MAGNESIUM SUPPLEMENTATION INCREASES URINE MAGNESIUM AND CITRATE IN STONE FORMERS WITH HYPOMAGNESURIA.

OBJECTIVES: To compare the effects of magnesium repletion by a foods-alone approach or by magnesium supplementation on urinary magnesium and citrate excretion in patients with urine magnesium <70 mg/day. METHODS: We reviewed medical records of patients in our stone prevention practice who were advised to start a magnesium supplement (Sup), 250-500 mg/d, or increase dietary magnesium consumption. We included adults with 24h UMg <70 mg, those who received magnesium recommendations (corroborated by the dietitian's clinical notes), and those with a follow-up 24h urine collection ≤18 months. Urine results were assessed by group. RESULTS: Groups [No Sup (n=74) and Sup (n=56)] were not different for age, gender, stone history, malabsorption, or other clinical indices. All patients raised UMg (53 to 69 and 47 to 87 mg/d for No Sup and Sup, respectively); however, the increase was significantly higher in the Sup group. Moreover, while 88% of Sup patients achieved UMg ≥70 mg/d, only 58% in the No Sup group did so. Within-group increases in urine citrate were significant only in the Sup group. CONCLUSION: Among patients with low UMg, both higher consumption from foods and magnesium supplementation significantly increased UMg. However, those who supplemented were significantly more likely to reach or exceed UMg 70 mg/d and achieved higher mean UMg. The change in urine citrate was significant only among those in the Sup group.

Advancements in surgical education: exploring animal and simulation models in fetal and neonatal surgery training.

Introduction: Surgical education is undergoing a transformation, moving away from traditional models towards more modern approaches that integrate experiential and didactic methods. This shift is particularly pertinent in the realm of fetal and neonatal surgery, where specialized training is crucial. Historical training methods, such as cadaveric dissection, have been prevalent for centuries, but newer innovations, including animal and non-animal simulation models, are gaining prominence. This manuscript aims to explore the use of both animal and non-animal models in surgical education, with a specific focus on fetal and neonatal surgery. Animal models: The use of animal models in surgical training has a long history, dating back to Halsted's introduction in 1889. These models, often utilizing large animals like swine and dogs, offer valuable insights into fetal and neonatal surgeries. They allow for the study of long-term outcomes and the simulation of various diseases and anomalies, providing essential training experiences not readily available in human surgeries. However, there are notable limitations, including anatomical and physiological differences from humans, ethical considerations, and substantial infrastructure and maintenance costs. Simulation models: Simulation-based training offers several benefits, including standardized and safe learning environments without risks to real patients. Bench models, using synthetic materials or non-living animal tissue, provide cost-effective options for skills development. Virtual reality and 3-D printing technologies further enhance simulation experiences, allowing for the replication of complex clinical scenarios and patient-specific anatomies. While these models offer significant advantages, they lack the complexity of biological systems found in animal models. Conclusion: In conclusion, both animal and non-animal simulation models play crucial roles in enhancing surgical education, particularly in fetal and neonatal surgery. While advancements in non-animal technologies are important for ethical reasons, the continued necessity of animal models in certain areas should be acknowledged. By responsibly integrating these models into training programs, surgical education can be further enriched while upholding ethical standards and ensuring optimal patient outcomes.

Surgical Stone Trends from 2013 to 2021 in the US Medicare Population: Before and after the COVID-19 Pandemic.

