Nocturia in the elderly: A wake-up call
ABSTRACTNocturia is a condition that health providers must seek out and address in older adults. Since it adversely affects quality of life and carries a risk of morbidity and of death (often because of falling), this symptom must be elicited during the physician-patient encounter. Understanding its underlying causes, risk factors, and consequences is essential in formulating the most suitable management strategy. Drug and nondrug treatments target the individual disorders that contribute to nocturia.
KEY POINTS
- Nocturia is multifactorial and is caused by factors that increase urine production and others that decrease the bladder’s ability to hold urine.
- The first priority in treating nocturia is to identify and treat concomitant conditions that may be contributing to it, such as diabetes mellitus, diabetes insipidus, urinary tract infections, hypercalcemia, and hypokalemia.
- Nonpharmacologic measures can help, but by themselves usually do not solve the problem.
- Drug therapies for nocturia include desmopressin (DDAVP), antimuscarinic agents, alpha-blockers, and 5-alpha reductase inhibitors.
WHICH PATIENTS ARE AT RISK?
Obesity is associated with a higher incidence of moderate to severe nocturia.15 Studies have shown that the higher the body mass index, the greater the number of nighttime voids, especially in women.16
Habitually eating at night, with poor daytime appetite, is shown to be associated with increased nighttime diuresis.
Obstructive sleep apnea17 and untreated depressive symptoms such as frequent napping18 are also associated with moderate to severe nocturia.19
Higher systolic blood pressures are associated with more urine production at night. Plasma ADH regulation is also altered, which contributes to nocturnal polyuria.21
Other comorbid conditions associated with nocturia include recurrent cystitis, lung disease, congestive heart failure, neurodegenerative conditions (eg, Alzheimer disease and parkinsonism), and chronic kidney disease.21
Drugs associated with nocturia include cholinesterase inhibitors (for dementia),22 beta-blockers,23 and calcium channel blockers.24
Lifestyle factors. Alcohol and coffee have shown either no or only a mild diuretic effect. Smoking has not been shown to be associated with nocturia.15
Seasonal differences also exist, with increased frequency of nocturia in the winter.25
WHAT ARE THE CLINICAL CONSEQUENCES OF NOCTURIA?
Quality of life can be profoundly affected, and if nocturia is left untreated, it may lead to morbidity and even death. Elderly patients may feel simultaneously debilitated, frustrated, distressed, and puzzled. Nocturia may also increase their fear of falling and may negatively affect personal relationships.26
Falls, injuries. Nocturia exposes elderly patients to injuries such as hip fractures due to falling, significantly increasing the incidence of this injury.26 This occurs as elderly patients get up from bed and walk to the bathroom to void.27 In addition, during the day, superficial and fragmented sleep leads to daytime sleepiness and impaired perception and balance, also increasing the risk of falls.28 The complications of immobility and the need for surgery in many cases lead to debility, increased risk of infections, decubitus ulcers, and death. The risk of hip fractures can lead elderly patients with nocturia to associate this symptom with a fear of falling and can alter their concept of their own age (“Nocturia makes me feel old”),29 further diminishing quality of life.
The estimated medical cost of nocturia-associated falls in the elderly is about $1.5 billion per year, part of the $61 billion in lost productivity due to nocturia in adults.30
Long-term complications (eg, debilitation, poor sleep, obesity, decreased energy), increase the overall mortality rate, especially in patients who report voiding more than three times per night.29 Elderly patients with nocturia also have a greater need for emergency care.31
Nocturia also complicates other comorbid conditions, such as dementia, which increases the risk of urinary incontinence.32 In patients who have had a stroke, nocturia is the most frequent lower urinary tract symptom, and represents a major impact on daily life.33
Sleep disturbance is another important consequence. In one survey,34 nocturia was cited as a cause of poor sleep four times more often than the cause cited next most often, ie, pain. Because the elderly patient is awakened from sleep numerous times throughout the night, nocturia leads to more fatigue,35 lower energy levels, and poorer quality of sleep.36 Depression may be linked to poor sleep, as men with two or more nocturnal episodes were shown to be six times more likely to experience depression.
The patient is not the only person who loses sleep: so do the patient’s family members or sleeping partner.7 It is therefore not surprising that sleep disruption caused by nocturia has been cited as a principal reason for admitting older relatives to care homes.37
The risk of death is higher for elderly patients with coronary heart disease if they have nocturia. The causative link is the hemodynamic changes (increases in blood pressure and heart rate) that accompany awakening and arising, which may cause cardiovascular strain and lead to cardiovascular events. The 12-year survival rate has been shown to be significantly lower in patients with nighttime voiding, making nocturia a highly significant independent predictor of death in coronary heart disease patients.38
HOW TO EVALUATE AN OLDER ADULT WHO PRESENTS WITH NOCTURIA
A thorough history and physical examination are crucial in diagnosing nocturia. The goal is to identify any treatable underlying condition, such as diabetes mellitus, obstructive sleep apnea, diabetes insipidus, overactive bladder, benign prostatic hyperplasia, urinary tract infection, and congestive heart failure. Laboratory tests and imaging studies can help rule out these underlying conditions.
Other important facets in the history that must be elicited are medication use, patterns of fluid intake, and a history of other urinary complaints.39
A voiding diary and indices of nocturia
A voiding diary is extremely useful and should be used whenever possible. Episodes of incontinence, time of voids, volume voided, and frequency and volume of fluid intake are recorded. From the raw data, one can determine the following:
Total nocturnal urine volume, ie, the sum volume of the nighttime voids
Maximum voided volume, ie, the largest single recorded volume voided in a 24-hour period
Nocturia index, ie, the total nocturnal urine volume divided by the maximum voided volume. A nocturia index greater than 1 shows that nocturnal urine production is greater than the functional bladder capacity. Clinically significant nocturia is observed in patients with a nocturia index of 2.1 or greater.
Nocturnal polyuria index, ie, total nocturnal urine volume divided by the 24-hour urine output. A nocturnal polyuria index higher than 33% implies nocturnal polyuria.40
Nocturnal bladder capacity index, ie, the actual number of nightly voids minus the predicted number of nightly voids, which in turn is calculated as the nocturia index minus 1.
It is especially important to encourage patients to make a voiding diary, as some patients may find this cumbersome, and compliance can be low unless its importance is emphasized. A diary over 7 days usually gives meaningful data. The results from the diary typically confirm the presence of nocturnal polyuria or a decrease in bladder capacity, influencing management.41
