Climate change and kidney stones

Economic Burden of Imaging and Interventions in Endourology: A Worldwide Cost Analysis from European Association of Urology Young Academic Urology Endourology and Urolithiasis Working Party

Background and Objective: The cost of imaging and interventions in the surgical field varies between countries and sometimes within different regions of the same country. Procedural cost takes into account equipment, consumables, operating room, surgical, anesthetic and nursing teams, radiology, medications, and hospital stay. Health care systems therefore face an incredible burden related to investigations and surgical procedures. The aim of this study was to collect costs of imaging and interventions for kidney calculi across different hospitals and health care systems in the world. Methods: An online shared Google spreadsheet was created by the European Association of Urology Young Academic Urology urolithiasis group. The survey consisted of the cost of four radiological imaging (ultrasound of the urinary tract [USS], plain X-ray radiography of the abdomen including kidneys, ureter, and bladder [XRKUB], noncontrast-enhanced computerized tomography [CTKUB], and contrast-enhanced CT with urographic phase [CTU]) and seven interventions (endoscopic laser treatment of renal stones, ureteroscopic treatment or extraction of ureteral stones, percutaneous nephrolithotomy (PCNL), insertion of ureteral stent, diagnostic ureteroscopy, and cystolitholapaxy). A chosen representative from each country collected and collated the data, and this was converted to Euros (€). Key Findings and Limitations: Data were collected from 32 countries, which include Turkey, Armenia, Nepal, Uzbekistan, Brazil, Chile, Qatar, Peru, Israel, Singapore, Thailand, Colombia, Argentina, Saudi Arabia, Asia, North America, 15 countries from the European continent, and the United States. The mean cost of USS, XRKUB, CTKUB, and CTU was 51.3 € (range: 2-160 €), 27.1 € (range: 2.5-187 €), 105.8 € (range: 19-405 €), and 171.5 € (range: 19-674 €), respectively. Similarly, the cost of endoscopic laser treatment of renal stones, ureteroscopic treatment/extraction of ureteral stones, PCNL, insertion of ureteral stent, diagnostic ureteroscopy, and cystolitholapaxy was 1942.6 € (range: 100-7887 €), 1626.8 € (range: 80-9787 €), 2884.6 € (range: 110-12642 €), 631 € (range: 110-2787 €), 861.6 € (range: 3-2667 €), and 876 € (range: 19-3457 €), respectively. Wide differences in cost between countries were found within the study. Conclusions and Clinical Implications: This study highlights the significant economic impact of kidney stone management on health care systems worldwide. There seem to be significant disparities between costs, and this study shows the social and economic inequalities in health care access, which can differ significantly between private and public health care. These results can aid policymakers to address these disparities and perhaps to learn from other health care providers.

Higher dietary insulin index is directly associated with the odd of kidney stones

Kidney stones or Nephrolithiasis are the most common health condition associated with the urinary system. Dietary factors stand as important factors in the occurrence and development of kidney stones. This study aimed to examine the potential link between dietary insulin index (DII) and dietary insulin load (DIL) with prevalence of kidney stones. This cross-sectional study was conducted among adults aged 30 to 75 years in the Shahedieh district of Yazd, Iran, over the period of 2015-2016. DII and DIL were calculated using a validated semi-quantitative food-frequency questionnaire and mathematical formula. Diagnosis of kidney stones is made on the basis of information obtained from self-reported questionnaire (Yes/ No). To explore the association between DII and DIL with the odds of kidney stones, logistic regression was employed in crude and adjusted models. A total of 4,829 participants were included in this study. Individuals in the last quartile of DIL had 214% higher odds of kidney stones in the crude model (OR: 2.14, 95% CI: 1.62-2.83; P-trend < 0.001); this association was remained significant after adjustments for confounding variables (OR: 1.44, 95% CI: 1.04-1.97; P-trend: 0.019). There was a direct significant relationship between DII and odds of kidney stones among third and forth quartiles of DII (OR: 1.52, 95% CI: 1.16-1.98, P-trend = 0.002); but this association disappeared for adjusted models. Higher DII and DIL were associated with an increased odd of renal stones. Large longitudinal study is required to clarify these associations.

