Maternal family history of urolithiasis is associated with earlier age of onset of stone disease.

PURPOSE: To evaluate the impact of detailed family history on the severity of disease and age of onset in patients with urolithiasis. METHODS: Prospectively collected data from a single institution between October 2015 and December 2020 were analyzed. Our primary endpoint was the number of patients experiencing at least one recurrent stone during the follow-up period. RESULTS: Of 1566 patients analyzed, 603 (39%) reported at least one family member with a history of stones. The percentage of patients experiencing at least one recurrent stone event was higher in patients with a family history of stones (38%) compared to those without a family history of stones (28%) over a median follow-up period of 8 months (p = 0.001). On multivariate analysis, the presence of any family history of urolithiasis increased risk of recurrent stone events (odds ratio [OR] 1.62, p < 0.001). The presence of both a first- and a second-degree relative with urolithiasis was associated with higher odds for a recurrent stone event (OR 2.17; p = 0.003) and a younger age of onset for stones, (OR 3.32; < 0.001). A maternal-side relative with stones conferred a higher odds ratio for younger age of first onset of stones (OR 2.93; p < 0.001). CONCLUSION: Any family history of kidney stone disease imparts an increased risk of recurrent stone event and an earlier age of onset for urolithiasis. The presence of both first- and second-degree relatives or a maternal-side relative with kidney stones may be a predictor for an earlier age of onset for urolithiasis.

Urological In-Flight Medical Events on Commercial Airlines.

PURPOSE: In-flight medical events are rare but may cause significant distress as access to care is limited. There is a paucity of data on in-flight urological medical events. We describe urological in-flight medical emergencies and report clinical and flight outcomes. MATERIALS AND METHODS: We reviewed all in-flight urological medical emergencies between 2015 and 2017 from MedAire®, a ground based medical support center that provides remote medical advisory services to approximately 35% of commercial airline passenger traffic worldwide. Our primary end point was the incidence rates of in-flight urological medical events. We also characterized the types of in-flight medical emergencies, in-flight management and their impact on flight status. Statistical analyses included Student's t-tests, chi-square analysis and analysis of variance. RESULTS: We identified 1,368 (1%) urological in-flight medical emergencies from a total of 138,612 in-flight medical emergencies, with an incidence of 0.5 per million passengers. The most common in-flight medical emergencies were lower urinary tract symptoms (35%), urinary retention (30%) and flank pain (21%). Among in-flight medical emergencies 883 (60%) resolved in flight, 273 (28%) required on-arrival medical evaluation and 21 (1.5%) resulted in flight diversions. Of the flight diversions the majority were due to urinary retention (12, 57%) and less commonly flank pain (6, 28%) and testicular/abdominal pain (3, 15%). CONCLUSIONS: The most common causes of urological in-flight medical emergencies are lower urinary tract symptoms, urinary retention and renal colic, the majority of which resolved in flight. These data are useful for informing flight personnel and emergency kit equipment needs to minimize the impact of these events when they occur.

A Phase I Trial of Intravesical Cabazitaxel, Gemcitabine and Cisplatin for the Treatment of Nonmuscle Invasive bacillus Calmette-Guérin Unresponsive or Recurrent/Relapsing Urothelial Carcinoma of the Bladder.

