Psychometric properties of a self-assessment questionnaire concerning symptoms and impairment in urinary tract infections: the UTI-SIQ-8

Objectives To validate the urinary tract infection-Symptom and Impairment Questionnaire (UTI-SIQ-8), a questionnaire that consists of four items to assess the symptom severity for dysuria, urgency, frequenc, and low abdominal pain and four items to assess the resulting impairment of activity by UTIs. Design Prospective observation study. Setting German primary care practices. Participants An unselected population of women with UTI. Women could participate online via a web application for smartphones, smartwatches and tablets or use a paper-and-pencil version. Main outcomes Psychometric properties of the UTI-SIQ-8 regarding reliability, validity and sensitivity to change by using factor analysis and multilevel and network analysis. Results Data from 120 women with a total of 769 symptom reports across 7 days of measurement were analysed. The majority of the participating patients (87/120) used the web application via smartphones or other devices. The reliability of the UTI-SIQ-8 was high, with Cronbach's alpha of.86 at intake; convergent and discriminant validity was satisfactory. Intraclass correlation demonstrated high sensitivity to change, with 68% of the total variance being due to time differences. These daily changes in an individual's symptoms moved parallel with daily changes in the EQ-5D-5L (b=1.68, SE=0.12, p<0.001) and the visual analogue scale (b=0.03, SE=0.003, p<0.001), also highlighting convergent validity with respect to daily changes in symptom severity. Conclusions The present findings support the UTI-SIQ-8 questionnaire as an economic, reliable and valid instrument for the assessment of symptom severity and symptom change in women with uncomplicated UTI. The web application helped patients to report symptoms on a daily basis. These findings may encourage primary care physicians to use the UTI-SIQ-8 in their daily practice and researchers to apply it to studies involving patients with uncomplicated UTI.