Global, Regional, and National Burden of Urolithiasis from 1990 to 2019: A Systematic Analysis for the Global Burden of Disease Study 2019

Large-scale identification of calcium oxalate stone inhibitory proteins in normal human urine

Recent evidence has shown that proteins in normal human urine can inhibit calcium oxalate (CaOx) kidney stone formation. Herein, we performed fast protein liquid chromatography (FPLC) to fractionate normal human urinary proteins using anion-exchange (DEAE) and size-exclusion (Superdex 200) materials. FPLC fractions (F1-F15) were examined by CaOx crystallization, growth, aggregation and crystal-cell adhesion assays. The fractions with potent inhibitory activities against CaOx crystals were then subjected to mass spectrometric protein identification. The data revealed that 13 of 15 fractions showed inhibitory activities in at least one crystal assay. Integrating CaOx inhibitory scores demonstrated that F6, F7 and F8 had the most potent inhibitory activities. NanoLC-ESI-Qq-TOF MS/MS identified 105, 93 and 53 proteins in F6, F7 and F8, respectively. Among them, 60 were found in at least two fractions and/or listed among known inhibitors with solid experimental evidence in the StoneMod database (https://www.stonemod.org). Interestingly, 10 of these 60 potential inhibitors have been reported with lower urinary levels in CaOx stone formers compared with healthy (non-stone) individuals, strengthening their roles as potent CaOx stone inhibitors. Our study provides the largest dataset of potential CaOx stone inhibitory proteins that will be useful for further elucidations of stone-forming mechanisms and ultimately for therapeutic/preventive applications.

Association between tea consumption and risk of kidney stones: results from dose-response meta-analysis of prospective studies and Mendelian randomization analysis

PURPOSE

The association between tea consumption and kidney stones is inconsistent in observational studies. Thus, we performed a dose-response meta-analysis of prospective cohort studies and a two-sample Mendelian randomization (MR) analysis to identify this association.

METHODS

The prospective cohort studies reporting the relationship between tea consumption and kidney stones were searched from PubMed, the Cochrane Library, EMBASE, and Web of Science from inception to December 1, 2023. For MR analysis, the summary-level data for tea consumption and kidney stones were extracted from the UK Biobank available data and the 8th release of the FinnGen consortium, respectively. The inverse-variance weighted (IVW) method was the primary analytical method.

RESULTS

In our dose-response meta-analysis, four prospective cohort studies involving 1,263,008 participants were included, and tea consumption was found to have significant associations with kidney stones (RR: 0.80, 95% CI: 0.73-0.87). We also observed a substantially linear negative relationship between tea consumption and the risk of kidney stones. In MR analysis, the IVW method indicated that tea consumption was inversely associated with kidney stones (OR: 0.71, 95% CI: 0.53-0.94).

CONCLUSION

Our study confirmed a causal relationship between tea consumption and kidney stones, and higher tea consumption may reduce the risk of kidney stones.

Influence of preoperative urine culture and bacterial species on urogenital sepsis after ureteral flexible lithotripsy in patients with upper urinary tract stones

Objective

This retrospective study aims to identify risk factors for urogenic sepsis in patients with upper urinary tract stones following ureteral flexible lithotripsy (FURL). Additionally, we analyze the clinical characteristics of bacterial infections post-surgery.

Methods

A total of 759 patients who underwent FURL at the Urology Department of Zunyi Medical University were included. Univariate and multivariate Logistic regression analyses were conducted to identify independent risk factors for urogenic sepsis post-FURL. The distribution of bacteria based on preoperative urine cultures was also analyzed. Statistical analysis was performed using R4.2.2 software.

Results

Of the 759 patients, positive preoperative urine culture, urine nitrite positivity, urine white blood cell count (WBC) ≥ 200 cells/μL, residual stones, and neutrophil-to-lymphocyte ratio (NLR) were found to be independent risk factors for urogenic sepsis after FURL. Among the 164 patients with positive preoperative urine cultures, 32 developed urogenic sepsis post-surgery, with 68.75% having positive preoperative cultures. The leading pathogens causing postoperative urogenic sepsis were Escherichia coli (E. coli), Enterococcus faecium, Proteus mirabilis, and Klebsiella pneumoniae. The probabilities of progression to urogenic sepsis were as follows: E. coli 19% (n = 12), Enterococcus faecium 43% (n = 3), Proteus mirabilis 33.3% (n = 1), and Klebsiella pneumoniae 33.3% (n = 1). The ages of affected patients were 47.17 ± 13.2, 53.7, 41, and 79 years, respectively. Rates of comorbid diabetes were 36.4, 66.7, 50, 100%, with nitrite positivity rates at 72.7, 33.3, 50, 0%. Ten female patients were infected with E. coli, while patients infected with Klebsiella pneumoniae had an NLR of 7.62.