PURPOSE: For patients with bacillus Calmette-Guérin unresponsive or recurrent/relapsing nonmuscle invasive bladder cancer, multi-agent intravesical trials have been limited. In this study we investigate the safety of intravesical cabazitaxel, gemcitabine and cisplatin in the salvage setting. MATERIALS AND METHODS: This was a dose escalation, drug escalation trial for patients with bacillus Calmette-Guérin unresponsive or recurrent/relapsing nonmuscle invasive bladder cancer who declined or were ineligible for radical cystectomy. All patients underwent a 6-week induction regimen of sequentially administered cabazitaxel, gemcitabine and cisplatin. Complete response was defined as no cancer on post-induction transurethral bladder tumor resection and negative urine cytology, while partial response allowed for positive cytology. Responders continued with maintenance cabazitaxel and gemcitabine monthly for the first year and bimonthly for the second year. RESULTS: A total of 18 patients were enrolled. Mean age was 71 years, median followup was 27.8 months (range 16.3 to 46.9) and mean number of previous rounds of intravesical therapies before trial enrollment was 3.7. Nine patients (50%) had received intravesical chemotherapy after bacillus Calmette-Guérin and 7 (39%) were previously treated in a phase I clinical trial setting. At enrollment 6 (33%) subjects had T1 disease and 13 (72%) had carcinoma in situ. There were no dose limiting toxicities. Initial partial and complete response rates were 94% and 89%, respectively. At 1 year recurrence-free survival was 0.83 (range 0.57 to 0.94) and at 2 years estimated recurrence-free survival was 0.64 (0.32 to 0.84). CONCLUSIONS: In this high risk and highly pretreated cohort of bacillus Calmette-Guérin unresponsive or recurrent/relapsing nonmuscle invasive bladder cancer cases combination intravesical cabazitaxel, gemcitabine and cisplatin was a well tolerated and potentially effective regimen.

Linking 24-h urines to clinical phenotypes: what alternatives does the future bring?

PURPOSE OF REVIEW: The 24-h urine test is recommended as part of the metabolic evaluation for patients with nephrolithiasis to guide preventive interventions. However, this test may be challenging to interpret and has limits in its predictive ability. In this review, we summarize and discuss the most recent research on the opportunities and challenges for utilizing urinary biomarkers for kidney stone prevention. RECENT FINDINGS: Contemporary studies utilizing the 24-h urine test have improved our understanding of how to better administer testing and interpret test results. Beyond the standard panel of 24-h urine parameters, recent applications of proteomics and metabolomics have identified protein and metabolic profiles of stone formers. These profiles can be assayed in future studies as potential biomarkers for risk stratification and prediction. Broad collaborative efforts to create large datasets and biobanks from kidney stone formers will be invaluable for kidney stone research. SUMMARY: Recent advances in our understanding of kidney stone risk have opened opportunities to improve metabolic testing for kidney stone formers. These strategies do not appear to be mutually exclusive of 24-h urine testing but instead complementary in their approach. Finally, large clinical datasets hold promise to be leveraged to identify new avenues for stone prevention.

Assessment of practices in screening and treating women with bacteriuria.

INTRODUCTION: Evidence-based screening and treatment for bacteriuria is crucial to prevent increasing antibiotic resistance. The Infectious Disease Society of America (IDSA) previously released guidelines on the management of asymptomatic bacteriuria (ASB) and uncomplicated urinary tract infections (UTIs) in women. The study's objective was to assess physicians' practices in managing women with bacteriuria relative to these guideline recommendations. MATERIALS AND METHODS: Cross-sectional data from physicians were collected using an anonymous questionnaire. Multivariable logistic regression analyses identified independent predictors of adherence to guidelines. RESULTS: Data were collected from 260 physicians. Over half of physicians surveyed were unfamiliar with IDSA guidelines and overtreat ASB. Variables independently associated with overtreatment of ASB included a non-academic practice and practicing as an OBGYN. Nearly one third (30.1%) of physicians reported prescribing an antibiotic other than a recommended first-line agent for uncomplicated cystitis. Relative to internists, OBGYNs and urologists were more likely to prescribe a recommended first-line agent to women with uncomplicated cystitis. Of those who correctly selected a first-line agent, 29.8% prescribed a longer than recommended duration of therapy. IDSA guideline awareness was not associated with physicians' practices in managing women with bacteriuria. CONCLUSIONS: Most physicians surveyed were unfamiliar with guidelines related to managing ASB and uncomplicated UTIs in women, likely contributing to overscreening and overtreatment of ASB and the use of inappropriate antibiotic regimens in treating uncomplicated cystitis. However, optimal antibiotic prescribing was not associated with knowledge of IDSA guidelines, suggesting that guideline dissemination alone may not alter practice patterns among physicians managing women with bacteriuria.

