Introduction Nocturia Is a Frequently Described Symptom That May Be Associated with a Variety of Disorders

NOCTURIA IS A FREQUENTLY DESCRIBED SYMPTOM THAT MAY BE ASSOCIATED WITH A VARIETY OF DISORDERS INCLUDING OBSTRUCTIVE SLEEP APNEA-HYPOPNEA SYNDROME (OSAHS).1-4 The consequences of nocturia are significant, especially in the elderly in whom urination three times per night has been associated with sleep disruption, daytime fatigue and an increased number of falls.5-7 Urinating two or three times per night is associated with an approximately two-fold increase in the risk for falls, although it is not specifically reported whether the falls occur while the patients are getting up to urinate.6 A main reason for institutionalization of family members are sleep problems (in 70% of all cases) and nocturia is the specific sleep problem in 60% of instances.8 The reported prevalence of nocturia in the general population varies across studies. In part, this may be related to the absence of a uniform definition of the condition and differences in the nature of the study populations. Defining nocturia as at least one urination episode per night, the reported prevalence is 64%-80% in elderly individuals (9-12) and 56% among men older than 45 years (13). Defining nocturia as two or more urination episodes per night, the prevalence is 24%-55% in the elderly.5,9,11,14-16 The mechanism by which OSAHS leads to pathologic nocturia (PN) has not been definitively identified. OSAHS leads to disturbed sleep, which itself may be associated with nocturia. Pressman reported that 76% of nocturnal urination episodes were immediately preceded by an episode of obstructive apnea or snoring and 3% by periodic limb movement.17 Although the prevalence of nocturia specifically in patients with OSAHS has not been extensively studied, the frequency of nocturia has been reported to be greater in adult men with OSAHS than in age controlled healthy male adults and also has been positively correlated with the severity of OSAHS. The average frequency of nocturnal urination episodes was 2.2/week in normal individuals, 2.6/week in patients with mild to moderate OSAHS (AHI<50/hr), and 3.9/week in patients with severe OSAHS (AHI>50/hr).18 In one epidemiological study, nocturia was found to be related to diuretic use, cardiovascular disease, diabetes mellitus, and alcohol consumption among males without prostatic enlargement.12 However, the presence of sleep apnea was not assessed in this investigation. On the other hand, a significant association between episodes of nocturia and symptoms of OSAHS was reported in African-American women.19 The objective of the current investigation was to determine the prevalence of nocturia among adults with OSAHS and to identify factors that may be predictive in this regard. Such information may have implications for OSAHS case-finding and severity prediction.