Introduction and Objective: In early 2020, as the SARS-Cov-2 (COVID-19) pandemic progressed, many institutions limited nonurgent surgical care. This coincided with a decade-long trend of increasing percutaneous nephrolithotomy (PCNL) and ureteroscopy (URS) and decreasing shock wave lithotripsy (SWL) for surgical management of urolithiasis. Herein, we evaluate temporal stone surgery rates and surgeon volumes in the Medicare population and suggest how COVID-19 contributed to them. Methods: Retrospective analysis was conducted using the "Medicare Physician & Other Practitioners" database containing data from January 2013 to December 2021. Adult patients who underwent stone surgery were included. We evaluated surgeon characteristics and changes in case volumes over time adjusted for population. Results: In 2013, urologists performed 68,910 stone surgeries: SWL 42,903 (62%); URS 25,321 (37%); PCNL 686 (1%). Over the next 8 years, there was an average annual increase in URS (+13%) and PCNL (+13%) and decrease in SWL (-2%). In 2020, there was a 14% reduction in all stone cases: SWL (-25%); URS (-6%); PCNL (-8%). By 2021, case volumes recovered to pre-2020 levels, though SWL remained low: SWL 33,974 (34%); URS 64,541 (64%); PCNL 1764 (2%). From 2013 to 2021, the number of urologists performing SWL decreased (1718 to 1361) while URS and PCNL providers doubled (1,347 to 2,914 and 28 to 76, respectively). Conclusions: From 2013 to 2021, there was an increase in URS and PCNL and a decrease in SWL in the US Medicare population. The COVID-19 pandemic was associated with a decline in stone surgeries, particularly SWL. By 2021, PCNL and URS case numbers increased significantly with a smaller increase in SWL.

Diagnosis and management of primary hyperoxalurias: best practices.

The primary hyperoxalurias (PH 1, 2, and 3) are rare autosomal recessive disorders of glyoxylate metabolism resulting in hepatic overproduction of oxalate. Clinical presentations that should prompt consideration of PH include kidney stones, nephrocalcinosis, and kidney failure of unknown etiology, especially with echogenic kidneys on ultrasound. PH1 is the most common and severe of the primary hyperoxalurias with a high incidence of kidney failure as early as infancy. Until the recent availability of a novel RNA interference (RNAi) agent, PH care was largely supportive of eventual need for kidney/liver transplantation in PH1 and PH2. Together with the Oxalosis and Hyperoxaluria Foundation, the authors developed a diagnostic algorithm for PH1 and in this report outline best clinical practices related to its early diagnosis, supportive treatment, and long-term management, including the use of the novel RNAi. PH1-focused approaches to dialysis and kidney/liver transplantation for PH patients with progression to chronic kidney disease/kidney failure and systemic oxalosis are suggested. Therapeutic advances for this devastating disease heighten the importance of early diagnosis and informed treatment.

Higher Risk of Repeat Stone Surgery in Stone Formers With Concomitant Bowel Disease: Single-Center Long-Term Analysis.

OBJECTIVE: To identify the need for repeat stone surgery in patients with and without bowel disease. Few studies have compared risks between different types of bowel disease and whether their need for repeat stone surgery differs. METHODS: From our IRB-approved study, we identified patients with and without bowel disease. We categorized patients' bowel disease into 4 categories: inflammatory bowel disease (IBD), bypass procedures, bowel resection, and bowel disease not otherwise specified (eg, irritable bowel syndrome, celiac disease). Differences between patient demographics, stone disease, and recurrent stone events for patients with and without bowel disease were compared using univariate and multivariate survival analyses (SPSS 25). RESULTS: Of all surgical stone patients (2011), 484 (24%) had some type of bowel disease. Compared to patients without bowel disease, patients with bowel disease presented with stones at an older age (62.2 ± 14.5 vs 58.4 ± 15.3 years; P <.001) and were more likely to be female (56 vs 46%; P <.001). Patients with bowel disease required more repeat stone surgery than those without bowel disease (31% vs 23%, P <.001). In multivariate analysis, patients with bypass and bowel resection were associated with more repeat surgery than patients without bowel disease (P <.001, P = .002, respectively). Patients with IBD and bowel disease not otherwise specified did not have higher risk for repeat surgery than patients without bowel disease. CONCLUSION: Surgical stone patients with bowel disease, specifically those with prior bowel resection and bypass, had a higher risk of repeat stone surgery over time than stone formers without bowel disease. DATA AVAILABILITY: The data sets generated and analyzed during the current study are available from the corresponding author on reasonable request.