Safety of Mesh for Vaginal Cystocele Repair: Analysis of National Patient Characteristics and Complications.

PURPOSE: The use of mesh in vaginal cystocele repair has decreased. We analyzed the ACS NSQIP® (American College of Surgeons National Surgical Quality Improvement Project) database to compare outcomes of repairs with and without mesh. MATERIALS AND METHODS: CPT was used to identify patients who underwent cystocele repair with and without mesh from 2006 to 2013. Patient characteristics and complications were analyzed. RESULTS: We identified 6,849 patients, of whom 5,667 (82.5%) underwent native tissue repair and 1,182 (17.5%) underwent repair with mesh. Patients who received mesh were older (mean ± SD age 64 ± 11 vs 60 ± 12 years, p <0.001) and more had comorbidities (56% vs 47%, p <0.001). Mean mesh vs nonmesh operative time (97 ± 67 vs 95 ± 53 minutes, p = 0.2) and mean length of stay (1.3 ± 2.4 vs 1.4 ± 1.3 days, p = 0.2) were similar in the 2 groups. Urinary tract infection was the most common complication in cases without vs with mesh (3.8% vs 3.5%). Mesh procedure rates of mortality (0% vs 0.3%, p = 0.04) and overall surgical complications (1.8% vs 3.9% p <0.001) were higher. On multivariate analysis ASA® class 3 or greater (OR 1.4, p = 0.01), longer operative time (OR 1.004, p <0.001) and mesh (OR 1.32, p = 0.05) were associated with greater morbidity. Patient comorbidities, surgeon specialty and concomitant procedures did not confer an increased risk of complications. CONCLUSIONS: Native tissue repair is performed more commonly than mesh repair. ASA class, operative time and mesh use are associated with an increased risk of postoperative morbidity. These results suggest an increased risk of complications when using mesh in vaginal anterior repair, although the overall risk in each procedure was low.

Sling Procedures for the Treatment of Stress Urinary Incontinence: Comparison of National Practice Patterns between Urologists and Gynecologists.

PURPOSE: Sling procedures, which have become the dominant method of surgical management of stress urinary incontinence, are frequently performed by urologists and gynecologists. Few studies investigating trends in surgical management have focused on differences in provision of care between the specialties. In this study we compared national practice patterns of sling procedures by provider type. MATERIALS AND METHODS: We analyzed the 2006 to 2013 ACS (American College of Surgeons) NSQIP (National Surgical Quality Improvement Program) database. CPT-4 codes were used to identify patients who underwent sling procedures and any concomitant pelvic floor procedures. Patient and operative characteristics were compared between urologists and gynecologists using bivariate and multivariate analysis. RESULTS: Our analytical cohort included 22,192 sling procedures, of which 5,718 (25.8%) and 16,474 (74.2%) were performed by urologists and gynecologists, respectively. Urologists performed a greater percent of autologous fascial sling procedures than gynecologists (1.16% vs 0.06%, p <0.001). Concomitant prolapse repair was performed in 8,664 patients (44.1%), including 954 (16.7%) of urologists and 7,710 (46.8%) of gynecologists. On multivariable analysis urology patients were less likely to undergo concomitant prolapse repair or hysterectomy. Urology patients were more likely to have hypertension and be older, have a higher ASA® (American Society of Anesthesiologists®) class and be current smokers. CONCLUSIONS: Gynecologists perform the majority of sling procedures for stress urinary incontinence. While gynecologists perform more concomitant procedures, urologists tend to operate on older patients with more comorbidities. Urologists also perform a greater proportion of autologous fascial sling procedures. These findings demonstrate that, although gynecologists perform a greater number of surgeries, urologists treat a unique population of patients who require operative management of stress urinary incontinence.

Impact of Surgeon Case Volume on Reoperation Rates after Inflatable Penile Prosthesis Surgery.

