Incidence and trends in the treatment of kidney stones in Canada A population-based cohort study.

INTRODUCTION: Our objective was to assess the incidence of kidney stones requiring acute care, trends in the surgical treatment of stones, and the demographics of stone formers in Canada. METHODS: We conducted a population-based, retrospective cohort study using administrative data from the Canadian Institute for Health Information. We included Canadian residents age >18 years, outside of Quebec, who presented between January 1, 2013, and December 31, 2018, with a kidney stone episode. This was defined as a kidney stone resulting in hospital admission, emergency department visit, or stone intervention, specifically shockwave lithotripsy (SWL), ureteroscopy (URS), or percutaneous nephrolithotomy (PCNL). RESULTS: There were 471 824 kidney stone episodes, including 184 373 interventions. The number of kidney stone episode increased from 277/100 000 in 2013 to 290/100 000 in 2018. The median age was 53 (interquartile range 41-65) years and 59.9% were male. The crude rate for stone intervention was 877/100 000. The age- and gender-standardized rate for interventions was highest in Nova Scotia and Newfoundland and Labrador, and lowest in Prince Edward Island. The most common intervention in Canada was URS (73.5%), followed by SWL (19.8%) and PCNL (6.7%). The percent utilization of SWL was highest in Manitoba, whereas for URS, it was highest in Prince Edward Island and Alberta. CONCLUSIONS: Our study provides the first population-based data on the demographics of stone formers and treatment trends across Canada. There has been a 4.7% increase in kidney stone episodes over the study period. Those presenting to hospital or requiring intervention for a kidney stone are more likely to be male, aged 41-65, and undergo URS.

The impact of kidney stone disease on quality of life in high-risk stone formers.

OBJECTIVE: To assess the impact of kidney stone disease (KSD) and its treatment on the health-related quality of life (HRQOL) of high-risk stone formers with hyperparathyroidism, renal tubular acidosis, malabsorptive disease, and medullary sponge kidney. PATIENTS AND METHODS: The Wisconsin Stone Quality of Life questionnaire was used to evaluate HRQOL in 3301 patients with a history of KSD from 16 institutions in North America between 2014 and 2020. Baseline characteristics and medical history were collected from patients, while active KSD was confirmed through radiological imaging. The high-risk group was compared to the remaining patients (control group) using the Wilcoxon rank-sum test. RESULTS: Of 1499 patients with active KSD included in the study, the high-risk group included 120 patients. The high-risk group had significantly lower HRQOL scores compared to the control group (P < 0.01). In the multivariable analyses, medullary sponge kidney disease and renal tubular acidosis were independent predictors of poorer HRQOL, while alkali therapy was an independent predictor of better HRQOL (all P < 0.01). CONCLUSIONS: Among patients with active KSD, high-risk stone formers had impaired HRQOL with medullary sponge kidney disease and renal tubular acidosis being independent predictors of poorer HRQOL. Clinicians should seek to identify these patients earlier as they would benefit from prompt treatment and prevention.

Can Perioperative Antibiotic Choice Impact Rates of Infectious Complications After Percutaneous Nephrolithotomy? A Single-Blind, Prospective Randomized Trial.

Objective: National guidelines recommend periprocedural antibiotics before percutaneous nephrolithotomy (PCNL), yet it is not clear which is superior. We conducted a randomized trial to compare two guideline-recommended antibiotics: ciprofloxacin (cipro) vs cefazolin, on PCNL outcomes, focusing on the development of systemic inflammatory response syndrome (SIRS) criteria. Methods: Adult patients who were not considered high risk for surgical or infectious complications and undergoing PCNL were randomized to receive either cipro or cefazolin perioperatively. All had negative preoperative urine cultures. Demographic and perioperative data were collected, including SIRS criteria, intraoperative urine culture, duration of hospitalization, and need for intensive care. SIRS is defined by ≥2 of the following: body temperature <96.8°F or >100.4°F, heart rate >90 bpm, respiratory rate >20 per minute, and white blood cell count <4000 or >12,000 cells/mm3. Results: One hundred forty-seven patients were enrolled and randomized (79 cefazolin and 68 cipro). All preoperative characteristics were similar (p > 0.05), except for mean age, which was higher in the cipro group (64 vs 57 years, p = 0.03). Intra- and postoperative findings were similar, with no difference between groups (p > 0.05), except a longer mean hospital stay in the cefazolin group (2 hours longer, p = 0.02). There was no difference between SIRS episodes in both univariate and multivariate analyses. Conclusions: Despite the relatively broader coverage for urinary tract pathogens with ciprofloxacin, this prospective randomized trial did not show superiority over cefazolin. Our findings therefore support two appropriate options for perioperative antibiotic prophylaxis in patients undergoing PCNL who are nonhigh risk for infectious complications.

