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Evaluation of the International Consultation on Incontinence Questionnaire Short-Form : evidence from a surgical population

University of British Columbia

The International Consultation on Incontinence Questionnaire Short-Form (ICIQ-UI-SF) is a four-item patient-reported outcome (PRO) measure. Its intended use is screening for incontinence, assessing impact of incontinence on quality of life, and facilitating patient-clinician discussions. Evaluations of this instrument to date have relied on a simple set of analytical tools—limiting user’s confidence of the instrument’s validity and reliability. The purpose of this thesis was to conduct a comprehensive evaluation of the ICIQ-UI-SF. The analyses were conducted on 177 completed ICIQ-UI-SF instruments by men with chronic urinary incontinence waitlisted for urological surgery for treatment of their condition. This comprehensive evaluation included application of the following methods: confirmatory factor analysis (CFA), principal component analysis, measures of reliability (classical test theory (CTT) and McDonald’s coefficient), item response theory (IRT), and differential item functioning (DIF). A supplemental investigation examined previously constructed ICIQ-UI-SF severity categories. Specific goals included assessing: instrument characteristics (dimensionality, ceiling effects), reliability, performance of individual items, whether socioeconomic status influences patients’ ICIQ-UI-SF scores, and concordance with other commonly collected PROs (EQ-5D-3L, Visual Analogue Scale). Responses to all items were left skewed and ceiling effects were identified. Model fit could not be assessed through the CFA, however the factor loadings of items one and two differed significantly (p < 0.0002) from item three indicating possible multidimensionality. The PCA contrastingly provided some, albeit limited evidence that the ICIQ-UI-SF is unidimensional. Reliability was low/moderate as measured by Cronbach’s alpha (0.63) and McDonald’s coefficient (0.65). The IRT revealed the third item’s reliability may be improved by collapsing response levels. The instrument does not discriminate between individuals with high incontinence burden. There was no DIF by socioeconomic status. Supplemental investigations demonstrated the ICIQ-UI-SF discriminates between surgical patients with mild/moderate incontinence versus severe/very severe—but not beyond these dichotomies. Directly comparing ICIQ-UI-SF scores of urological surgery patients with high incontinence burden is not recommended. If unchanged, the ICIQ-UI-SF can be used as a complement to other data, such as reporting aggregated surgical outcomes, or as a starting point for patient-clinician discussions when applied to a surgical population. For application to surgical triage, this analysis recommends amendments to the ICIQ-UI-SF.

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2017-11-20

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/63667

Population and Public Health

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/