PURPOSE: We investigated the impact of surgeon annual case volume on reoperation rates after inflatable penile prosthesis surgery. MATERIALS AND METHODS: The New York Statewide Planning and Research Cooperative System database was queried for inflatable penile prosthesis cases from 1995 to 2014. Multivariate proportional hazards regression was performed to estimate the impact of surgeon annual case volume on inflatable penile prosthesis reoperation rates. We stratified our analysis by indication for reoperation to determine if surgeon volume had a similar effect on infectious and noninfectious complications. RESULTS: A total of 14,969 men underwent inflatable penile prosthesis insertion. Median followup was 95.1 months (range 0.5 to 226.7) from the time of implant. The rates of overall reoperation, reoperation for infection and reoperation for noninfectious complications were 6.4%, 2.5% and 3.9%, respectively. Implants placed by lower volume implanters were more likely to require reoperation for infection but not for noninfectious complications. Multivariable analysis demonstrated that compared with patients treated by surgeons in the highest quartile of annual case volume (more than 31 cases per year), patients treated by surgeons in the lowest (0 to 2 cases per year), second (3 to 7 cases per year) and third (8 to 31 cases per year) annual case volume quartiles were 2.5 (p <0.001), 2.4 (p <0.001) and 2.1 (p=0.01) times more likely to require reoperation for inflatable penile prosthesis infection, respectively. CONCLUSIONS: Patients treated by higher volume implanters are less likely to require reoperation after inflatable penile prosthesis insertion than those treated by lower volume surgeons. This trend appears to be driven by associations between surgeon volume and the risk of prosthesis infection.

Contemporary treatment patterns and outcomes of sarcomatoid bladder cancer.

PURPOSE: To characterize the treatment patterns and survival outcomes of sarcomatoid bladder cancer, a rare urothelial variant histology using a large population level cancer database. METHODS: The National Cancer Database was queried for all cases of sarcomatoid bladder cancer using International Classification of Disease-O-3 morphologic code 8122 between 2004 and 2014. Primary outcome was overall survival. RESULTS: A total of 489 patients met our inclusion criteria and were included in our analysis. Average age at diagnosis was 70.4 years. The majority of the population was male (61.8%) and Caucasian (92.2%). Tumor characteristics included 23.7% cT1, 41.1% cT2 and 15.3% cT3 or above. Median overall survival was 18.4 months (95% CI 13.3-23.6). On multivariate Cox proportional analysis, radical cystectomy alone or with multimodal therapy (chemotherapy or radiotherapy) resulted in a statistically significant reduction in the risk of death as compared to bladder preservation surgery alone. Survival in the radical cystectomy group did not differ between radical cystectomy alone and those receiving either neoadjuvant or adjuvant chemotherapy. CONCLUSIONS: Sarcomatoid bladder cancer has poor prognosis with 18.4-month median overall survival. While our data suggest that aggressive treatment improves outcomes, the role of multimodal therapy is unclear. Future study should continue to focus on multi-institutional collaboration to determine the most effective therapy.

Vesicovaginal fistulas in the developed world: An analysis of disease characteristics, treatments, and complications of surgical repair using the ACS-NSQIP database.

AIMS: To analyze patient characteristics, complications, and surgical trends in vesicovaginal fistulas (VVF) from a national database. METHODS: Current Procedural Terminology was used to identify patients undergoing VVF repair from the American College of Surgeons National Surgical Quality Improvement Project (NSQIP) database. Characteristics and treatments were identified. Logistic regression was used to identify characteristics associated with complications. RESULTS: From 2006 to 2013, 200 patients underwent VVF repair. Mean age was 50.3 ± 12.3 years. A large proportion of patients were overweight (72%) and recent smokers (30%). Predominant comorbidities were heart disease (29%) and type 2 diabetes (9.5%). Of all VVF repairs, 65% were repaired vaginally. Concomitant procedures included hysterectomy (n = 6), reconstructive flaps (n = 13), and slings (n = 2). Post-operative complications occurred in 15% of patients. The most common complication was urinary tract infection (8%) followed by blood transfusion (3%). Compared to the vaginal approach, abdominal VVF repairs had higher overall morbidity (22% vs 7% P = 0.003), longer length of stay (3.5 ± 2.3 vs 1.6 ± 2 days P = 0.00) and were more likely to be associated with sepsis (4.3% vs 0% P = 0.02), blood transfusion (7.1% vs 0.8% P = 0.017), and readmission (10.1% vs 0.8% P = 0.003). In multivariate analysis, abdominal approach was a significant predictor of complications within 30 days (P = 0.03, P = 0.02). CONCLUSIONS: In the US VVF remains a rare entity. Over half of VVFs were repaired vaginally. The occurrence of serious complications is low. A vaginal approach appears to be associated with fewer complications.