Deficient butyrate metabolism in the intestinal microbiome is a potential risk factor for recurrent kidney stone disease.

Intestinal microbiome dysbiosis is a known risk factor for recurrent kidney stone disease (KSD) with prior data suggesting a role for dysfunctional metabolic pathways other than those directly utilizing oxalate. To identify alternative mechanisms, the current study analyzed differences in the metabolic potential of intestinal microbiomes of patients (n = 17) and live-in controls (n = 17) and determined their relevance to increased risk for KSD using shotgun metagenomic sequencing. We found no differences in the abundance of genes associated with known oxalate degradation pathways, supporting the notion that dysfunction in other metabolic pathways plays a role in KSD. Further analysis showed decreased abundance of key enzymes involved in butyrate biosynthesis in patient intestinal microbiomes. Furthermore, de novo construction of microbial genomes showed that the majority of genes significantly enriched in non-stone formers are affiliated with Faecalibacterium prausnitzii, a major butyrate producer. Specifically pertaining to butyrate metabolism, the majority of abundant genes mapped back to F. prausnitzii, Alistipes spp., and Akkermansia muciniphila. No differences were observed in ascorbate or glyoxylate metabolic pathways. Collectively, these data suggest that impaired bacterial-associated butyrate metabolism may be an oxalate-independent mechanism that contributes to an increased risk for recurrent KSD. This indicates that the role of the intestinal microbiome in recurrent KSD is multi-factorial, which is representative of the highly intertwined metabolic nature of this complex environment. Future bacteria-based treatments must not be restricted to targeting only oxalate metabolism.

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.

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.

Development and Preliminary Validation of the 6-Item Short Form of the Wisconsin Stone Quality of Life Questionnaire.

OBJECTIVE: To develop a short form of the Wisconsin Stone Quality of Life (WISQOL): 1) identify the smallest subset of items from WSIQOL that accurately predict patients' health-related quality of life (HRQOL), and 2) in a clinical patient population, test these items-grouped together to form the WISQOL-short form (SF) - and assess its convergent validity. MATERIALS AND METHODS: The items for the WISQOL-SF were identified based on classic item analysis theory. Patients who previously completed the original 28-item WISQOL were randomly split into 2 groups of equal size. Scores for the WISQOL were calculated for one group while those for the WISQOL-SF were calculated for the other. Cronbach's alpha coefficients were calculated. Impacts of demographic and clinical factors as well as stone and symptom status at the time of WISQOL completion were examined. RESULTS: Patients (n = 740) who completed the WISQOL between 6/2017 and 11/2021 were included. Patients were 48% male, 54.1 ± 14.6 years old, and had a BMI of 31.2 ± 8.1. After item analysis and reduction, the six items ultimately included in the WISQOL-SF represented 2 of the 4 domains (social and emotional) of the original WISQOL. The internal consistency of the WISQOL-SF was similar to the original (Cronbach's alpha 0.943 vs. 0.973). No differences for health-related quality of life were found between groups (P = .567). CONCLUSION: The WISQOL-SF demonstrated the expected differences for gender and between patients with and without stone-related symptoms at the time of WISQOL completion. The WISQOL-SF showed good consistency and produced similar HRQOL scores to the full-form WISQOL.

Evaluation of a clinical and translational research initiative: Developing and implementing a collaborative evaluation process in CAIRIBU.

Funding for large research initiatives, such as those funded through the National Institutes of Health U mechanism, has increased since 2010; however, there is little published research on how to evaluate the success of such initiatives. Here, we describe the collaborative evaluation planning process undertaken by the Interactions Core of the Collaborating for the Advancement of Interdisciplinary Research in Benign Urology (CAIRIBU) research community, a clinical and translational research initiative funded by the National Institute of Diabetes and Digestive and Kidney Diseases. Evaluation is necessary to measure the impact of our work and to allow for continuous improvement efforts of CAIRIBU activities and initiatives. We developed and implemented an iterative seven-step process that engaged the Interactions Core, NIDDK program staff, and grantees at each step of the planning process. Challenges faced in planning and implementing the evaluation plan included the time burden on investigators to submit new data for evaluations, finite time and resources for evaluation work, and the development of infrastructure for the evaluation plan. We call on funding agencies to include more explicit requirements for evaluation participation from grantees, as well as dedicated funding to support the evaluation process, in future funding opportunity announcements for large research consortia.