Comparison of Radiation Exposure for Pregnant Patients Requiring Intervention for Suspected Obstructing Nephrolithiasis.

OBJECTIVE: To identify the differences in radiation exposure per suspected stone episode between percutaneous nephrostomy tube (PCN), stent, and primary ureteroscopy (URS).The incidence of nephrolithiasis in pregnancy is low; however, repercussions for both mother and fetus can be significant. In cases of suspected obstructing nephrolithiasis, intervention may be required, including ureteral stent, PCN, or URS, with the potential for multiple subsequent procedures that often utilize fluoroscopy. METHODS: Pregnant patients who required an intervention (stent, PCN, or URS) for suspected obstructing nephrolithiasis were retrospectively reviewed. The primary outcome was total fluoroscopy exposure per suspected stone episode. Secondary outcomes included fluoroscopic exposure per procedure and number of procedures required. RESULTS: After excluding patients with renal anomalies and incomplete radiation data, 78 out of 100 patients were included in the analysis. Forty patients (51.3%) underwent initial stent placement, 22 (28.2%) underwent initial PCN placement, and 16 (20.5%) underwent primary URS. Total mean radiation exposure per stone episode was significantly higher in patients who underwent PCN, (286.9 mGy vs 3.7 mGy (stent) and 0.2 mGy (URS), P <.001). In addition, patients who underwent initial PCN placement had significantly more procedures (P <.001) and mean radiation exposure per procedure was higher (P <.001). More than 40% of PCNs experienced dysfunction, and mean duration between PCN exchanges was 16.5 days. CONCLUSION: In pregnant patients with suspected obstructing nephrolithiasis requiring intervention, initial PCN placement was associated with a significantly higher number of procedures, radiation exposure per procedure, and total radiation exposure per suspected stone episode compared to stent and URS.

The Effect of Pre-Stenting on Bleeding-Related Complications Following Ureteroscopy in Patients on Anticoagulation or Antiplatelet Therapy.

Introduction: The American Urological Association guidelines state that continuing anticoagulant (AC) and antiplatelet (AP) agents during ureteroscopy (URS) is safe. Through a multi-institutional retrospective study, we sought to determine whether pre-stenting in patients on AP or AC was associated with fewer URS bleeding-related complications. Methods: A series of 8614 URS procedures performed across three institutions (April 2010 to September 2017) was electronically reviewed for AC/AP use at time of URS. Records indicating AC or AP use at time of URS were then manually reviewed to characterize intraoperative and 30-day postoperative (intraoperative bleeding, postoperative hematuria, emergency department visits, hospital readmission, unplanned reoperation, phone calls, and other minor 30-day complications). Results: A total of 293 identified URS procedures were completed on patients on AC/AP therapy-112 cases were on AC only (38 were pre-stented), 158 on AP only (51 pre-stented), and 23 on both AP and AC (8 pre-stented). Patient characteristics and comorbidities were similar between the pre-stented and non-pre-stented groups. For AC and AP subjects, pre-stenting did not decrease the composite risk of bleeding complications (10.3% pre-stent vs 12.2% non-prestent, p = 0.6). Pre-stented patients did have a significantly lower likelihood of requiring an unplanned reoperation (1.0% vs 5.6%, p = 0.04). In the subgroup of patients on AP alone, pre-stented patients had significantly fewer episodes of intraoperative bleeding (0% vs 9%, p = 0.04), unplanned reoperations (0% vs 6.5%, p = 0.02), and 30-day complications (14% vs 27%, p = 0.05). In the subgroup of patients on AC alone, there were no significant differences in outcomes based on stent status. Conclusions: In this multi-institutional study, we found that pre-stenting before URS was not associated with fewer bleeding complications. However, pre-stenting appeared to be associated with improved outcomes for those patients on AP therapy. These results suggest a need for prospective studies to clarify the role of pre-stenting for URS.