Risk Factors for Priapism Readmission.

INTRODUCTION: Priapism is a urologic emergency with a tendency to recur in some patients. The frequency of, time to, and risk factors for priapism recurrence have not been well characterized. AIM: To identify predictors of priapism readmission. METHODS: We used the New York Statewide Planning and Research Cooperative System database to identify patients presenting to emergency departments with priapism from 2005 through 2014. Patients were tracked up to 12 months after initial presentation. Proportional hazards regression was used to identify risk factors for priapism readmission. MAIN OUTCOME MEASURES: Readmissions for priapism. RESULTS: The analytic cohort included 3,372 men with a diagnosis of priapism. The average age at first presentation was 39 ± 18 years and 40% were black. Within 1 year, 24% of patients were readmitted for recurrent priapism, 68% of whom were readmitted within 60 days. On multivariate analysis, sickle cell disease (hazard ratio [HR] = 2.5, 95% CI = 2.0-3.0), drug abuse or psychiatric disease (HR = 1.9, 95% CI = 1.6-2.2), erectile dysfunction history (HR = 1.9, 95% CI = 1.5-2.3), other than commercial medical insurance (HR = 1.2, 95% CI = 1.0-1.4), and inpatient admission for initial priapism event (HR = 0.5, 95% CI = 0.4-0.6) were significant risk factors for readmission. CONCLUSION: Nearly one fourth of patients with priapism were readmitted for recurrent priapism within 1 year of initial presentation. Most readmissions were within 60 days. Future research should focus on strategies to decrease recurrences in high-risk patients.

Perioperative blood transfusion predicts short term morbidity after nephrectomy.

INTRODUCTION: To assess 30-day morbidity and mortality following partial nephrectomy (PN) and radical nephrectomy (RN) with relation to the administration of perioperative blood transfusions PBT). MATERIALS AND METHODS: The National Surgical Quality Improvement Program was queried for patients with malignant renal tumors (International Classification of Diseases Ninth Revision codes 189-189.2) who underwent RN (Current Procedure Terminology codes 50220, 50225, 50230, 50234, 50236, 50545, 50546, 50548) or PN (50240, 50543) between 2005-2013. Patients were stratified by transfusion status and assessed for postoperative outcomes both separately and in composite, including morbidity, mortality, infectious complications, and pulmonary complications. Univariate and multivariate analyses were performed to identify significant independent predictors of these composite outcomes. RESULTS: The overall transfusion rates were 15.8% and 8.2% for RN and PN, respectively. On multivariate analysis, PBT was associated with increased morbidity (RN: OR 2.147, 95% CI 1.687-2.733; PN: OR 2.081, 95% CI 1.434-3.022), mortality (RN: OR 2.308, 95% CI 1.159-4.598; PN: OR 5.166, 95% CI 1.207-22.12), infectious complications (RN: OR 1.656, 95% CI 1.151-2.383; PN: OR 1.945, 95% CI 1.128-3.354) and pulmonary complications (RN: OR 3.040, 95% CI 2.125-4.349; OR 3.771, 95% CI 2.108-6.746). CONCLUSIONS: For patients undergoing RN or PN there is a significant association between receipt of PBT and 30-day postoperative outcomes, specifically overall morbidity, mortality, infectious complications, and pulmonary complications. The mechanism that underlies these effects has not been elucidated, but it most likely involves immunomodulation and acute lung injury. Future research should focus on formulating comprehensive transfusion guidelines for oncologic-related nephrectomies.

