Development and psychometric validation of a patient-reported outcome measure of recurrent urinary tract infection impact: the Recurrent UTI Impact Questionnaire

Purpose Recurrent urinary tract infection (rUTI) is a highly prevalent condition associated with significant poor quality of life outcomes. A patient-reported outcome measure (PROM) of rUTI-associated psychosocial impact is urgently required to supplement clinical evaluation and validate the challenges experienced by patients. This study therefore developed and validated the Recurrent UTI Impact Questionnaire (RUTIIQ). Methods A rigorous four-stage methodology was followed: (I) concept elicitation through a qualitative survey of the experiences of people with rUTI (N = 1983); (II) Delphi expert screening of the RUTIIQ with expert rUTI clinicians (N = 15); (III) one-to-one cognitive interviews with people experiencing rUTI (N = 28) to evaluate the comprehensiveness and comprehensibility of the RUTIIQ, and (IV) full pilot testing of the RUTIIQ with people experiencing rUTI (N = 240) to perform final item reduction and psychometric analysis. Results Exploratory factor analysis demonstrated a five-factor structure comprising: ‘patient satisfaction’, ‘work and activity interference’, ‘social wellbeing’, ‘personal wellbeing’, and ‘sexual wellbeing’, collectively accounting for 73.8% of the total variance in pilot scores. Results from expert clinicians and patients indicated strong item content validity (I-CVI > .75). The internal consistency and test–retest reliability of the RUTIIQ subscales were excellent (Cronbach’s α = .81–.96, ICC = .66–.91), and construct validity was strong (Spearman’s ρ > .69). Conclusion The RUTIIQ is a 30-item questionnaire with excellent psychometric properties, assessing the patient-reported psychosocial impact of living with rUTI symptoms and pain. This new instrument delivers the unique opportunity to enhance patient-centred care through standardised observation and monitoring of rUTI patient outcomes. Trial registration This study was pre-registered with ClinicalTrials.gov (identifier: NCT05086900). Supplementary Information The online version contains supplementary material available at 10.1007/s11136-023-03348-7.


Introduction
Recurrent urinary tract infection (rUTI), characterised by at least two UTIs in six months or at least three in a year [1], affects over 100 million people annually worldwide and is associated with high UTI-related symptom and personal burden [2][3][4]. Qualitative research has emphasised the breadth of psychosocial challenges faced by people living with rUTI, indicating severe and long-lasting negative consequences for quality of life (QoL) [5][6][7][8][9]. Anxiety and depression are particularly common in this patient population [10], and are exacerbated by the high levels of sexual distress experienced by 60-78% of people with rUTI [11][12][13][14]. The societal implications of UTIs are also significant, with rUTI estimated to cost the NHS an increasing cost of £45 million per year in communitybased prescriptions alone [14][15][16].
Patients regularly report symptoms of UTIs which are not indicated by standard clinical outcome measures [17,18]. Exploring such patient-reported symptoms and associated impacts could offer a unique insight into the rUTI patient perspective and the lived experience of rUTI. Given the distinctive complexities faced by this patient cohort, it is surprising that no validated measure of rUTI impact on QoL currently exists. Generic QoL instruments, including EuroQol assessments such as the 5-item EQ-5D [19], are commonly used in UTI research [20,21].
However, such instruments have not been specifically validated for use with rUTI and are thus not reliably sufficient to capture the rUTI patient experience. Their brief, generalised approach may not meaningfully reflect the spectrum of psychosocial challenges faced by people living with rUTI, and they may be less sensitive to changes in specific aspects of the rUTI experience [22]. Additionally, generic measures such as the EQ-5D do not explore the health-related impact on sexual wellbeing: an important area of impact for many people living with rUTI [8,11,14]. Indeed, recent research emphasises the need for clinicians and researchers to incorporate a condition-specific measure into rUTI care and study designs as standard, in combination with a brief generic measure such as the EQ-5D [22,23].
A comprehensive, condition-specific patient-reported outcome measure (PROM) of rUTI impact on QoL would benefit clinical and research settings, supporting shareddecision making and patient-doctor interactions, highlighting key psychosocial outcomes that require intervention (for example, psychotherapy), and allowing for patient monitoring [22,24,25]. This study therefore aimed to develop and validate the Recurrent UTI Impact Questionnaire (RUTIIQ).