The Impact of Bilateral Stone Disease on Patients' Disease Progression and Health-Related Quality of Life.

Purpose: Patients with recurring kidney stone events can expect significant morbidity and functional impairment. Few studies have evaluated the effect of bilateral kidney stones on disease progression and quality of life. We wanted to determine the association of bilateral stone disease on age of onset, and the impact on number of stone events and individual kidney stone disease-specific health-related quality of life (HRQOL) by analyzing the validated and prospectively collected Wisconsin Stone Quality of Life (WISQOL) database. Materials and Methods: We studied 2906 stone patients from 16 centers in North America after having completed the WISQOL questionnaire from 2014 to 2019. Kidney stone formers were assessed if kidney stones were bilateral or unilateral on imaging. Analysis with a chi-square test compared categorical variables. Bilateral kidney stone disease and its impact on HRQOL were evaluated through a multivariable linear regression model. Results: Of 2906 kidney stone formers, 1340 had unilateral kidney stones and 1566 had bilateral kidney stones. We observed more frequently that patients with bilateral stones had an increased number of depression/anxiety symptoms, renal tubular acidosis, and rheumatoid arthritis (all p < 0.05). Patients with bilateral stones had a younger mean (standard deviation [SD]) age of kidney stone disease onset (37.2 ± 15.8 vs 46.4 ± 15.9 years of age, p < 0.001). Bilateral kidney stone formers had a higher mean (SD) number of stone events (11.3 ± 21.8) than unilateral kidney stone formers (3.0 ± 5.1) (p < 0.001). Within our multivariable analysis, we found that HRQOL was negatively affected by the presence of bilateral stones for kidney stone patients (ß = -11.2 [confidence interval: -19.5 to -3.0] points, p < 0.05). Conclusions: Bilateral kidney stone formers had a younger age of kidney stone disease onset and a higher number of stone events compared with unilateral kidney stone disease formers. The presence of bilateral kidney stone disease negatively impacted HRQOL.

Long-term follow-up on dusting versus basketing during ureteroscopy: a prospective multicenter trial from the EDGE Research Consortium.

In 2018, the Endourology Disease Group for Excellence (EDGE) published a prospective trial comparing dusting versus basketing during ureteroscopy. One hundred fifty-nine patients were included in the original analysis, which found no difference in stone-free rate at 3 months. We report the intermediate and long-term outcomes of patients included in the original trial. Two analyses were performed. At 1-year, a retrospective chart review was performed, and data collected on stone episodes, Emergency Department (ED) visits, hospital admissions and surgical interventions. To obtain long-term outcomes, the four sites with the largest initial accrual were included in a second phase of data collection with updated analyses. The patients from those sites were contacted, re-consented, and data were collected on stone surgical interventions, stone episodes, stone recurrences on imaging, emergency department (ED) visits, and hospital admissions for stone-related care since their original procedure. One-year follow-up data were collected in 111 of the original 159 (69.8%) patients from the nine sites. There were no statistically significant differences in the number of painful episodes, ED visits, hospital admissions, or surgical interventions. 94 patients from four sites were included in the long-term analysis. There were no statistically significant differences in surgical interventions, painful stone episodes, stone recurrence on imaging, ED visits or hospitalizations for stone-related events between the two groups. Long-term outcomes of dusting versus basketing during ureteroscopy indicate that there are no significant differences in clinical outcomes between the two surgical modalities.

