PHILADELPHIA—An expert panel has developed a phenotype classification system for nocturia that could provide a basis for devising diagnostic and treatment pathways for the condition, according to a presentation at the International Continence Society’s 2018 annual meeting.
The system is based on findings from a retrospective multicenter study that included 331 patients (197 men and 134 women) evaluated for lower urinary tract symptoms (LUTS).The investigators included in their analysis 295 patients who had completed a 24-hour bladder diary (24HBD), a LUTS score questionnaire, and uroflow and post-void residual (PVR) urine evaluations.
Based on the findings, a team led by Jerry G. Blaivas, MD, of the Icahn School of Medicine at Mount Sinai and Institute for Bladder and Prostate Research in New York, constructed a conceptual framework consisting of 5 major nocturia phenotypes: polyuria, nocturnal polyuria, small bladder capacity, mismatches, and sleep disorders. The authors defined nocturia as 1 or more nighttime voids recorded in the 24-hour HBD.
Dr Blaivas and his collaborators subdivided each major phenotype based on maximum voided volume (MVV), uroflow, and PVR findings. The reference value for polyuria was a 24-hour volume greater than 2.5 L. For nocturnal polyuria, the reference value was a nocturnal polyuria index of 0.33. The reference value for small bladder capacity was an MMV less than 150 mL. For mismatches, the reference values were 1 or more nighttime voids, nocturnal polyuria index 0.33 or less, and MVV 150 mL or greater. The reference value for sleep disorders was 1 or more insomnia voids.
The reference value for sleep disorders was 1 or more insomnia voids. Uroflow and PVR findings were divided into normal or abnormal. In the end, the panel devised a conceptual framework consisting of 24 phenotypes.
“At first glance, 24 phenotypes may seem a bit daunting, but we believe that this is only the first step towards precision medicine for patients with nocturia,” Dr Blaivas told Renal & Urology News. “We are in the process of developing a clinical care pathway for nocturia that utilizes these phenotypes. We call that ‘a bottom-up approach,’ in contradistinction to the ‘top-down, one size fits all’ approach taken by most guideline committees.”
Meeting Chairman Alan J. Wein, MD, PhD (hon), Founders Professor and Emeritus Chief of Urology at the University of Pennsylvania’s Perelman School of Medicine in Philadelphia, commented that the effort by Dr Blaivas and colleagues “portrays an interesting intellectual exercise, which is clever and attempts to categorize nocturia patients presumably for selection into groups for different types of management.”
Still, the large number of categories in the proposed phenotypic classification scheme makes it too complicated to be of practical use in routine clinical practice, he pointed out. “Nocturia is an important standalone problem, but it’s not rocket science for the person who wants to manage it.”
Clinicians just have to remember a few basic principles about what could be causing nocturia, and then determine patients’ most bothersome symptom or symptom complex. They should manage that first, starting with “simple hits up front,” such as behavior modification, and then progress to specific pharmacologic management, Dr Wein said.
Blaivas J, Kreder K, Chaikin D, et al. Development of nocturia phenotypes. Data presented at the International Continence Society 2018 annual meeting in Philadelphia, August 28–31. Abstract 14.