Nocturia, generally described as waking up at night to void, is one of several lower urinary tract symptoms (LUTS) that are frequently present and often bothersome to women. However, there is no standardization of what defines nocturia in women. Various definitions have been provided in the literature, but none account for bothersomeness of the nocturia. Some women find voiding at night not to be a large problem, while others state it does affect their quality of life. The number of nighttime voids that defines clinically significant nocturia has yet to be established and severity of nocturia has not been categorized based on degree of bother to the patient. Dr. Joshua Fiske and colleagues at the New York University School of Medicine study this problem and report their findings in Neurourology and Urodynamics in March, 2004. The authors set out to determine whether the frequency of nocturia correlates with the degree of bother and to determine if this correlation was affected by age or continence status.

They used the American Urological Association Symptom Index (AUASI), which has been shown to correlate LUTS with degree of bother in women, to establish this correlation. They attempted to establish criteria for defining clinically significant mild, moderate, and severe nocturia, based on degree of bother. To do this they reviewed the charts of 1,500 consecutive women presenting to a female urology practice during a three-year period. A total of 1,232 women met inclusion criteria by answering the AUASI and the Symptom Problem Index (SPI). The mean age of patients was 54.6 years. One thousand and sixty women (87.3%) reported waking at least one time per night to void and 728 women (60%) reported voiding at least two times per night. The mean age of these women was 55.2 and 57.2 years, respectively.

The patients' bother score increased as the number of nightly voids increased. A proportional odds model showed that as the number of voids increased one value on the AUASI, the odds of having an increase in bother increased 2.7 times (P-value<0.0001). When patients' age and continence status were included as effect modifiers in the proportional odds model, they did not have a significant impact on the association between the degree of bother and the number of nighttime voids. The degree of bother was further classified as non-problematic or problematic, according to the SPI. 74.2% of women stated that voiding 0 to 1 times per night was non-problematic, and 25.8% of these women stated that this voiding pattern was problematic. Conversely, only 22.7% of women who voided two or more times stated that this was non-problematic and 77.3% stated that this was problematic. As the number of voids increased to 2 or more times compared to 0 or 1 voids per night, the increase in degree of bother was statistically significant.

Nocturia can significantly impact quality of life by causing sleep deprivation and chronic fatigue. This study suggests a minimum of 2 episodes of nocturia was associated with significant bother in most women and based upon this 2 or more episodes of nocturia per night should be considered clinically significant when one obtains this history from female patients.

Neurourol Urodynam 2004; 23: 130-133