The Duration of Stone Disease and the Impact of a Stone Event on Patients' Quality of Life.

Introduction: With a 5-year stone recurrence rate of 30% to 50%, kidney stone formers are subject to significant morbidity that negatively impacts their health-related quality of life (HRQOL). We sought to determine the impact of age at kidney stone onset, duration of stone disease, and kidney stone event (surgery or stone passage) on HRQOL of individual patients by querying the validated and prospectively collected Wisconsin Stone Quality of Life (WISQOL) database. Patients and Methods: Cross-sectional data were obtained from a total of 2438 kidney stone formers from 14 institutions in North America who completed the WISQOL questionnaire during the period from 2014 to 2019. The 28-question survey has a 1- to 5-point scale for each item (total score range 0-140). Multivariable linear regression models assessed the impact of age at kidney stone onset, duration of stone disease, and time since most recent surgery or stone passage on HRQOL. Results: Of 2438 patients, older age at kidney stone onset and longer duration of disease were both independent predictors of better WISQOL scores (ß = 0.33 points/year; confidence interval [CI] 0.17-0.49; p < 0.001; and ß = 0.50 points/year; CI 0.32-0.68; p < 0.001, respectively). Of 1376 patients who underwent surgery between 2010 and 2019, longer time since most recent surgery was an independent predictor of better WISQOL scores (ß = 2.28 points/year; CI: 1.47-3.10; p = <0.001). Of 1027 patients with spontaneous stone passage occurring between 2010 and 2019, longer time since most recent stone passage was an independent predictor of better WISQOL scores (ß = 1.59 points/year; CI: 0.59-2.59; p = <0.05). Conclusions: Our study demonstrates that older age at onset, longer duration of disease, and longer time since most recent surgery or stone passage were independent predictors of better HRQOL in kidney stone formers. Results of future studies that focus on optimizing stone-related modifiable risk factors to decrease the number of recurrent stone episodes and thus the need for recurrent surgeries will be essential.

The impact of smart technology on adherence rates and fluid management in the prevention of kidney stones.

Smart technology (ST) can enhance chronic disease management, yet little is known about the benefits of ST on kidney stone prevention. Our aim was to prospectively evaluate the impact of ST on follow-up adherence rates and urine output (UOP) in patients with nephrolithiasis. Kidney stone patients with low UOP (< 2.5 L/24 h) were randomized into three intervention groups: (1) standard dietary/medical counseling alone (control), (2) control + smartphone fluid management application (app), and (3) control + smart water bottle (bottle). Demographics, adherence rates, kidney stone events, and 24 h urine data were collected and analyzed at baseline, 3-6, and 12 months. We randomized 111 patients (37 per group), of which 20 (55%), 8 (26%), and 10 (33%) patients completed the 12 month follow-up in the control, app, and bottle groups respectively. Control group patients were the most likely to adhere to follow-up (p = 0.004). Overall mean UOP increased by 0.4 L in each group (p < 0.05), with no difference in mean baseline 24 h UOP (1.6 L) and 12 month 24 h UOP (2.0 L) between groups (p > 0.05). Twenty-nine percent of patients achieved a daily UOP goal of > 2.5 L across the treatment groups (p < 0.001). In this prospective study, the 24 h UOP improved across all groups compared to baseline, although adherence to follow-up remained low. Furthermore, the use of ST did not further augment UOP, underscoring the importance of dietary/medical counseling for kidney stone prevention.

SKOPE-Study of Ketorolac vs Opioid for Pain after Endoscopy: A Double-Blinded Randomized Control Trial in Patients Undergoing Ureteroscopy.