New insight into oxidative stress and inflammatory responses to kidney stones: Potential therapeutic strategies with natural active ingredients

Kidney stones, a prevalent urological disorder, are closely associated with oxidative stress (OS) and the inflammatory response. Recent research in the field of kidney stone treatment has indicated the potential of natural active ingredients to modulate OS targets and the inflammatory response in kidney stones. Oxidative stress can occur through various pathways, increasing the risk of stone formation, while the inflammatory response generated during kidney stone formation further exacerbates OS, forming a detrimental cycle. Both antioxidant systems related to OS and inflammatory mediators associated with inflammation play roles in the pathogenesis of kidney stones. Natural active ingredients, abundant in resources and possessing antioxidative and anti-inflammatory properties, have the ability to decrease the risk of stone formation and improve prognosis by reducing OS and suppressing pro-inflammatory cytokine expression or pathways. Currently, numerous developed natural active ingredients have been clinically applied and demonstrated satisfactory therapeutic efficacy. This review aims to provide novel insights into OS and inflammation targets in kidney stones as well as summarize research progress on potential therapeutic strategies involving natural active ingredients. Future studies should delve deeper into exploring efficacy and mechanisms of action of diverse natural active ingredients, proposing innovative treatment strategies for kidney stones, and continuously uncovering their potential applications.

Influence of Dietary Heritage in a Restricted Geographic Area and Role of Food Additives on Risk of Recurrent Kidney Stone

Dietary factors may be implicated in the formation of kidney stones and should be closely monitored. To achieve this aim, patients are routinely assessed by means of generic dietary recall, a tool widely used by authors in a range of extensive patient populations to record food intake; the findings obtained, however, may be skewed due to dietary variations and underestimation of the effect of food additives. Fifty Frequent Kidney Stone Formers (FKSFs, mean age: 54.3 ± 13.9 years) with normal kidney function, absence of comorbidities, and reliable compliance were selected from a total of 68 patients' resident in Sardinia, an Italian island where genetic admixtures have been relatively rare for generations. The study, conducted from 1 January 2020 to 31 December 2023, was aimed at assessing nutritional values based on the meticulous recording of food quantities, quality, and potential modifications related to food preparation. Patients were selected during an initial clinical check-up and all efforts made to ensure they were capable of reliably recording all food and drinks consumed. A seven-day food diary was provided in which food and drink intake and their impact on 24 h urine output was recorded. The following parameters were measured in both foods and urine output: citrates, oxalates, calcium, phosphorous, uric acid, proteins and nitrogen compounds, magnesium, sulfates, potassium, carbohydrates, free fatty acids. Study outcomes established the presence of hypocitraturia, hyperoxaluria, hypercalciuria, and moderately high levels of nitrogen compounds. Univariate analysis followed by multivariate analysis for further confirmation were performed and the following observations made. Citrate intake correlated with citraturia but did not promote oxaluria; calcium intake promoted onset of sulfaturia, azoturia, and ammoniuria, whilst magnesium correlated with magnesiuria but not with oxaluria, calciuria, phosphaturia, and azoturia; sulfate intake elicited onset of azoturia but not kaliuresis; potassium intake promoted oxaluria and protein intake resulted in onset of ammoniuria and azoturia. (A) The chemical composition of urine based on dietary intake is hard to predict without taking into account the presence of dietary and urinary interferents; (B) the geographic isolation of patients studied underlines the importance of epigenetics in maintaining a traditional dietary heritage. (C) Moreover, the widespread use of food additives should consistently be taken into account to ensure a correct diagnosis of FKSF and set up a valid treatment plan.