Materials and methods
The RUTIIQ was developed and validated in accordance with PROM development guidelines (see Fig. 1) [26][27][28]. Indepth input from patients and expert clinicians was sought through all research stages [26][27][28], with particular emphasis on patient involvement to ensure the PROM is truly patientcentred [29].

Design, setting, and participants
An online cross-sectional survey of adult females experiencing rUTI (N = 1983, see Table 1 for demographic characteristics) was conducted to collect qualitative data about the impact of living with this condition. Visitors to a website hosted by Live UTI Free (https://liveutifree.com), a UTI patient advocacy and research organisation, were invited to complete the survey. Inclusion criteria comprised a minimum age of 18 years old and meeting the diagnostic criteria for rUTI (≥ 2 UTI in 6 months, or ≥ 3 UTIs in 12 months) based on self-report [1,18]. Informed e-consent was obtained prior to survey completion and participants could withdraw at any point.

Procedure
After providing consent, participants answered questions about their demographic characteristics and clinical history with rUTI, including frequency and duration of symptoms. Next, participants were asked to qualitatively describe their experience of rUTI via an open-text box.

Data handling
Framework analysis of the qualitative data and a thorough literature review were conducted to produce a conceptual framework of rUTI impact (see Online Resource 1 for data handling strategy and see Online Resource 2 for summary of literature consulted) [28,30,31]. After data familiarisation, the first author developed an initial thematic framework of psychosocial components based on factors identified a priori from existing literature and emergent issues raised by participants [31]. The entire research team reviewed this collaboratively in conjunction with the dataset and literature review findings, making agreed revisions. The first author then indexed and annotated the full dataset according to this framework, and patterns were charted and mapped to group the data into defined concepts (see Online Resource 3 for thematic framework) [31]. Secondary coding and triangulation were undertaken by the last author. Both coders hold advanced postgraduate training in research methods and extensive qualitative experience (see Stage III). Disagreements were resolved in discussion with the wider research team and in close consultation with the data. Data saturation was achieved. Each overarching framework component was selected for exploration as a preliminary subscale in the RUTIIQ, and initial items were drafted for each according to the relevant framework subcomponents. Fig. 1 The four-stage methodology employed to develop and validate the Recurrent Urinary Tract Infection Impact Questionnaire (RUTIIQ), a novel patient-reported outcome measure of rUTI impact on quality of life. In-depth input from patient and expert clinician participants was maintained throughout this research, in line with best practice recommendations [26][27][28]

Design, setting, and participants
A Delphi methodology was employed to evaluate the content validity of the initial questionnaire from the perspective of clinicians with rUTI expertise (see Online Resource 4 for all items tested at this stage) [32]. Two rounds of anonymous surveys took place to build towards an expert consensus about the relevance and clarity of the questionnaire items [32].
Thirty-seven expert clinicians were invited to take part (n = 22 female, n = 15 male), of whom 15 were successfully recruited (n = 12 female, n = 3 male), meeting sample size recommendations (see Table 1 for demographic characteristics) [26,32]. Purposive recruitment with snowball sampling was applied to obtain a heterogeneous sample with an equal proportion of clinicians working in primary and secondary care to reduce the risk of bias [33,34]. Inclusion criteria comprised those currently working as either a general health practitioner or specialist doctor/nurse practitioner within urology or an allied discipline.

Procedure
RUTIIQ items were presented using an online survey tool (REDCap; https:// www. proje ct-redcap. org). In Round 1, the clinicians were asked to rate each for relevance and clarity using a 7-point scale (0 = not at all relevant/clear, 6 = highly relevant/clear) and provide qualitative comments about comprehensiveness and comprehensibility [26,32]. In Round 2, each RUTIIQ item was presented alongside the median relevance and clarity ratings and anonymised qualitative feedback from Round 1. The expert clinicians either retained or updated their original ratings and provided further qualitative feedback.