PURPOSE: Pain is the leading cause of unplanned emergency department visits and readmissions after ureteroscopy, making postoperative analgesic stewardship a priority given the current opioid epidemic. We conducted a double-blinded, randomized controlled trial, with noninferiority design, comparing nonsteroidal anti-inflammatory drugs to opiates for postoperative pain control in patients undergoing ureteroscopy for urolithiasis. MATERIALS AND METHODS: Patients were randomized and blinded to either oxycodone (5 mg) or ketorolac (10 mg), taken as needed, with 3 nonblinded oxycodone rescue pills for breakthrough pain. Primary study outcome was visual analogue scale pain score on postoperative days 1-5. Secondary outcomes included medication utilization, side effects, and Ureteral Stent Symptom Questionnaire scores. RESULTS: A total of 81 patients were included (43 oxycodone, 38 ketorolac). The 2 groups had comparable patient, stone, and perioperative characteristics. No differences were found in postoperative pain scores, study medication or rescue pill usage, or side effects. Higher maximum pain scores on days 1-5 (p <0.05) and higher questionnaire score (28.1 vs 21.7, p=0.045) correlated with analgesic usage, irrespective of treatment group. Patients receiving ketorolac reported significantly fewer days confined to bed (mean±SD 1.3±1.3 vs 2.3±2.6, p=0.02). There was no difference in unscheduled postoperative physician encounters. CONCLUSIONS: This is the first double-blinded randomized controlled trial comparing nonsteroidal anti-inflammatory drugs and opiates post-ureteroscopy, and demonstrates noninferiority of nonsteroidal anti-inflammatory drugs in pain control with similar efficacy, safety profile, physician contact and notably, earlier convalescence compared to the opioid group. This provides strong evidence against routine opioid use post-ureteroscopy, justifying continued investigation into reducing postoperative opiate prescriptions.

The impact of the number of lifetime stone events on quality of life: results from the North American Stone Quality of Life Consortium.

To evaluate the impact of chronic stone recurrence on an individual's quality of life using the validated Wisconsin Stone Quality of Life (WISQOL) questionnaire. We collected cross-sectional data on patients with kidney stones from 14 institutions in North America. A stone event was defined as renal colic, stone-related procedure or emergency department visit. The regression analyses using general linear models and pairwise comparison determined the impact of the number of stone events on quality of life. The median number of stone events among the 2205 patients who completed the questionnaire was 3 (IQR 1-6). The mean total score was 107.4 ± 28.7 (max 140 points). The number of lifetime stone events was an independent predictor of lower quality of life (p < 0.001), specifically, score declined significantly beyond five events. Compared with patients who experienced a single stone event, there was a 0.4, 2.5, and 6.9 point decline in the adjusted mean WISQOL score after 2-5, 6-10, or > 10 events, respectively. The cumulative number of lifetime stone events was associated with a lower quality of life when more than five stone events were occurred. These findings underscore the importance of efforts to determine the underlying metabolic etiology of urolithiasis in the recurrent stone former, and the institution of a regimen to place their stone disease in remission.

Can CT-Based Stone Impaction Markers Augment the Predictive Ability of Spontaneous Stone Passage?

Introduction: A number of clinical and radiological predictors of either stone impaction or ureteral stone passage (SP) have been proposed. We aimed at identifying the key predictors of successful SP by using readily available CT-based tools/measurements. Methods: Patients presenting to the emergency department from February 2017 to February 2018 with an acute unilateral ureteral stone confirmed on non-contrast CT and managed conservatively were followed for SP. Patients with renal impairment, sepsis or requiring emergent intervention were excluded. Patients were followed at 1 month to confirm SP (stone collection/repeat imaging) or failure of passage. The CT variables analyzed included: Stone factors [location, size, volume, HU density (HUD)], impaction factors [ureteral HUD above and below the stone, maximal ureteral wall thickness (UWT) at the stone site, contralateral UWT, and ureteral diameter above and below the stone]. Binary logistic regression analysis was performed to identify predictors of SP. Results: Forty-nine patients met study inclusion criteria, of whom 32 (65.3%) passed the stone without further intervention. Patients with successful passage were more likely to have smaller, lower volume and less dense stones located in the distal ureter (p < 0.01). Lower ureteral HUD below the stone, lower maximal UWT, and lower ureteral diameter above the stone were associated with successful passage (p < 0.01). On multivariable logistic regression analysis, only maximal UWT at the stone site was a significant independent predictor of SP outcome (p = 0.01). Youden's criterion identified 2.3 mm as the optimal UWT cut-off point, which will accurately predict SP with 82.4% sensitivity and 87.5% specificity. Conclusions: Maximal UWT at the stone site was the most significant predictor of successful passage in acute unilateral ureteral stones, with an optimal cut-off point of 2.3 mm. Further prospective studies are needed to accurately predict spontaneous SP.