Translation and validation of the Italian version of the Wisconsin Stone Quality of Life Questionnaire (I-WISQOL) for assessing quality of life in patients with urolithiasis.

BACKGROUND: Urolithiasis is a chronic condition, and it has been associated with a significant negative impact on patients' health-related quality of life (HRQOL). Several tools to assess patients' HRQOL have been validated in Italian, however disease-specific HRQOL instruments are still lacking. We aimed to develop and validate the Italian version of the WISQOL (I-WISQOL) in patients with urolithiasis. METHODS: The Italian version of the WISQOL was developed in a multistep process involving primary translation, back-translation, and pilot testing among a group of patients (N.=10). Patients presenting with urolithiasis were prospectively recruited from the outpatient stone clinics and completed both questionnaire WISQOL and SF-36. Demographic information, as well as medical and surgical data, were obtained through an interview. Internal consistency of the I-WISQOL was obtained with Cronbach's α. Correlation of total scores of the I-WISQOL and SF36 was assessed to determine convergent validity using Spearman Rho. Correlations between clinical variables and results from the I-WISQOL were analyzed to descriptively assess the association of interest. RESULTS: A total of 93 participants were evaluated and completed the Italian version of the I-WISQOL. The I-WISQOL demonstrated excellent internal consistency (Cronbach's α 0.95) and good convergent validity with the validated SF-36 (Spearman Rho r=0.70, P<0.001). Using ANOVA analysis, a significant decline in WISQOL Score was noted with the increasing number of renal colics (P=0.0543), ER visits (P=0.037), number of inpatient hospitalization (P=0.025). At multivariate analysis, worse WISQOL total score was predicted by a greater number of renal colic events (ß=-4.92 [-8.81-1.04], P=0.014) and by a greater number inpatient hospitalization (ß=-7.31 [-14.35 -0.26], P=0.042). CONCLUSIONS: The I-WISQOL is an internally consistent and valid instrument to assess HRQOL in Italian-speaking patients with kidney stones. Its use in clinical practice should be implemented in order to tailor the management of each patient.

Health-related quality of life disparities among Hispanic/Latinx patients with nephrolithiasis.

It is documented that Hispanic/Latinx kidney stone formers have inferior health-related quality of life (HRQoL) compared to the general population. We hypothesized that socioeconomic factors drive HRQoL disparities. Specifically, we sought to determine if medical insurance type is associated with HRQoL disparities among Hispanic/Latinx stone formers. This was a prospective cohort observational study of patients with kidney stones across the University of San Diego Health Care System. Patients enrolled from June 2018 to August 2020 completed a validated Wisconsin Stone Quality of Life questionnaire (WISQoL). Patient characteristics and self-reported HRQoL were compared between Hispanic/Latinx and non-Hispanic/Latinx stone formers using MANCOVA and ordinal logistic regression. Matched group comparisons were performed based on age, gender, body mass index, stone symptoms, and insurance type using MACOVA. A total of 270 patients were enrolled (Hispanic/Latinx n = 88; non-Hispanic/Latinx n = 182). Hispanic/Latinx stone formers had higher rates of public insurance at baseline (p < 0.001) with significantly lower HRQoL [social impact (p = 0.007)]. However, a matched cohort comparison demonstrated no differences. On multivariate analysis, private insurance increased the likelihood of having higher HRQoL (OR 2.21, p = 0.021), while stone symptoms (OR = 0.06, p < 0.001) and emergency department visits (OR = 0.04, p = 0.008) decreased chances of higher HRQoL. Ethnicity was not a significant factor in HRQoL scores on multivariate analysis. Our analysis suggests that differences in HRQoL among Hispanic/Latinx stone formers may be primarily driven by socioeconomic factors as opposed to clinical or racial differences. Specifically, source of insurance appears to have significant effect on HRQoL in this ethnic group.

