Qualitative exploration of the renal stone patients' experience and development of the renal stone-specific patient-reported outcome measure.

OBJECTIVES: To investigate the experience of patients living with renal calculi via a qualitative methodology, aiming to develop and validate a disease-specific patient-reported outcome measure (PROM) for renal stones, the Cambridge Renal Stone PROM (CReSP). PATIENTS, SUBJECTS AND METHODS: Patients with radiologically confirmed renal calculi who had undergone a range of management options were invited to focus groups or semi-structured interviews to elicit patient input and generate the PROM content. The developed renal stone PROM underwent validity studies included Cronbach's α for internal consistency, Spearman's and Pearson's correlation coefficients for test-retest reliability. Discriminant validity was assessed by Pearson's correlation coefficients vs the EuroQol five-dimensional five-level questionnaire (EQ-5D-5L). Our project has Health and Social Care Research Ethics Committee approval. RESULTS: A total of 106 subjects participated in creating the newly developed PROM. In all, 36 patients were invited to 22 semi-structured interviews and four focus groups, until reaching saturation. Major issues reported, and themes selected for the renal stone PROM included pain, anxiety, limitations to social life and tiredness, urinary symptoms, dietary changes' impacts, and gastrointestinal tract symptoms. Reliability analysis for 30 patients to determine internal consistency using Cronbach's α with a mean (range) of 0.91 (0.90-0.93) within domains and Cronbach's α between domains was 0.92. Average inter-item Pearson's and Spearman's correlation within domains was performed, with a Pearson's correlation mean (range) of 0.77 (0.73-0.85) and Spearman's correlation mean (range) of 0.72 (0.63-0.77). The test-retest Pearson's correlation mean (range) was 0.85 (0.57-0.95). Validity assessment was performed for 20 patients vs 20 controls. Pearson's correlation with EQ-5D-5L was -0.74, showing the newly developed PROM successfully discriminated patients with kidney stones. Our final renal stone PROM consists of 14 questions that are rated on a Likert scale; the higher the score, the worse the effect on a patient's quality of life. CONCLUSIONS: Although pain was the most frequent symptom, other health-related and social well-being issues significantly impacted patients' lives. 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.

Development of a Disease-Specific Ureteral Calculus Patient Reported Outcome Measurement Instrument.

INTRODUCTION: Patient reported outcome measures (PROMs) are powerful instruments to assess the impact of a disease on health from the patient's perspective. We describe the process of designing, testing, and validating the Cambridge Ureteral Stone PROM (CUSP). MATERIALS AND METHODS: Patients recently diagnosed with ureteral stones were approached for participation in focus groups, structured interviews, and test-retest validation studies. Statistical tests included Cronbach's alpha for internal consistency, Spearman's and Pearson's correlation coefficients for test-retest validity, permutation tests of equality of means and Spearman's correlation coefficients for discriminant validity. RESULTS: Forty-three patients participated in the development of the CUSP. Twenty-two patients were involved in the focus groups and structured interviews and a further 21 participated in the prospective test-retest study. Expressed comments were grouped into seven broad health domains: pain, fatigue, sleep disturbance, work and daily activities, anxiety, gastrointestinal (GI) symptoms, and urinary symptoms. Items were selected from established PROM platforms to form the draft (dCUSP) instrument, which was then used for test-retest validation and item reduction. All domains scored highly for Cronbach's alpha (>0.8), with the exception of GI symptoms. Large Spearman's (>0.76) and Pearson's correlation estimates (>0.83) were obtained for test-retest validity, suggesting that answers were reliable through the time period tested. The estimates of the Spearman's correlation coefficient between each pair of domains ranged from 0.17 to 0.78 and the upper bounds of the corresponding 95% confidence intervals were all smaller than 0.95, suggesting that each domain measures something different. The tests of equality of the mean of scores of the control (n = 25) and patient groups were all significant, suggesting that CUSP successfully discriminated patients suffering from ureteral stones for every domain. CONCLUSION: CUSP is a patient-derived ureteral stone PROM, which can be used to measure ureteral stone disease health outcomes from the patient's point of view.

Do renal stones that fail lithotripsy require treatment?

The rates of extracorporeal shock wave lithotripsy (SWL) appear stable in the UK. However, there is little evidence on the natural history of these calculi if SWL fails. We set to look at the effectiveness of SWL in patients with a single, previously untreated renal stone and the natural history of those stones that failed treatment. We retrospectively reviewed all data from our prospectively collected database of patients undergoing a first treatment for a single renal stone between October 2010 and November 2013. Outcomes after SWL were categorised as success, subsequent intervention needed or conservative management. The medical records of patients managed conservatively were reviewed to determine whether further intervention was required and why. We further sought to define, in those patients where SWL failed, whether subsequent active intervention was needed. For the remainder, we examined whether conservative management was a reasonable management option. 313 patients fitted the inclusion criteria. Of these, 144 were treated successfully. Of the 170 patients with a residual stone, 51 went on to flexible ureteroscopy directly at their next clinical review mainly due to persistent symptoms. 79 patients were managed conservatively, and for 39 follow-up data were unavailable as their follow-up was at a different hospital. 63 patients (80%) were successfully managed conservatively with no recurrence of symptoms over the follow-up period (mean 2 years 4 months). 16 (20%) patients that were initially managed conservatively required subsequent intervention. Of these, 87% had a stone in an upper pole calyx. Conservative management of renal stones after failed SWL is a suitable option for asymptomatic patients with stones not located in the upper pole. For patients with upper pole stones, early intervention is warranted due to the high risk of requiring intervention.