Data handling
Median ratings from Round 2 were calculated and analysed in conjunction with qualitative feedback. Content validity indices for items (I-CVI) were computed by dividing the number of experts who scored an item's relevance/clarity as at least 4 out of 6 by the total number of experts [35]. A threshold of 0.75 was specified a priori as the minimum I-CVI required to indicate acceptable consensus of content validity, with a minimum median score of 4 [32,34].

Design, setting, and participants
To evaluate how the RUTIIQ may be mentally processed and where problems may arise, one-to-one semi-structured interviews were conducted with rUTI patients using Microsoft Teams [36]. Cognitive debriefing techniques were used to encourage participants to think aloud as they answered the RUTIIQ questions (see Online Resource 5 for all items tested at this stage) [36]. Interviews took place in two phases, with interim iterative refinements validated in the second phase [37].
All cognitive interviews were conducted by the first author to ensure homogeneity in interview style and to facilitate rapport and participant comfort [28,36]. The interviewer had advanced postgraduate training in conducting and analysing qualitative interviews, and ongoing training and quality monitoring were provided by the last author who has extensive expertise as a Chartered Health Psychologist and academic qualitative researcher. To facilitate transcription, all interviews were audio-recorded. Full ethical approval was granted by the School of Psychology and Clinical Language Sciences Research Ethics Committee, University of Reading (project reference: 2021-043-KF). Anonymised recordings were securely stored on the University of Reading server, only accessible to the research team. Data were retained for five years from the study's completion and destroyed sooner if requested. APA guidelines for ethical conduct were maintained at all times [38]. A clinically and demographically diverse sample of 28 adults experiencing rUTI was purposively recruited (see Table 1 for demographic characteristics). To reduce risk of selection bias and sampling error, a large sample representative of the different subgroups that make up the rUTI patient cohort was sought via a broad recruitment strategy with two possible sources: (1) via people signed up to receive newsletters and research notifications from a key stakeholder group: Live UTI Free (https://liveutifree.com), and (2) via other UTI-related online sources, such as support groups. Interested participants were encouraged to share the study information on social media. Recruitment was incentivised using a £25 online shopping voucher prize draw for one random winner, aiming to reduce dropout and attrition bias [39].
Inclusion criteria comprised a minimum age of 18 years old, native or advanced fluency in English, and meeting the diagnostic criteria for rUTI based on self-report [1,18]. Participants who reported a current diagnosis of interstitial cystitis, were using urinary catheterisation, or were pregnant were excluded. Seventy-three potential participants completed a screening survey without exclusion, from which as diverse a sample as possible was selected via maximum variation sampling (see Online Resource 6) [40]. A minimum sample size of 25 participants was sought to achieve confidence that all possible problems with the questionnaire had been identified [26,41]. With a final sample of 28 interviewed participants (n = 18 in the first interview phase, and n = 10 in the second interview phase), sampling adequacy was reached.

Procedure
Participants provided e-consent after reviewing the study's ethical considerations. The interviewer presented the RUTIIQ to participants using a 'screen-share' function and invited them to think aloud their thought processes whilst deciding their answer for each question, allowing evaluation of the measure's overall comprehensiveness and comprehensibility [26,28,37]. Informed by Willis' guidance on planning and conducting cognitive interviews for instrument development [36,37], a topic guide (Online Resource 7) was designed and employed to semi-structure each interview, including scripted probes to encourage elaboration and clarification [37]. Questions about the scale and response options, the time taken to answer questions, and the questionnaire layout and formatting were also asked [36]. Anonymised field notes and written summaries were prepared throughout and following each interview to build richness and support transcript interpretation [37].

Data handling
Anonymised verbatim interview transcripts of the audio recordings were created using speech-to-text transcription software (Otter; https:// otter. ai/), with errors manually corrected. Predefined codes from the Question Appraisal System (QAS-99) [42], designed to support the systematic assessment of questionnaire items and identification of potential problems, were used to support question feature coding. The QAS-99 training manual was applied to create a coding system for the dataset, systematically evaluating every participant response to each RUTIIQ item in relation to question features (for example, comprehension of technical terms). Initial coding was conducted by the first author, with triangulation undertaken by the last author. This assessment was supported by verbatim participant quotes and interviewer field notes [37].
Weekly wider research team meetings were held, allowing for in-depth analysis of transcripts, drawing together a variety of perspectives from expertise including experience in academic mixed-methods research, clinical practice, and patient advocacy. If there were any uncertainties found in Phase 1, the decision was taken to retain the item in Phase 2 and gain further feedback. A third version of the RUTIIQ was created after Phase 1 for assessment in Phase 2, with the same process undertaken at the end of Phase 2 to create a fourth version for pilot testing.

