The definition of nocturia has been as nebulous as its etiology and management. In 2002, the International Continence Society defined nocturia as waking up at night at least once to void (Neurourol Urodyn 2002; 21:179-83). However, clinically relevant nocturia is generally accepted among urologists to indicate two or more voids that are preceded and followed by sleep. It is worthy to note that neither definition accounts for the patient’s degree of bother from nocturia, though waking twice or more from sleep to void has been associated with impaired quality of life (Eur Urol 2010; 57:488-98).
The economic burden of nocturia is substantial and includes injuries from falls, lost work productivity, and intangible losses such as distress, behavior changes, and confinements. The estimated financial impact is considerable, as indirect costs have been estimated at $61 billion per annum (Neurourol Urodyn 2014; 33 [suppl 1]:S10-4).
In this article, we review the underlying causes of nocturia and outline an approach to its diagnostic evaluation and treatment.
Nocturia is a gender-neutral entity with multifactorial underlying causes. While many studies have investigated the epidemiology of nocturia, the lack of standardized terminology has obscured research results. In a large population-based study, Tikkinen et al concluded that nocturia is more common in women under age 50, has about the same prevalence among men and women ages 50-59, is more frequent in men above age 60, and increases in prevalence more rapidly with age in men than it does in women (J Urol 2006; 175:596-600).
McVary et al found that most men with LUTS identify their chief LUTS complaint as nocturia and that, importantly, this symptom persists without improvement in nearly half of men (Urology 2015; 86:862-7). Echoing this unmet need in LUTS, the AUA guidelines for non-neurogenic overactive bladder (OAB) note that most of the reviewed studies included robust data on urinary frequency and incontinence, but “only a handful reported nocturia data” (J Urol 2015; 193:1572-80).