Perioperative blood transfusion in radical cystectomy: Analysis of the National Surgical Quality Improvement Program database.

OBJECTIVES: To determine whether perioperative blood transfusion is associated with worse 30-day postoperative outcomes in radical cystectomy patients. METHODS: Utilizing the National Surgical Quality Improvement Program database, we identified 2934 patients diagnosed with bladder cancer (International Classification of Diseases Ninth Revision codes 188-188.9) who underwent radical cystectomy (Current Procedure Terminology codes 51570, 51575, 51580, 51585, 51590, 51595, 51596) between 2005 and 2013. Patients were stratified by transfusion status and assessed based on four composite postoperative outcomes: morbidity, surgical site infection, mortality and readmission. Multivariate regression models were used to determine significant independent predictors of the composite outcomes. RESULTS: Overall, 40.1% of patients received a transfusion, and there were significant differences in baseline variables such as age, sex, body mass index, smoking history and comorbidities. Transfusion was associated with increased morbidity, surgical site infection, readmission, operative time and length of stay on unadjusted analyses. On multivariate regression, transfusion was associated with increased morbidity (OR 1.361, 95% CI 1.131-1.638) and surgical site infection (OR 1.371, 95% CI 1.070-1.757). CONCLUSIONS: Perioperative blood transfusion is associated with increased risk of postoperative infection and morbidity. Previous work in this area has focused on negative long-term oncological outcomes, but this is the first study to examine short-term postoperative outcomes. Future research should focus on the immunosuppressive mechanism of perioperative blood transfusion and on restrictive transfusion guidelines for oncology patients.

Case presentation and review of renal autotransplantation for nutcracker syndrome.

Nutcracker Syndrome (NCS) is characterized by entrapment of the left renal vein, leading hematuria, flank pain, and proteinuria. We evaluated the efficacy of renal autotransplantation as a curative treatment for NCS through a review and case report. 55 patients from 18 studies were analyzed, with a combined 91% success rate of symptom resolution or improvement post-autotransplantation. In our case report, a 25-year-old man with severe NCS received laparoscopic nephrectomy and autotransplant, resulting in symptom resolution at 3.1 years follow up. Further research should confirm these findings and refine patient selection criteria and surgical techniques.

Renal autotransplantation: association between preoperative disease duration and surgical outcomes.

OBJECTIVE: To determine whether early vs. delayed autotransplantation are associated with adverse outcomes in patients undergoing renal autotransplantation. METHODS: Patients who underwent renal autotransplantation from June 2012 to September 2022 were divided into two groups based on timing of autotransplant in relation to initial intervention or diagnosis (early cohort: ≤1-year; delayed cohort: >1-year). Primary outcomes were perioperative complications, aborted surgery, renal function (glomerular filtration rate [GFR]), and postoperative complications at most recent follow-up. RESULTS: Autotransplantation patients (N=72) were predominantly female (68%) and White (54%), with a median age of 49 years. 90% of patients had undergone previous interventions, including stenting (40%) and nephrostomy tubes (49%), primarily for obstruction (64%). Early vs. delayed cohorts had median preoperative disease durations of 143 (IQR 83-222) vs. 673 days (IQR 529-1,703, p<0.001), with similar median follow-up times (879 vs. 818 days, p=0.8). Groups were similar in demographics and comorbidities. There were no significant differences in rates of aborted surgery (15% vs. 4.2%, p=0.3), perioperative complications (15% vs. 17%, p>0.9), long-term complications (49% vs. 48%, p>0.9), or changes in GFR (median change +3 vs. +4, p=0.7). Outcomes were comparable across preoperative disease durations ranging from 6 to 24 months. These findings were confirmed following adjustments for sex, body mass index, American Society of Anesthesiologists classification, race, preoperative creatinine levels, laterality, gastroesophageal reflux disease, diabetes, hypertension, nephrolithiasis, hyperlipidemia, history of colon surgery, urologic surgery, abdominal surgery, and prior interventions in separate logistic models. CONCLUSIONS: Disease duration before autotransplantation does not influence outcomes, offering reassurance for clinical decision-making in complex cases.