Design, setting, and participants
To collect data for psychometric testing of the RUTIIQ and final item reduction, a two-part cross-sectional survey of adults experiencing rUTI was conducted online. Participants completed the same procedure twice to facilitate test-retest analysis [26][27][28]: (1) at baseline, and (2) 24 h later (Test-Retest Assessment). A maximum time period of 48 h to complete the Test-Retest Assessment was applied following the minimum satisfactory test-retest window advocated by Streiner, Norman & Cairney [43]. This prioritised withinepisode stability and reduced the possibility of a separate rUTI episode altering reporting of rUTI symptom impact [44].
In addition to completing the RUTIIQ, participants completed existing validated measures relating to each RUTIIQ subscale to facilitate construct validity [27,28]. It was hypothesised a priori that there would be moderate to strong correlations (Spearman's ρ > 0.50) between the RUTIIQ subscale scores and existing instruments measuring constructs related to the RUTIIQ subscales ('concurrent measures') [27,28].
A sample of 240 adults meeting the diagnostic criteria for rUTI completed the Baseline Assessment, of whom 106 (44.2%) completed the Test-Retest Assessment (see Table 1 for demographic characteristics, and Online Resource 8 for sampling and recruitment strategy). Participants were recruited using the same recruitment channels used in Stage III, also applying the same inclusion and exclusion criteria. At least 210 participants were required to complete the Baseline Assessment to perform final item reduction via exploratory factor analysis with at least 5 participants per questionnaire item (RUTIIQ = 42 items before final item reduction). Sampling adequacy was exceeded.
Approximately half of the participants (56.3%, n = 135) reported taking antibiotics at the time of participation, either to treat a current UTI, prevent new UTIs, and/or for other indications. Approximately three-quarters (76.3%, n = 183) reported managing their rUTI with non-antibiotic treatment including natural remedies or supplements. More than threequarters of participants (77.5%, n = 186) reported experiencing persistent lower urinary tract symptoms for at least the past three months, with the remainder reporting symptoms which occur on an episodic basis. The mean number of episodes of symptoms reported in the past six months was 6.81 (SD = 24.3), and the mean in the past year was 13.9 (SD = 48.4).

Procedure
In the Baseline Assessment, participants provided e-consent via REDCap after reviewing the study's ethical considerations. Eligible participants who were not excluded during a screening questionnaire proceeded to complete the RUTIIQ and the following six concurrent measures: the Patient Health Questionnaire 9 (PHQ-9) to assess symptoms of depression [45], the Generalized Anxiety Disorder 7 (GAD-7) to assess levels of anxiety [46], the University of Los Angeles Loneliness Scale Version 3 to explore feelings of loneliness and social isolation [47], the Work Productivity and Activity Impairment Questionnaire for Specific Health Problems to evaluate the health-related impact on carrying out work and daily activities [48], the Female Sexual Distress Scale-Revised (FSDS-R) to measure sexual dysfunction [49], and the Patient Satisfaction Questionnaire 18 to assess patient-reported satisfaction with healthcare [50]. The Test-Retest Assessment included the same instruments.

Data handling
After preparing the data for analysis (see Online Resource 9 for data handling strategy [51][52][53][54][55][56][57][58][59][60]), summed scores were calculated for each RUTIIQ subscale and each concurrent measure. Exploratory factor analysis was conducted to perform final item reduction and determine the latent factor structure (structural validity) of the RUTIIQ [26,28,53]. Further psychometric analyses of the RUTIIQ, comprising test-retest reliability, internal consistency, and construct validity, were conducted and compared to gold-standard recommendations [27,28]. Linear regression analyses were also performed to examine any measurement invariance in RUTIIQ scores (for example, related to sociodemographic differences). The Automated Readability Index, a readability measure known to be especially applicable to non-narrative text such as questionnaires [58], was computed to estimate the literacy level required for comprehension of the RUTIIQ.

