Nocturnal polyuria can't be diagnosed using a standard history alone, researchers say.
"You should do a 24-hour voiding diary in addition to medication history and examination in order to diagnose polyuria," Jeffrey P. Weiss, MD, of State University (SUNY) Downstate in Brooklyn, NY, told Urology Times.The study was presented by Harjot Singh of SUNY Downstate at the AUA annual meeting in San Francisco.
Nocturnal polyuria as a cause of nocturia may affect a person's quality of life and lead to increased falls and even death. The International Continence Society defines nocturnal polyuria as urine volume in excess of 33% of 24-hour urine volume in people over 65 years of age. Alternatively, Bosch et al have proposed defining nocturnal polyuria as more than 90 mL/hr of urine production without reference to 24-hour output.
To measure the importance of previously identified risk factors for nocturnal polyuria, Dr. Weiss, Singh, and their colleagues retrospectively analyzed data on 524 patients who had completed a 24-hour flow volume chart during an evaluation of lower urinary tract symptoms.
They extracted data on past medical history, surgical history, and eight groups of medications: alpha-blockers, diuretics, angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, muscarinic antagonists, beta blockers, 5-alpha-reductase inhibitors, and phosphodiesterase-type-5 inhibitors.
They measured rates of overactive bladder, BPH, urethral stricture, urinary incontinence, hypertension, hypothryroidism, diabetes, urethral obstruction, prostate cancer, pedal edema, neurogenic bladder, Parkinson's disease, and sleep apnea.
In this population, some risk factors were overrepresented compared to the general population, including OAB and BPH, while others were underrepresented, including urinary incontinence, urethral obstruction, prostate cancer, and hypertension.
They divided the patients into two groups: 145 (96 male and 49 female) with nocturnal polyuria, defined as greater than 0.33 on the Nocturnal Polyuria Index, and 379 (242 male and 137 female) with normal urine production, defined as less than 0.33.
The authors found no statistically significant differences in risk factors between the two groups. They were particularly surprised to find that established risk factors such as sleep apnea and pedal edema did not correlate to nocturnal polyuria, they said. They speculated that this was due to the small sample size.