Association between obstructive sleep apnea and 24-h urine chemistry risk factors for urinary stone disease.

The effect of obstructive sleep apnea (OSA) on 24-h urine parameters and resultant kidney stone risk is unknown. We sought to compare urinary lithogenic risk factors among patients with kidney stone disease with and without OSA. We performed a retrospective cohort study of adult patients with nephrolithiasis undergoing both polysomnography and 24-h urine analysis. Measures of acid load including gastrointestinal alkali absorption, urinary titratable acid, and net acid excretion were calculated from 24-h urine. We performed univariable comparisons of 24-h urine parameters between those with and without OSA and fit a multivariable linear regression model adjusting for age, sex, and BMI. Overall, there were 127 patients who underwent both polysomnography and a 24-h urine analysis from 2006 to 2018. There were 109 (86%) patients with OSA and 18 (14%) without. Patients with OSA were more commonly male, had greater BMI and had higher rates of hypertension. Patients with OSA had significantly higher levels of 24-h urinary oxalate, uric acid, sodium, potassium, phosphorous, chloride, and sulfate; higher supersaturation of uric acid; higher titratable acid, and net acid excretion; and lower urinary pH and supersaturation of calcium phosphate (p < 0.05). The difference in urinary pH and titratable acid, but not net acid excretion, remained significant when adjusting for BMI, age, and gender (both p = 0.02). OSA is associated with changes in urinary analytes that promote kidney stone formation, similar to those observed with obesity. After accounting for BMI, OSA is independently associated with lower urine pH and increased urinary titratable acid.

Voided volume may not impact stone outcomes: Review of a large institutional nephrolithiasis cohort.

Background: Urologic guidelines universally recommend increasing fluid intake for kidney stone prevention. Increased voided volume is thought to help reduce stone recurrence and severity, but supporting evidence is limited. Patients and Methods: Nephrolithiasis outcomes and 24-h urine data for patients from the Registry for Stones of the Kidney and Ureter (ReSKU), a registry of nephrolithiasis patients collected between 2015 and 2020, were retrospectively analysed. Outcome was stone events, either an office visit where a patient reports symptomatic passage of stones or surgery for stone removal. Results: We identified 450 stone patients with 24-h urine and kidney stone outcome data. There was no significant difference in 24-h voided volume between patients with one stone event and patients with two or more stone events. On multivariable logistic regression, after controlling for age, gender, BMI, and 24-h sodium and creatinine per kilogram, no significant associations were found between voided volume and stone events. There was a statistically significant negative correlation noted between voided volume and stone events in calcium oxalate dihydrate stone formers (Spearman R = -0.42, p = 0.04), but not others. Conclusions: Twenty-four-hour voided volume was not associated with stone events in a large institutional cohort, and subset analysis reveals that some stone formers may benefit more from increased voided volume than others; identifying such patients represents a novel precision medicine opportunity.

Ultrasound-Only Percutaneous Nephrolithotomy Is Safe and Effective Compared to Fluoroscopy-Directed Percutaneous Nephrolithotomy.

Introduction: Outcomes after ultrasound-only percutaneous nephrolithotomy (PCNL), in which no fluoroscopy is used, are not well known. The goal of this study was to compare outcomes of ultrasound-only and fluoroscopy-directed PCNL. Materials and Methods: Prospectively collected data from the Registry for Stones of the Kidney and Ureter database were reviewed for all patients who underwent PCNL at one academic center from 2015 to 2021. Primary outcomes were complications and stone-free rates (no residual fragments ≥3 mm). Results: Of the 141 patients who underwent ultrasound-only PCNL and 147 who underwent fluoroscopy-directed PCNL, there was no difference in complication rates (15% vs 16%, p = 0.87) or stone-free status (71% vs 65%, p = 0.72), respectively. After adjusting for body mass index, American Society of Anesthesiologists (ASA), stone size, and stone complexity by Guy score, ultrasound-only PCNL was not associated with any increased odds of complications (odds ratio [OR] 0.7, 95% confidence interval [CI] 0.3-1.6, p = 0.41) or residual stone fragments ≥3 mm (OR 1.0, 95% CI 0.5-1.9, p = 0.972) compared with fluoroscopy-directed PCNL. Ultrasound-only PCNL was associated with shorter operative time (median 99.5 vs 126 minutes, p < 0.001), and the use of ultrasound remained a significant predictor of short operative time (<100 minutes) after controlling for supine positioning, stone size, and stone complexity by Guy score (OR 2.31, 95% CI 1.01-5.29, p = 0.048). Patients in the ultrasound-only group were spared a mean radiation exposure dose of 10 mGy per procedure. Conclusions: Ultrasound-only PCNL is safe and achieves similar stone-free rates compared with fluoroscopy-directed PCNL with the added benefit of avoidance of radiation.