Stage I: concept elicitation
Framework analysis of the participants' qualitative responses resulted in a conceptual framework comprising five key components: personal wellbeing, social wellbeing, work and activity interference, sexual wellbeing, and patient satisfaction (see Online Resource 3 for thematic framework and supporting verbatim quotations). These were selected for exploration as five subscales in the RUTIIQ, with initial items based on their subcomponents.

Stage II: expert clinician screening
All items achieved I-CVI for relevance and clarity greater than 0.75 and median ratings of at least 4 as specified a priori. Minimal item refinements were implemented based on qualitative recommendations to enhance clarity, by providing more detailed instructions and definitions (see Online Resource 4 for refinements and I-CVI).

Stage III: patient cognitive interviews
Qualitative feedback from patient participants in the cognitive interviews suggested that clarity and comprehensibility could be improved by giving examples and simplifying language (see Online Resource 5 for refinements and verbatim quotations). Refinements made after Phase 1 were tested during Phase 2, after which only minor changes were made with no new items added; data saturation was therefore reached [37].

Exploratory factor analysis
Bartlett's Test of Sphericity was statistically significant (p < 0.001), indicating the absence of multicollinearity [53]. The Kaiser-Meyer-Olkin Measure of Sampling Adequacy estimate was high at 0.89, confirming the suitability of the data for exploratory factor analysis [53]. All extracted communalities were greater than 0.40 except for item A5 (impact on diet), which also did not load above 0.40 on any initial factors and was therefore removed. All other items met these thresholds for communalities and factor loadings. Items demonstrating multiple cross-loadings (B1: impaired close relationships; B3: impaired social activities; B7: worrying about being a burden to others) were removed.
The final five-factor structure comprises the following factors: 'patient satisfaction', 'work and activity interference', 'social wellbeing', 'personal wellbeing', and 'sexual wellbeing' (see Table 2), together accounting for 73.8% of the total variance in scores. They represent a strong fit for the data, clearly distinguishing between the RUTIIQ subscales. The final version of the RUTIIQ consists of 30 items in total (see Table 3; the full questionnaire is available in Online Resource 10).
The final 30-item RUTIIQ consists of five subscales (see Table 3): personal wellbeing (4 items), social impact (5 items), work and activity interference (7 items), sexual wellbeing (4 items), and patient satisfaction (10 items). All five sections utilise an 11-point Likert scale ranging from 0 ('strongly disagree') to 10 ('strongly agree'). For the first four subscales, greater scores indicate greater impact to QoL. For the patient satisfaction subscale, greater scores indicate greater patient satisfaction with UTI-related medical care.

Descriptive statistics and psychometric properties
Observed RUTIIQ subscale scores highlighted the breadth in patient experiences, with scores spanning the full possible range for all subscales except for the sexual wellbeing subscale, for which all participants reported at least some level of impact (see Table 4 for RUTIIQ descriptive statistics, see Online Resource 11 for concurrent measure descriptive statistics). The average PHQ-9 and GAD-7 scores indicated moderate depression (M = 11.5, SD = 7.22) [45], and mild to moderate anxiety (M = 9.23, SD = 6.21) [46], respectively. Participants typically indicated sexual distress considerably beyond the 'normal' FSDS-R range of 0-10 (M = 30.3, SD = 13.7) [49].
The Automated Readability Index for the RUTIIQ is 6.2, indicating suitability for people with a reading age of 11 years old or above [58]. Internal consistency (Cronbach's α), test-retest reliability (ICC), and construct validity (Spearman's ρ) were moderate to strong for all RUTIIQ subscales (see Table 4). All subscale psychometric statistics surpassed the relevant gold-standard recommendations except the sexual wellbeing subscale, which still achieved moderate performance [27,28].
Linear regression analyses indicated the broad sociocultural applicability of the RUTIIQ, indicating no statistically significant group differences in scores in terms of ethnicity, country of residence, relationship status, or level of fluency in English (p > 0.05). Younger respondents typically reported greater rUTI impact than older respondents across all subscales except sexual wellbeing (p < 0.01, see Online Resource 12). Female participants felt that they experienced greater rUTI impact in personal wellbeing, work and activity interference, and sexual wellbeing than male participants (p < 0.05, see Online Resource 13). However, further testing with males is required to examine this difference.

