Construct validity of a questionnaire to measure the type of fluid intake and type of urinary incontinence.

ABSTRACT

OBJECTIVE: To determine the reproducibility and construct validity of the Questionnaire Based Voiding Diary (QVD) for measuring the type and volume of fluid intake and the type of urinary incontinence. METHODS: 250 women completed the QVD, a 48-hour bladder diary and underwent complete urogynecologic evaluation to determine a final clinical diagnosis. The questionnaire was re-administered after a 2-week period with no change in treatment, and 2-3 months later following treatment of urinary symptoms. RESULTS: The reproducibility of the fluid intake, output, fluid intake behavior and urinary symptom subscales of the QVD was 0.68-0.92. Correlation of the fluid intake scale of the QVD with the 48-hour voiding diary for determining the type and volume of fluid intake was high (r = 0.65-0.83, P < 0.01). High correlations were noted between the fluid intake behavior scale and urinary frequency (r = 0.82, P < .01), urgency (r = 0.77, P < .01) and urge incontinence (r = 0.71, P < .01). The median total fluid intake and mean urinary symptom score was significantly lower in responders (2074 mL, 10.2 ± 3.3) than non-responders (2347 mL, 18.5 ± 4.6). As compared to the final clinical diagnosis, the sensitivity, specificity and positive likelihood ratio of the QVD for the diagnosis of predominant stress urinary incontinence are 86%, 66% and 2.6 and for predominant urge incontinence 82%, 79% and 4.0 respectively. CONCLUSION: The QVD provides clinically meaningful information on the type and volume of fluid intake and the type of urinary incontinence at the initial office visit.