical outcomes as younger women, and there was an increase in age-related morbidities. Elderly women undergoing TVT have been prospectively compared to women waiting for surgery, and the QoL indices and patient satisfaction were significantly higher in the surgery group.⁴¹ Additionally, the ability to perform the TVT under intravenous and local anesthesia may be especially useful in the elderly population.⁴²

Overall, complications after sling procedures in Medicare beneficiaries appear to be more common than in the general population, and increase with age.^43,44 Of the 1356 sling procedures performed between January 1, 1999, and July 31, 2000, 12.5% of women developed a urologic complication within 3 months of the procedure, and 33% were diagnosed with a UTI.⁴³ Within 1 year of the surgery, 6.9% of women had a new diagnosis of outlet obstruction, and 8.0% underwent treatments to manage outlet obstruction. Likewise, there was a high incidence of new diagnoses of UUI (15.2%) and treatment of pelvic prolapse (23.2%), and the incidence of cystoscopy and urodynamics in the postoperative period was also high (32.4% and 30.5%, respectively), serving as a potential indicator of complications. When bivariate analyses of the data were stratified by age, Medicare beneficiaries age 75 years and older had more complications.⁴⁴ At 1 year after surgery, women age 65-74 years had significantly less urge incontinence, treatment failure, and outlet obstruction than women age 75 and older. Older women also had a higher incidence of nonurologic adverse events, such as pulmonary embolism and cardiac events. However, this information should be interpreted carefully. The majority of these women likely underwent a traditional bladder neck sling, which has been viewed historically as a procedure with significant morbidity. The cohort in these reviews may not be very contemporary, as the midurethral slings were not widely employed at the time of data collection.

Conclusions

A significant number of women will have urinary incontinence as they age, whether it is SUI, UUI, or MUI. The elderly woman may be uniquely susceptible to the development, or worsening, of incontinence due to hypoestrogenism, decrease in urethral striated musculature, and the development of urodynamic detrusor hyperactivity. Additionally, the elderly may be prone to incontinence due to the adverse effects of common comorbid conditions, such as diabetes and congestive heart failure. Impaired mobility and increased nocturnal urine production are additional contributing factors. Furthermore, many common medications used to combat hypertension, depression, and Alzheimer’s disease may have adverse side effects that worsen incontinence.

While elderly women may be presented with the same options for treatment of urinary incontinence as their younger counterparts, several factors must be considered. First, antimuscarinic medications for treatment of UUI have different side-effect profiles, and some drugs in this class may have a greater capacity for inducing neurologic dysfunction. Second, surgical options for SUI appear to provide symptom relief in the elderly, although the outcomes may not be as good as those seen in younger women. Third, the elderly appear to have a greater incidence of postoperative urologic complications, such as de novo storage symptoms, obstructive phenomena, and urinary tract infections. There is also an increased incidence of nonurologic complications, likely related to preexisting comorbidities in the elderly. These surgical outcomes should be interpreted carefully as the definitions of success, as well as definitions of “elderly,” vary greatly by study. As there is a dearth of randomized trials involving the elderly, these would be welcome to answer some of the questions about outcomes and complications in this ever-increasing population.

The author reports no relevant financial relationships.

Dr. Gomelsky is Associate Professor of Clinical Urology, Department of Urology, Louisiana State University Health Sciences Center, Shreveport.