Pulse-modulated Holmium:YAG Laser vs the Thulium Fiber Laser for Renal and Ureteral Stones: A Single-center Prospective Randomized Clinical Trial.

PURPOSE: We sought to compare the clinical effectiveness of the pulse-modulated Ho:YAG (holmium:yttrium-aluminum-garnet) laser and the thulium laser fiber for ureteroscopic stone management in a randomized clinical trial. The primary outcome was the ureteroscope time required to adequately fragment stones to 1 mm or less. Secondary outcomes were stone-free rate, complications, subjective surgeon measurement of laser performance, patient related stone quality of life outcomes, and measurements of laser efficiency. MATERIALS AND METHODS: An Institutional Review Board-approved randomized clinical trial was conducted to randomize patients to outpatient treatment with either the Moses 2.0 or thulium laser fiber in a 1:1 manner after stratification into groups based on the maximal diameter of treated stone (3-9.9 mm or 10-20 mm). Patient, stone, and operative parameters were compared using the appropriate categorical/continuous and parametric/nonparametric statistical tests (SPSS 25). RESULTS: From July 16, 2021 to March 11, 2022, 108 patients were randomized and had primary endpoint data available for analysis; 52 patients were randomized to Ho:YAG and 56 patients to thulium laser fiber. Groups were well balanced with no significant differences observed for patient or stone characteristics. Ureteroscope time was not significantly different between modalities (Ho:YAG mean 21.4 minutes vs thulium laser fiber mean 19.9 minutes, P = .60), or within subgroup analysis by stone size, median Hounsfield units, or stone location. There were no significant differences observed in the stone-free rate and complications rate between the 2 lasers. CONCLUSIONS: This randomized clinical trial suggests no significant clinical advantage of one laser technology over the other. Surgeon and institutional preference are the best approach when selecting one or the other.

Primary Contributors to Dietary Acid Load in Patients With Urolithiasis.

OBJECTIVES: In susceptible individuals, high dietary acid load may contribute to the formation of certain types of kidney stones via lowering urine pH and citrate excretion. The objective of this study is to determine the contribution of dietary acid from food groups in people with urolithiasis. DESIGN AND METHODS: Patients with calcium urolithiasis (n = 83) who completed food records were used for this retrospective analysis. Descriptive statistics were calculated for nutrients, potential renal acid load (PRAL), and estimated net endogenous acid production (NEAPest). Pearson's correlations were calculated between PRAL and NEAPest with each nutrient. RESULTS: Data from a total of 83 patients were used. Average PRAL was positively correlated with energy (r = 0.260, P = .02), total protein (r = 0.463, P < .001), animal protein (r = 0.555, P < .001), total fat (P = .399, P < .001), sodium (r = 0.385, P < .001), and phosphorus (r = 0.345, P < .001) intake. PRAL was negatively correlated with fiber (r = -0.246, P = .03) intake. NEAPest was positively correlated with total protein (r = 0.269, P = .01), animal protein (r = 0.377, P < .001), fat (r = 0.222, P = .04), and sodium (r = 0.250, P = .02) intake. NEAPest was negatively correlated with fiber (r = -0.399, P < .001), potassium (r = -0.360, P < .001), and magnesium (r = -0.233, P = .03) intake. For PRAL, meat contributed the highest acid load (52.7%), followed by grains (19.6%) and combination foods (19.6%). Beverages contributed the greatest alkali load (35.1%), followed by vegetables (30.6%) and fruits (28.6%). For NEAPest, cheese contributed the highest acid load (21.8%), followed by grains (19.3%) and meat (18.1%). CONCLUSIONS: For individuals with urolithiasis promoted by acidic urine and/or low urine citrate, dietary patterns with a high dietary acid load may contribute to recurrence risk. Meat and grains were the major contributors to dietary acid load in this cohort of patients with a history of kidney stones, whereas beverages, fruits, and vegetables contributed net alkali.

