URINARY STONES AND INTERVENTION QUALITY OF LIFE (USIQOL) – DEVELOPMENT AND VALIDATION OF A COMPREHENSIVE PATIENT REPORTED OUTCOME MEASURE
Urolithiasis has a range of symptoms and involves many treatment options which can have significant impact on patients' health-related quality of life (HRQoL). There is a need for patient reported outcome measure (PROM) to evaluate this impact. We developed Urinary stones and Intervention quality of Life (USIQoL), a new multidimensional PROM that would form a valid outcome measure.
Adult patients with urinary (renal and ureteral) stones covering all index stone categories were asked to participate in different phases (over 350 patients). Phase 1 included literature review and qualitative research involving semistructured patient and focus group interviews with thematic analysis. This formed the foundation for the initial long draft of the USIQoL. Phase 2 included cognitive debriefing, pilot testing alongside review of the measure by a panel of international urologists. Phase 3 involved RASCH (internal construct) analysis (partial credit model) and validity and reliability (external construct) assessments by administering the new measure to the patients, before and after medical and surgical treatments, with metabolic abnormalities disease as well as no active treatments. Patients also completed existing tools (SF12, EuroQoL, HADS, USSQ) to evaluate concurrent validity to develop the final draft of the measure.
Mean patient age was 51 years (range 18-92) with male patient predominance (65%). Phase 1 studies (qualitative research) involved 80 patients and 30 family members. The results identified significant negative QoL impact affecting pain, physical and psycho-social domains along with concerns, specific to stones and treatments, such as employment, travel and need of support. The thematic analyses formed the basis for the initial 60 item multidimensional long draft of the USIQoL. Phase 2 showed that the tool had ace content validity with all stakeholders confirming adequacy of the instrument. In phase 3 the RASCH polytomous analysis identified redundant items and helped develop final 20 item version with good item, personal fit and satisfactory separation index. The measure covers all relevant domains of health (pain, physical and psychosocial) along with stone and intervention specific factors. The validation studies showed questionnaire to be internally consistent (cronebach’s alpha>0.7) and reliable (Pearson coefficient>0.8) with satisfactory sensitivity to change (p