The Recurrent Urinary Tract Infection Symptom Scale: Development and validation of a patient-reported outcome measure.

Objectives: This study aimed to develop and validate a tailored patient-reported outcome measure (PROM) evaluating the patient experience of recurrent urinary tract infection (rUTI) symptom severity. This measure was designed to supplement clinical testing methods, allowing full assessment of the patient experience of rUTI symptom burden, while enhancing patient-centred UTI management and monitoring. Subjects and Methods: The Recurrent Urinary Tract Infection Symptom Scale (RUTISS) was developed and validated using a three-stage methodology, in accordance with gold-standard recommendations. Firstly, a two-round Delphi study was conducted to gain insights from 15 international expert clinicians working in rUTI, developing an initial pool of novel questionnaire items, assessing content validity and making item refinements. Next, two phases of one-to-one semi-structured cognitive interviews were conducted with a diverse sample of 28 people experiencing rUTI to assess questionnaire comprehensiveness and comprehensibility, making refinements after each phase. Finally, a comprehensive pilot of the RUTISS was conducted with 240 people experiencing rUTI across 24 countries, providing data for psychometric testing and item reduction. Results: Exploratory factor analysis indicated a four-factor structure comprising: 'urinary pain and discomfort', 'urinary urgency', 'bodily sensations' and 'urinary presentation', together accounting for 75.4% of the total variance in data. Qualitative feedback from expert clinicians and patients indicated strong content validity for items, which was supported by high content validity indices in the Delphi study (I-CVI > 0.75). Internal consistency and test-retest reliability of the RUTISS subscales were excellent (Cronbach's α = 0.87-0.94 and ICC = 0.73-0.82, respectively), and construct validity was strong (Spearman's ρ = 0.60-0.82). Conclusion: The RUTISS is a 28-item questionnaire with excellent reliability and validity, which dynamically assesses patient-reported rUTI symptoms and pain. This new PROM offers a unique opportunity to critically inform and strategically enhance the quality of rUTI management, patient-clinician interactions, and shared-decision making by monitoring key patient-reported outcomes.