Management of urinary stones: state of the art and future perspectives by experts in stone disease

AIM

To present state of the art on the management of urinary stones from a panel of globally recognized urolithiasis experts who met during the Experts in Stone Disease Congress in Valencia in January 2024. Options of treatment: The surgical treatment modalities of renal and ureteral stones are well defined by the guidelines of international societies, although for some index cases more alternative options are possible. For 1.5 cm renal stones, both m-PCNL and RIRS have proven to be valid treatment alternatives with comparable stone-free rates. The m-PCNL has proven to be more cost effective and requires a shorter operative time, while the RIRS has demonstrated lower morbidity in terms of blood loss and shorter recovery times. SWL has proven to be less effective at least for lower calyceal stones but has the highest safety profile. For a 6mm obstructing stone of the pelviureteric junction (PUJ) stone, SWL should be the first choice for a stone less than 1 cm, due to less invasiveness and lower risk of complications although it has a lower stone free-rate. RIRS has advantages in certain conditions such as anticoagulant treatment, obesity, or body deformity. Technical issues of the surgical procedures for stone removal: In patients receiving antithrombotic therapy, SWL, PCN and open surgery are at elevated risk of hemorrhage or perinephric hematoma. URS, is associated with less morbidity in these cases. An individualized combined evaluation of risks of bleeding and thromboembolism should determine the perioperative thromboprophylactic strategy. Pre-interventional urine culture and antibiotic therapy are mandatory although UTI treatment is becoming more challenging due to increasing resistance to routinely applied antibiotics. The use of an intrarenal urine culture and stone culture is recommended to adapt antibiotic therapy in case of postoperative infectious complications. Measurements of temperature and pressure during RIRS are vital for ensuring patient safety and optimizing surgical outcomes although techniques of measurements and methods for data analysis are still to be refined. Ureteral stents were improved by the development of new biomaterials, new coatings, and new stent designs. Topics of current research are the development of drug eluting and bioresorbable stents. Complications of endoscopic treatment: PCNL is considered the most invasive surgical option. Fever and sepsis were observed in 11 and 0.5% and need for transfusion and embolization for bleeding in 7 and 0.4%. Major complications, as colonic, splenic, liver, gall bladder and bowel injuries are quite rare but are associated with significant morbidity. Ureteroscopy causes less complications, although some of them can be severe. They depend on high pressure in the urinary tract (sepsis or renal bleeding) or application of excessive force to the urinary tract (ureteral avulsion or stricture). Diagnostic work up:  Genetic testing consents the diagnosis of monogenetic conditions causing stones. It should be carried out in children and in selected adults. In adults, monogenetic diseases can be diagnosed by systematic genetic testing in no more than 4%, when cystinuria, APRT deficiency, and xanthinuria are excluded. A reliable stone analysis by infrared spectroscopy or X-ray diffraction is mandatory and should be associated to examination of the stone under a stereomicroscope. The analysis of digital images of stones by deep convolutional neural networks in dry laboratory or during endoscopic examination could allow the classification of stones based on their color and texture. Scanning electron microscopy (SEM) in association with energy dispersive spectrometry (EDS) is another fundamental research tool for the study of kidney stones. The combination of metagenomic analysis using Next Generation Sequencing (NGS) techniques and the enhanced quantitative urine culture (EQUC) protocol can be used to evaluate the urobiome of renal stone formers. Twenty-four hour urine analysis has a place during patient evaluation together with repeated measurements of urinary pH with a digital pH meter. Urinary supersaturation is the most comprehensive physicochemical risk factor employed in urolithiasis research. Urinary macromolecules can act as both promoters or inhibitors of stone formation depending on the chemical composition of urine in which they are operating. At the moment, there are no clinical applications of macromolecules in stone management or prophylaxis. Patients should be evaluated for the association with systemic pathologies.

PROPHYLAXIS

Personalized medicine and public health interventions are complementary to prevent stone recurrence. Personalized medicine addresses a small part of stone patients with a high risk of recurrence and systemic complications requiring specific dietary and pharmacological treatment to prevent stone recurrence and complications of associated systemic diseases. The more numerous subjects who form one or a few stones during their entire lifespan should be treated by modifications of diet and lifestyle. Primary prevention by public health interventions is advisable to reduce prevalence of stones in the general population. Renal stone formers at "high-risk" for recurrence need early diagnosis to start specific treatment. Stone analysis allows the identification of most "high-risk" patients forming non-calcium stones: infection stones (struvite), uric acid and urates, cystine and other rare stones (dihydroxyadenine, xanthine). Patients at "high-risk" forming calcium stones require a more difficult diagnosis by clinical and laboratory evaluation. Particularly, patients with cystinuria and primary hyperoxaluria should be actively searched.

