Revisiting the UDI and IIQ: proposed more stable models

Assessing and reviewing a person’s incontinence status is an essential task for nurses. Two clinically-useful and widely used scales which measure the symptoms and impact of incontinence are the Urogenital Distress Inventory (UDI) and Incontinence Impact Questionnaire (IIQ). Short forms, more amenable for use in nursing assessments, have been derived from sub-scales contained within the long forms. The aim of the research was to assess the suitability of the Urogenital Distress Inventory (UDI) and Incontinence Impact Questionnaire (IIQ) sub-scales and their short forms for use with a Scottish population. Study participants were 237 females with urinary incontinence from two Scottish regions. Principal Components Analysis, Best Subset Regression, Structural Equation Modelling and Cronbach’s alpha were used to assess reliability and stability. New scales and sub-scales were generated and tested for goodness-of-fit on the Scottish data. Stability was assessed using test-retest data from the same population. The same structure of sub-scales previously reported did not emerge, although some overlap was apparent. Different short forms also emerged. Using more flexible modelling methods, sub-scales with greater stability were developed for the UDI and IIQ. The resulting 11-item UDI and 11-item IIQ models had good internal consistency. Cronbach’s alpha was 0.829 and 0.898 respectively. The researchers conclude that internationally robust yet practical measures of incontinence are needed in nursing. Previous reports on the UDI and IIQ sub-scales and short forms and their associated psychometric properties may not be relevant to populations different to those in which the instruments were developed. Further retrospective and prospective assessment is recommended.