Proton pump inhibitors use and risk of incident nephrolithiasis.

Proton pump inhibitors (PPIs) are widely prescribed medications that have effects on both enteric and urinary solute handling with an unknown effect on risk of nephrolithiasis. Our objectives were to examine the association between PPI exposure and incident nephrolithiasis and to determine its effect on 24H urine chemistry. We performed a single-center retrospective study on patients diagnosed with gastroesophageal reflux disease (GERD) without a history of kidney stones. Exposure to PPIs was abstracted, and then subsequent kidney stone diagnoses were identified. Multivariable Cox models with time-varying covariates were used to estimate the hazard of PPI use on incident nephrolithiasis. We used multivariable linear regression to analyze a subset of patients who went through 24-h urine analysis. We identified n = 55,765 PPI-naïve GERD patients without prior kidney stone diagnoses of whom 40,866 (73.2%) were exposed to PPI over a median of 3 year follow up. On multivariable analysis, PPI use was associated with higher risk of incident kidney stone diagnoses (HR 1.19, 95% CI 1.06-1.34). Among 593 patients with GERD with 24-H urine data, the PPI-exposed group (n = 307) had significantly lower mean urinary citrate (mean 3.0 vs 3.4 mmol, p = 0.029) and urinary magnesium (mean 3.6 vs 4.3 mmol, p < 0.001) on multivariable analyses. Exposure to PPIs is associated with an increased risk of kidney stones among patients with GERD. Hypomagnesemia and hypocitraturia associated with PPI exposure may contribute to kidney stone risk.

Machine Learning Models to Predict 24 Hour Urinary Abnormalities for Kidney Stone Disease.

OBJECTIVE: To help guide empiric therapy for kidney stone disease, we sought to demonstrate the feasibility of predicting 24-hour urine abnormalities using machine learning methods. METHODS: We trained a machine learning model (XGBoost [XG]) to predict 24-hour urine abnormalities from electronic health record-derived data (n = 1314). The machine learning model was compared to a logistic regression model [LR]. Additionally, an ensemble (EN) model combining both XG and LR models was evaluated as well. Models predicted binary 24-hour urine values for volume, sodium, oxalate, calcium, uric acid, and citrate; as well as a multiclass prediction of pH. We evaluated performance using area under the receiver operating curve (AUC-ROC) and identified predictors for each model. RESULTS: The XG model was able to discriminate 24-hour urine abnormalities with fair performance, comparable to LR. The XG model most accurately predicted abnormalities of urine volume (accuracy = 98%, AUC-ROC = 0.59), uric acid (69%, 0.73) and elevated urine sodium (71%, 0.79). The LR model outperformed the XG model alone in prediction of abnormalities of urinary pH (AUC-ROC of 0.66 vs 0.57) and citrate (0.69 vs 0.64). The EN model most accurately predicted abnormalities of oxalate (accuracy = 65%, ROC-AUC = 0.70) and citrate (65%, 0.69) with overall similar predictive performance to either XG or LR alone. Body mass index, age, and gender were the three most important features for training the models for all outcomes. CONCLUSION: Urine chemistry prediction for kidney stone disease appears to be feasible with machine learning methods. Further optimization of the performance could facilitate dietary or pharmacologic prevention.