Health utility value of overactive bladder in Japanese older adults

Abstract

Objectives: To determine the health utility values (HUVs) of overactive bladder (OAB), defined as urinary urgency, usually accompanied by urinary daytime or nocturnal frequency, with or without urinary incontinence, among adults aged ≥65 years and to assess the HUV decrements (disutilities) of OAB according to its severity.

Methods: This cross-sectional Internet-based study was conducted between 2 and 9 November 2023, with quota sampling with equal probability for each sex and age group (age 65-74 years and ≥75 years). OAB was defined as an urgency score of ≥2 points and a total score of ≥3 points based on the Overactive Bladder Symptom Score. OAB severity was categorized as mild (total score, ≤5 points) or moderate-to-severe (total score, 6-15 points). HUVs were measured using the EuroQol five-dimension five-level value set for the Japanese population. Multivariable linear regression models were fitted to estimate the covariate-adjusted disutilities of OAB. We selected eight covariates (age, sex, body mass index, education, income, smoking, alcohol use, and comorbidities) as potential confounders based on previous studies. The sample size was determined based on previous studies without statistical power calculations.

Results: Among the 998 participants (51.9% male; mean age, 73.2 years), 158 (15.9%) had OAB, of whom 87 (8.8%) had moderate-to-severe OAB. The mean HUVs for participants with mild and moderate-to-severe OAB were 0.874 and 0.840, respectively, which were lower compared with the HUV for those without OAB (0.913). After adjusting for relevant covariates, disutilities (95% confidence intervals [CIs] and p values) for mild and moderate-to-severe OAB were -0.0334 (-0.0602 to -0.0066, p = 0.014) and -0.0591 (-0.0844 to -0.0339, p < 0.001), respectively.

Conclusions: Consistent with previous HUV studies on OAB, our results demonstrated that the prevalence of OAB was associated with substantially lower HUV. The results demonstrate that increased OAB severity is associated with greater disutility.

Keywords: health economic evaluation; health utility; health‐related quality of life; lower urinary tract symptoms; overactive bladder.

FIGURE 1

Flow diagram of this study.

FIGURE 2

Results of multivariable linear regression models in the subgroup analyses. *Adjusted for age, sex, body mass index, educational attainment, equivalent household income, smoking status, alcohol consumption, and presence of comorbidities (hypertension, dyslipidaemia, diabetes, low back pain, ischaemic heart disease, stroke, chronic kidney disease, stress urinary incontinence, depression, and other psychiatric disorders). Abbreviations: CI, confidence interval; OAB, overactive bladder.

FIGURE 3

Results of multivariable linear regression models in the exploratory analyses. *Adjusted for age, sex, body mass index, educational attainment, equivalent household income, smoking status, alcohol consumption, and presence of comorbidities (hypertension, dyslipidaemia, diabetes, low back pain, ischaemic heart disease, stroke, chronic kidney disease, stress urinary incontinence, depression, and other psychiatric disorders). Abbreviations: CI, confidence interval; OABSS, overactive bladder symptom score.