Discussion
This study developed and validated the first patient-reported outcome measure (PROM) of the psychosocial impact of living with rUTI, the Recurrent UTI Impact Questionnaire (RUTIIQ). The 30-item RUTIIQ provides clinicians and researchers with a unique, critically informed, and patientevaluated measure of rUTI impact using five key subscales: personal wellbeing, social wellbeing, work and activity interference, sexual wellbeing, and patient satisfaction. Pilot testing indicated a five-factor structure capable of distinguishing between these concepts, and excellent reliability and validity meeting or exceeding PROM development guidelines [26][27][28].
The unique strengths of the RUTIIQ development and validation included in-depth input from large, heterogeneous, international samples of patients (N = 1983 concept elicitation, N = 28 cognitive interviews, N = 240 pilot) and expert clinicians (N = 15), robustly following gold-standard recommendations and allowing for iterative refinement throughout [26][27][28]. The demographic and clinical diversity of the patient samples suggests the generalisability of the results across a broad spectrum of rUTI patient experiences. The observed psychometric properties and readability statistics of the RUTIIQ indicate its potential for highly effective application to both clinical and research settings.  All five sections of the RUTIIQ utilise an 11-point agreement scale ranging from 0 ('strongly disagree') to 10 ('strongly agree') a The sexual wellbeing subscale (Section D) initially asks respondents whether they feel their sexual wellbeing has been impacted by their UTI symptoms in the past two weeks (response options: 'yes', 'no', 'prefer not to say'). Respondents who indicate 'no' or 'prefer not to say' for this Though the research was robustly conducted in accordance with gold-standard PROM development guidelines, some limitations are acknowledged. This research sampled participants from 24 countries, however it is acknowledged that most patient participants were Caucasian, native English-speaking females residing in high-income countries. Additional cross-cultural validation is therefore necessary. Whilst male participants were included, rUTI is more prevalent amongst females [12]; further evaluation of the psychometric properties of the RUTIIQ with males is required. Further test-retest assessment could be conducted with wider time spacing between original completion and retest, following Streiner, Norman & Cairney [43]. Whilst extensive patient involvement was conducted for the development of the RUTIIQ, further qualitative exploration of this measure from the perspective of expert clinicians would be beneficial to facilitate its use in practice. Furthermore, future research could aim to engage caregivers and family members to develop a caregiverreported adaptation of the RUTIIQ for use in care contexts. question may skip this section and proceed to the final section about satisfaction with UTI-related medical care   Cronbach's alpha (α) was selected as a measure of internal consistency. Interpretation: α = .80-.90 indicates good internal consistency; α = .90-1.00 indicates excellent internal consistency [49]. PROM development guidance recommends minimum Cronbach's α = .70 [22] ICC (single measures), a measure of test-retest reliability of each subscale between the Baseline and Test-Retest Assessments, was computed for each subscale with a two-way mixed effects model with absolute agreement. Interpretation: ICC = .50-.75 indicates moderate reliability; ICC = .75-.90 indicates good reliability; ICC = .90-1.00 indicates excellent reliability [47]. All ICC were statistically significant at p < .001. PROM development guidance recommends minimum ICC = .70 [22] Spearman's ρ was computed as a measure of construct validity. RUTIIQ patient satisfaction subscale scores were reverse scored. The strongest correlation coefficient for each RUTIIQ subscale is in bold. Interpretation of Spearman's ρ: .00 < .10 = negligible, .10-.39 = weak, .40-.69 = moderate, .70-.89 = strong, .90-1.0 = very strong [50]. Statistical significance for construct validity analysis: *p < .05, **p < .01. PROM development guidance recommends minimum Spearman's ρ = .50 [22] M mean, SD standard deviation, ICC intraclass correlation coefficient, CI confidence interval, LB lower bound, UB upper bound, RUTIIQ Recurrent Urinary Tract Infection Impact Questionnaire, PHQ-9 Patient Health Questionnaire 9 [45], GAD-7 Generalized Anxiety Disorder 7 [46], UCLA-LS University of Los Angeles Loneliness Scale Version 3 [47], WPAI:SHP Work Productivity and Activity Impairment Questionnaire for Specific Health Problems [48], FSDS-R Female Sexual Distress Scale-Revised [49], PSQ-18 Patient Satisfaction Questionnaire 18 [ The RUTIIQ could also be further validated against other chronic illness measures and populations. Research assessing the clinical responsiveness of the RUTIIQ is ongoing. The RUTIIQ is the first PROM to specifically assess the patient experience of rUTI psychosocial impact and prioritise the importance of self-report in this unique health context. The UTI Symptom Assessment [61], a symptomfocussed questionnaire for acute UTI, asks respondents to rate how 'bothersome' symptoms are, and the Acute Cystitis Symptom Score [62], a symptom-focussed questionnaire for acute cystitis, includes three brief QoL-related questions. The RUTIIQ goes beyond this to capture a fuller picture of the psychosocial challenges faced by this patient cohort, sensitively exploring distinct areas of impact. Unlike generic QoL measures, the RUTIIQ has been developed and validated specifically for use in the rUTI patient population, allowing for evaluation of the unique interactions between psychological, social, and sexual wellbeing reported by patients.
The lack of capacity to measure the rUTI patient experience has been widely reported [23,25], and the RUTIIQ represents a crucial step towards supplementing well-established clinical testing methods with the patient perspective. Reliable, validated measures of rUTI are essential to improve our understanding of the breadth of challenges associated with this prevalent condition, ultimately improving patient outcomes. Used in conjunction with UTI testing and assessment of symptoms [63], the application of the RUTIIQ in clinical practice allows for standardised observation, patient monitoring, and mapping of patient outcomes [24]. The RUTIIQ enables clinicians to identify how rUTI is impacting their patients, highlighting areas of concern that may require additional support (such as low mood, anxiety, social challenges). This measure has the potential to obtain a sensitive and rapid indication of changes in psychosocial experience over time, and could be used to demonstrate effectiveness of interventions [24].

