Measuring quality of life in patients with stress urinary incontinence: is the ICIQ-UI-SF adequate?

Abstract

Purpose: The International Consultation on Incontinence Questionnaire Short Form (ICIQ-UI-SF) is a widely used four-item patient-reported outcome (PRO) measure. Evaluations of this instrument are limited, restraining user's confidence in the instrument. This study conducts a comprehensive evaluation of the ICIQ-UI-SF on a sample of urological surgery patients in Canada.

Methods: One hundred and seventy-seven surgical patients with stress urinary incontinence completed the ICIQ-UI-SF pre-operatively. Methods drawing from confirmatory factor analysis (CFA), measures of reliability, item response theory (IRT), and differential item functioning were applied. Ceiling effects were examined.

Results: Ceiling effects were identified. In the CFA, the factor loadings of items one and two differed significantly (p < 0.001) from item three indicating possible multidimensionality. The first two items reflect symptom severity not quality of life. Reliability was moderate as measured by Cronbach's alpha (0.63) and McDonald's coefficient (0.65). The IRT found the instrument does not discriminate between individuals with low incontinence-related quality of life.

Conclusions: Due to low/moderate reliability, the ICIQ-UI-SF can be used as a complement to other data or used to report aggregated surgical outcomes among surgical patients. If the primary objective is to measure quality of life, other PROs should be considered.

Keywords: Ceiling effects; Confirmatory factor analysis; ICIQ-UI-SF; Item response theory; Patient-reported outcomes; Urinary incontinence.