Aim and objectives: The aim of this study was to extend the scope of application of the Incontinence Impact Questionnaire-7 (IIQ-7) with the objective of assessing the applicability, validity, reliability and sensitivity of the IIQ-7 in both Chinese males and females with lower urinary tract symptoms (LUTS).
Methods: The validity, reliability and sensitivity were assessed in 233 patients who were recruited in Hong Kong primary-care settings. The internal construct validity was assessed by corrected item-total correlation. The convergent validity was assessed using Pearson's correlation test against International Prostate Symptom Score (IPSS) quality-of-life question and Short Form 12, version 2 (SF-12v2). The reliability was assessed by the internal consistency (Cronbach's alpha coefficient) and 2-week test-retest reliability (intraclass correlation coefficient and paired t test). The sensitivity was determined by performing known group comparisons by independent t test.
Results: Corrected item-total correlations were ≥0.4 for all items in males and females. Overall, the IIQ-7 total score had a stronger correlation with IPSS quality-of-life score than the SF-12v2. The IIQ-7 showed good internal consistency (Cronbach's alpha coefficient >0.7) and good test-retest reliability (ICC > 0.8, paired t test p value >0.05). The IIQ-7 was more sensitive than the SF-12v2 to detect differences among patients with different levels of symptom severity.
Conclusions: The IIQ-7 Chinese version appears to be a valid and reliable measure to assess Cantonese-speaking males and females with LUTS. The IIQ-7 is more sensitive than generic health-related quality-of-life measures to detect differences between groups.