Comparison of Two Questionnaires for Assessing the Severity of Urinary Incontinence: The ICIQ-UI SF Versus the Incontinence Severity Index

Aims: To compare the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form (ICIQ-UI SF) with the Incontinence Severity Index (ISI), and to propose intervals for four severity levels of ICIQ-UI SF. Methods: Cross-sectional, Internet-based study of 1,812 women responding to a general health questionnaire. Four severity levels for the ICIQ-UI SF scores were constructed by iteratively adjusting the ranges for these levels until maximum Kappa scores were obtained when cross-tabulated with the ISI in a random sample of half of the women with urinary incontinence. Using these intervals, weighted Kappa was calculated for the remaining women as a validation process. Results: Three hundred forty-three women had urinary incontinence, and completed the ISI and the ICIQ-UI SF. A high correlation between the ISI and ICIQ-UI SF scores with versus without the QoL item was found (Spearman's rho = 0.62, P < 0.01 vs. rho = 0.71, P < 0.01, respectively). Maximum Kappa with quadratic weighting was obtained for the following scale for the ICIQ-UI SF: slight (1-5), moderate (6-12), severe (13-18) and very severe (19-21) (Kappa = 0.61), and without the QoL item: slight (1-3), moderate (4-5), severe (6-9) and very severe (10-11) (Kappa = 0.71) in the development sample. Correspondingly, for the validating sample, maximum Kappa with quadratic weighting was 0.61 and 0.74. Conclusions: A high correlation between the ICIQ-UI SF and the ISI was found. The ICIQ-UI SF may be divided into the following four severity categories: slight (1-5), moderate (6-12), severe (13-18) and very severe (19-21). Neurourol. Urodynam. 28:411-415, 2009. (C) 2009 Wiley-Liss, Inc.