Nocturnal polyuria in women: results from the EpiNP study

Introduction and hypothesis Data from a large US population-based, cross-sectional, epidemiological study (the EpiNP Study) were used to assess the symptoms and bother experienced by women with nocturnal polyuria (NP). Methods Consenting participants recruited from an online panel completed the baseline EpiNP survey online (Lower Urinary Tract Symptoms Tool and urological comorbidities). All reporting ≥2 voids/night and a random sample of 100 respondents, each reporting 0 or 1 void/night were asked to complete a 3-day web-based bladder diary recording time, volume, and urgency rating of each void. NP was calculated by the proportion of urine production that occurred during nocturnal hours using a Nocturnal Polyuria Index (NPI33) threshold of >0.33 or nocturnal urine production of >90 ml/h (NUP90). The frequency of participants reporting LUTS and bother was determined by age and NP: idiopathic NP, NP associated with overactive bladder (NPOAB), NP associated with comorbidities (NPCom), and no NP (did not meet NP criteria). Results A total of 5,290 women completed the baseline survey. Mean age (range) was 54.9 (30–95) years; 1,841 (34.8%) reported ≥2 nocturnal voids. The prevalence of LUTS increased across the lifespan; however, bother associated with each LUTS decreased with increasing age. The percentage of women rating bother by nocturia episodes ≥2 “> somewhat” ranged from 40.3% to 68.3%, with bother ratings highest in the NPOAB and No NP groups. Conclusions NP is prevalent in women with considerable bother and is often associated with other urinary symptoms. Multifactorial causes and potential treatments of NP should be considered, particularly at a later age.