Presentation Authors: Mostafa Ragab, Salisbury, United Kingdom, Jane Collie, Nikolay Baldin, Cambridge, United Kingdom, Maxine Tran, London, United Kingdom, James Armitage, Samih Al Hayek, Oliver Wiseman*, Cambridge, United Kingdom
Introduction: Outcomes from surgery have traditionally been based on surgeon-reported outcomes. A paradigm shift in assessing healthcare productivity from output to qualitative outcome has led to increased interest in patient-reported outcome measures (PROMs). Our study describes the development and validation of the disease specific Cambridge renal stone PROM (CRESP).
Methods: Patients with radiologically proven renal calculi who had undergone a range of management options were invited to participate in focus groups or semi-structured interviews, to elicit patient input and generation of CRESP content until reaching saturation. Validity studies included Cronbach's alpha for internal consistency, Spearman's and Pearson's correlation coefficients for test-retest reliability. Discriminant validity was assessed by Pearson's correlation versus EQ5D5L. Our project has Health and Social Care Research Ethics Committee approval.
Results: A total of 86 patients participated in creating CRESP. 36 patients were invited to 22 semi-structured interviews and 4 focus groups. Major issues reported and themes selected for the PROM included pain, anxiety, limitations to social life and tiredness, urinary symptoms, dietary changes' impacts and gastrointestinal symptoms. Reliability analysis for 30 patients to determine internal consistency using Cronbach's alpha with a mean of 0.91 (range 0.90 to 0.93) and Cronbach's alpha between domains was 0.92. Average inter-item Pearson's and Spearman's correlation within domains was performed, with Pearson's correlation mean of 0.77 (range 0.73 to 0.85) and Spearman's correlation mean of 0.72 (range 0.63 to 0.77). Test-retest Pearson's correlation mean was 0.85 (range 0.57 to 0.95). Discriminant validity assessment was performed by comparing the averages of the scores of 2 groups of 40 patients and controls for each domain of CRESP, The mean scores of patients were systematically larger than the ones of control (Figure). Pearson's correlation with EQ5D5L was -0.74, showing the newly developed CRESP successfully discriminated patients suffering from kidney stones.
Conclusions: Our validated patient-derived CRESP is a new instrument, specifically tailored to measure renal stone disease health outcomes from the patient's point of view.