Utility of stone volume estimated by software algorithm in predicting success of medical expulsive therapy.

INTRODUCTION: We sought to assess the accuracy of using stone volume (SV) estimated with a software algorithm as a predictor for stone passage in a trial of medical expulsive therapy (MET). METHODS: We identified patients with ureteral stones discharged from the emergency department on MET. Patients with infection, non-ureteral stones, or needing immediate surgical intervention were excluded. For each stone, longest dimension (LD) was recorded, and SV was estimated by a computed tomography (CT)-based region-growing (RG) algorithm and standard ellipsoid formula (EF). Stone passage within 30 days was assessed via electronic chart and followup phone call. RESULTS: Fifty-one patients were included for analysis (53±16.7 years, 24% female). The mean LD was 4.85±2.02 mm. The mean SV was similar by EF and RG (0.051±0.057cm3 vs. 0.049±0.052 cm3, p=0.28). Thirty-three (65%) patients passed their stone, while 18 (35%) did not. The mean LD for passed stones vs. failed passage was 4.1±1.7 mm vs. 6.2±1.8 mm (p=0.0002); the mean EF volume was 0.028±0.035 cm3 vs. 0.093±0.066 cm3 (p=0.00007); and the mean volume by RG was 0.028±0.027 cm3 vs. 0.088±0.063 cm3 (p=0.00005). CONCLUSIONS: The clinical utility of SV estimated by software algorithm as a predictor for success of MET has not previously been examined. We demonstrated that spontaneously passed stones had a significantly smaller volume than those requiring intervention. Further prospective studies are needed to validate these findings and establish volume thresholds for probability of stone passage.

Estimating the health-related quality of life of kidney stone patients: initial results from the Wisconsin Stone Quality of Life Machine-Learning Algorithm (WISQOL-MLA).

OBJECTIVE: To build the Wisconsin Stone Quality of Life Machine-Learning Algorithm (WISQOL-MLA) to predict urolithiasis patients' health-related quality of life (HRQoL) based on demographic, symptomatic and clinical data collected for the validation of the Wisconsin Stone Quality-of-Life (WISQOL) questionnaire, an HRQoL measurement tool designed specifically for patients with kidney stones. MATERIAL AND METHODS: We used data from 3206 stone patients from 16 centres. We used gradient-boosting and deep-learning models to predict HRQoL scores. We also stratified HRQoL scores by quintile. The dataset was split using a standard 70%/10%/20% training/validation/testing ratio. Regression performance was evaluated using Pearson's correlation. Classification was evaluated with an area under the receiver-operating characteristic curve (AUROC). RESULTS: Gradient boosting obtained a test correlation of 0.62. Deep learning obtained a correlation of 0.59. Multivariate regression achieved a correlation of 0.44. Quintile stratification of all patients in the WISQOL dataset obtained an average test AUROC of 0.70 for the five classes. The model performed best in identifying the lowest (0.79) and highest quintiles (0.83) of HRQoL. Feature importance analysis showed that the model weighs in clinically relevant factors to estimate HRQoL, such as symptomatic status, body mass index and age. CONCLUSIONS: Harnessing the power of the WISQOL questionnaire, our initial results indicate that the WISQOL-MLA can adequately predict a stone patient's HRQoL from readily available clinical information. The algorithm adequately relies on relevant clinical factors to make its HRQoL predictions. Future improvements to the model are needed for direct clinical applications.