Ureteroscopy and Shock Wave Lithotripsy Trends from 2012 to 2019 Within the US Medicare Dataset: Sharp Growth in Ureteroscopy Utilization.

Introduction and Objective: Both ureteroscopy (URS) and shock wave lithotripsy (SWL) are cornerstones in the surgical management of urolithiasis in the United States. We hypothesized that URS utilization outpaced SWL utilization in recent years and quantified the magnitude of change over time for caseloads of URS and SWL among urologists from a national Medicare database. Methods: Using the public "Medicare Physician & Other Practitioners" database (https://data.cms.gov), we determined case numbers of SWL (current procedural terminology [CPT] 50590) and URS (CPT 52356 or 52353) from 2012 to 2019. In a subanalysis, we identified "high-volume stone urologists" as those in the upper quartile of case numbers for both SWL and URS in baseline years of either 2012 or 2013 and trended their caseload from 2012 to 2019. Linear estimation models assessed annual rates of change and their statistical significance. Results: In 2012, urologists performed 41,135 SWL procedures vs 21,184 URS. URS overtook SWL in 2017 and by 2019 was the dominant modality (60,063 URS vs 43,635 SWL). Between 2012 and 2019, total URS cases annually increased by 5700 (15%/year, p < 0.001), while the number of SWL cases peaked in 2015 and has since declined on average -1.6%/year (p = 0.020). The number of urologists performing URS steadily rose from 1147 in 2012 to 2809 in 2019, reflecting an additional 246 urologists (21%/year) performing URS annually. The caseload of high-volume stone urologists showed similar trends with average URS cases increasing by 2.9/year/urologist (9.8%/year, p < 0.001) and average SWL cases declining by 0.9/year/urologist (-1.7%/year, p = 0.023). Conclusions: URS utilization has increased dramatically and outpaced SWL utilization from 2012 to 2019 within the Medicare population. URS was increasingly used by both the general urologist population and high-volume stone urologists while SWL utilization has begun to decline.

International Alliance of Urolithiasis (IAU) guidelines on the metabolic evaluation and medical management of urolithiasis.

The aim of this study was to construct the fourth in a series of guidelines on the treatment of urolithiasis by the International Alliance of Urolithiasis (IAU) that by providing a clinical framework for the metabolic evaluation, prevention, and follow-up of patients with urolithiasis based on the best available published literature. All recommendations were summarized following a systematic review and assessment of the literature in the PubMed database from January 1976 to June 2022. Each generated recommendation was graded using a modified GRADE methodology. Guideline recommendations were developed that addressed the following topics: initial evaluation, metabolic testing, dietary measures, medical management, and follow-up of recurrent stone formers. It was emphasized by the Panel that prevention of new stone formation is as important as the surgical removal of the stones. Although general preventive measures may be effective in reducing stone recurrence rates in some patients, specific medical and dietary management should be well considered and eventually applied in an individualized manner based on the outcomes of metabolic work-up, stone analysis and some certain patient related factors. A detailed follow-up of each case is essential depending on the metabolic activity of each individual patient.

Mechanisms of the intestinal and urinary microbiome in kidney stone disease.

Kidney stone disease affects ~10% of the global population and the incidence continues to rise owing to the associated global increase in the incidence of medical conditions associated with kidney stone disease including, for example, those comprising the metabolic syndrome. Considering that the intestinal microbiome has a substantial influence on host metabolism, that evidence has suggested that the intestinal microbiome might have a role in maintaining oxalate homeostasis and kidney stone disease is unsurprising. In addition, the discovery that urine is not sterile but, like other sites of the human body, harbours commensal bacterial species that collectively form a urinary microbiome, is an additional factor that might influence the induction of crystal formation and stone growth directly in the kidney. Collectively, the microbiomes of the host could influence kidney stone disease at multiple levels, including intestinal oxalate absorption and direct crystal formation in the kidneys.

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.