To clarify the characteristics of co-existent overactive and underactive bladder (COUB) in participants with nocturia from the 2023 Japan Community Health Survey.
Participants reporting nocturia (≥1 episode per night) were divided into four groups: COUB, overactive bladder (OAB) alone, underactive bladder (UAB) alone, and neither OAB nor UAB (non-OAB/UAB). Nocturia-related variables were compared across groups. Multivariable analyses were performed to identify predictors of clinical nocturia (nocturia ≥ 2) and factors associated with reporting nocturia as the most impactful symptom in daily life.
Among 2,006 men and 1,787 women with nocturia, the prevalence of COUB was 6.1% and 2.6%, respectively. The proportion of nocturia ≥2 increased significantly in ascending order across four groups in men (non-OAB/UAB, UAB alone, OAB alone, COUB) and women (non-OAB/UAB, OAB alone, UAB alone, COUB) (p < 0.001 for both). Subjective nighttime voided volume (VV) compared to daytime VV and nocturnal voiding trigger also showed significant differences among the four groups in both genders (all p < 0.001). COUB independently predicted nocturia ≥ 2 in men (odds ratio OR: 2.50, p < 0.001) and women (OR: 2.39, p = 0.028). Although nocturia was ranked as the most impactful symptom in all groups, COUB was inversely associated with reporting nocturia as the most impactful symptom (men: OR: 0.43, p = 0.014; women: OR: 0.18, p = 0.002).
COUB represents a distinct and severe phenotype among symptom syndromes and is independently associated with nocturia severity.
Neurourology and urodynamics. 2026 Jun 26 [Epub ahead of print]
Yuka Nagahama, Natsumi Kai, Chihiro Kitagawa, Hironori Hashimoto, Koichi Miyazaki, Shotarou Watanabe, Kurenai Kinno, Yoshitomo Sawada, Yasuharu Takeuchi, Yoshiyuki Kojima, Takahiko Mitsui, Naoya Masumori, Noritoshi Sekido
Department of Urology, Toho University Ohashi Medical Center, Meguro, Tokyo, Japan., Department of Urology, Fukushima Medical University School of Medicine, Fukushima, Fukushima, Japan., Scientific Committee of the Japanese Continence Society, Chiyoda, Tokyo, Japan., Department of Urology, Sapporo Medical University School of Medicine, Sapporo, Hokkaido, Japan.