FUTURE RESEARCH

Application of Artificial Intelligence are promising for automated identification of ureteral stones on CT imaging, prediction of stone composition and 24-hour urinary risk factors by demographics and clinical parameters, assessment of stone composition by evaluation of endoscopic images and prediction of outcomes of stone treatments. The synergy between urologists, nephrologists, and scientists in basic kidney stone research will enhance the depth and breadth of investigations, leading to a more comprehensive understanding of kidney stone formation.

Arterial pseudoaneurysm: a rare complication following laser lithotripsy-case series and literature review

OBJECTIVE

To perform a comprehensive narrative review that will examine the risk factors and treatment outcomes of arterial pseudoaneurysm following laser flexible ureteroscopy (F-URS).

METHODS

A retrospective case series and a review of literature was performed. Clinical records from three patients treated for postoperative arterial pseudoaneurysm from January of 2021 to November 2023 were identified. A comprehensive literature review was also performed. The MEDLINE and Scopus databases were searched. The analysis was made by a narrative synthesis.

RESULTS

Three cases of postoperative arterial pseudoaneurysm were included, one from our center, one from Dubai, UAE, and one from Barcelona. The literature review identified six case reports, two after endocorporeal laser lithotripsy with thulium fiber laser (TFL) and four with Ho:YAG laser. All cases, from our series and literature review, presented with macroscopic hematuria and used high-power laser settings. All cases were treated by selective embolization.

CONCLUSION

Ho:YAG or TFL lasers are both capable of causing arterial pseudoaneurysms following F-URS if high-power settings are used. Selective artery embolization continues to be the treatment of choice with good outcomes.

Climate crisis and nephrology: a review of climate change's impact on nephrology and how to combat it

Climate change is worsening with tangible effects on our healthcare system. This review aims to examine the repercussions of the climate change on nephrology and explore potential strategies to mitigate its impact. This review examines dialysis's environmental impact, resource recycling methods, and plant-based diets for kidney health. Recent research highlights the advantages of plant-based diets in managing and preventing chronic kidney disease (CKD) and its complications. Integrating these practices can significantly lessen the environmental impact of nephrology.

PURPOSE OF REVIEW

The aim of this study is to discuss the bidirectional relationship of climate change and kidney disease and the impact of nephrology on climate change and to discuss potential solutions.

RECENT FINDINGS

Each dialysis session consumes significant amounts of resource; reusing them will aid the environment. Plant-based diets slow renal disease and have a lower carbon footprint, making them ecologically friendly.

SUMMARY

Climate change is a growing threat to population health and healthcare. Rising temperatures raise the risk of kidney problems. Dialysis treatments also impact the environment through its high resource requirements while generating high volumes of waste and greenhouse gases. Opportunities exist to reduce the environmental impact of dialysis treatments. Plant-based diets serve to benefit both kidney disease and the environment.

Popular Diets and Kidney Stones

Popular diets often influence dietary patterns, which have different implications for kidney stone risk. Despite the wide variety of popular diets, some general principles can be gleaned from investigating their potential impact on nephrolithiasis. Plant-based diets, including Dietary Approaches to Stop Hypertension, Mediterranean, flexitarian, and vegetarian diets, may protect against nephrolithiasis when they consist largely of unprocessed plant foods, while carbohydrate-restricted diets (including high-protein diets and the ketogenic diet) may raise kidney stone risk. Patients should be advised to consume a diet rich in whole plants, particularly fruits and vegetables, and minimize their consumption of animal proteins. Accompanying fruits and vegetables that are higher in oxalate content with more water and some dairy intake may also be useful. (We address the oxalate content of fruits and vegetables further below). Calcium consumption is an important component of decreasing the risk of kidney stones, as higher dietary calcium from dairy or nondairy sources is independently associated with lower kidney stone risk. Patients should also be advised to be conscious of fat intake, as fat in the intestinal lumen may complex with calcium and therefore increase urinary oxalate excretion. Finally, patients should avoid consumption of processed foods, which often contain added fructose and high sodium content, two factors that increase kidney stone risk.