Conclusion
The RUTIIQ is an important new outcome measure which specifically evaluates the patient-reported experience of rUTI impact, offering a critical, patient-centred tool for the quantification of psychosocial challenges experienced by this patient cohort. The RUTIIQ has demonstrated strong internal consistency, test-retest reliability, and stability, and has been carefully validated against concurrent measures, producing high construct validity. Such rigorous psychometric validation generates confidence in the use of the RUTIIQ in urology, primary care, and wider healthcare settings. By supporting standardised patient observation and monitoring, clinicians and healthcare professionals are now able to quantitatively calibrate those psychosocial challenges requiring intervention beyond UTI symptom experiences, assessing the effectiveness of their interventions. The RUTIIQ critically prioritises the examination of quality-of-life impact and its uptake will influence both healthcare policy and practice from a patient-centred perspective.
Author contributions All authors contributed to the study conception and design. Material preparation and data collection for Stage I was conducted by KM. Material preparation and data collection for Stages II, III and IV were conducted by AFN. Data analysis was conducted by AFN and KF. MK and JLP supported participant recruitment via Live UTI Free. The original draft of the manuscript was written by AFN and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.
Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
Data availability Raw data from this research study and the final Recurrent UTI Impact Questionnaire is archived and accessible in the Open Science Framework data repository: https:// osf. io/ q2svk (https:// doi. org/ 10. 17605/ OSF. IO/ Q2SVK).

Declarations
Competing interests Melissa Kramer is CEO of Live UTI Free Ltd. (https:// liveu tifree. com); however, no financial incentives have been received.
Ethical approval and consent to participate Ethical approval was granted by the School of Psychology and Clinical Language Sciences Ethics Committee, University of Reading (project reference: 2021-043-KF). All individual participants were provided with study information sheets and debrief forms, and informed electronic consent was obtained from all.

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