Conclusion

Positive preoperative urine culture, urine nitrite positivity, urine WBC ≥ 200 cells/μL, residual stones, and NLR are independent risk factors for urogenic sepsis after FURL. Escherichia coli is the predominant pathogen post-FURL, with notable female prevalence and nitrite-positive urine in infections. Enterococcus faecium infections are associated with diabetes.

Current Practices and Challenges in the Management of Complex Renal Stones in Africa: A Scoping Review

This study reviews the challenges and management strategies for complex renal stones in Africa. Historically viewed as infection or struvite stones, recent studies highlight diverse compositions of staghorn stones. These complex stones pose significant risks, including recurrent urinary tract infections and renal impairment. In the past, conservative management of staghorn stones was associated with high morbidity; thus, surgical intervention was necessary for complete eradication. While percutaneous nephrolithotomy (PCNL) remains the standard, it carries notable risks, leading to a shift towards minimally invasive techniques. This study reviews challenges and management practices for complex renal stones and staghorn calculi in African countries, evaluating stone-free rates and associated complications. A scoping review of the literature, following the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines, was performed. A systematic search was conducted in PubMed, African Journal Online (AJOL) and Google Scholar, yielding 1,101 articles, but only 11 articles satisfied the inclusion criteria. The study included 1,513 patients with 1,582 renal units, predominantly male (67.2%) with an average age of 40.7 years. Percutaneous nephrolithotomy (PCNL) was the primary treatment for the majority (71.3%), followed by open surgery (21.9%), laparoscopic surgery (4.1%), and retrograde intrarenal surgery (RIRS) (2.7%). The stone clearance rates for PCNL, open surgery, laparoscopic pyelolithotomy, and RIRS were 82.8%, 83.7%, 100%, and 92.8%, respectively. Stone sizes ranged between 22 and 80 mm, with 66% being staghorn stones. Complication rates were highest for open surgery (30.8%) and lowest for RIRS (4.7%). Despite PCNL being the global standard, African studies still indicate a high reliance on open surgery, likely due to healthcare infrastructure, resource availability and socioeconomic factors. Enhancing access to urological care and addressing healthcare disparities are imperative for improving staghorn stone management in Africa.

Predictors of Recurrent Urolithiasis in Iran: Findings from a Nationwide Study

BACKGROUND

Prevention of urinary stone recurrence is the ultimate goal in urolithiasis patients. In this study, we aimed to investigate the national prevalence rate and possible determinants of increased urolithiasis recurrence risk in a nationwide study in Iran.

METHODS

All data regarding stone occurrence and recurrence episodes were extracted from the cross-sectional Iran National Stone Survey (INSS) study, and the possible determinants of recurrence were evaluated in the subset of 2913 patients who had a positive history of at least one episode of urolithiasis.

RESULTS

The national prevalence rate of recurrent urolithiasis was 2.6% (95% CI: 2.5, 2.8) in Iran. Moreover, the relative ratio of recurrent stone formers to all stone formers was 39.8% (95% CI: 38.0, 41.6). Our univariable truncated negative binomial regressions suggested that a positive history of urolithiasis in the patient's father (prevalence ratio [PR] [95% CI]=1.83 [1.39, 2.41], P<0.001), mother (PR [95% CI]=1.92 [1.39, 2.66], P<0.001) or brother (PR [95% CI]=1.32 [1.03, 1.69], P=0.026); and residence in urban areas (PR [95% CI]=1.27 [1.04, 1.55], P=0.016) were significant predictors of repetitive recurrence episodes. However, when incorporated into a multivariable truncated negative binomial regression model, the only significant predictors of more frequent recurrence episodes were a positive history in father (PR [95% CI]=1.66 [1.24, 2.22], P<0.001) and mother (PR [95% CI]=1.68 [1.20, 2.36], P=0.002); and urban residence (PR [95% CI]=1.24 [1.01, 1.51], P=0.031).

CONCLUSION

Our results indicate that a positive family history of urolithiasis in mother and father and residence in urban areas are the significant predictors of recurrence risk in urolithiasis patients in Iran.

Place of urolithiasis in the spectrum of urological pathologies, practices and use of endourological procedures in the management of calculi of the upper urinary tract: results of a survey of referral centres in Africa

Our aim was to determine the current trend of endourology in the management of upper urinary tract calculi in Africa reference centres. We conducted an online multiple-choice questionnaire survey involving 46 centres from 27 countries using a structured well-designed Google Form (®) questionnaire. The questionnaires were distributed to the head of service through their emails. The questions collected demographic data about the centre, the epidemiology of urolithiasis, diagnostic means and management of upper urolithiasis, especially access to endourology procedures and their practices. Descriptive analyses were performed. The participation rate was 77.9%. Urinary lithiasis was one of the three main pathologies encountered in 42/46 centres. 33 centres had easy access to CT scanners and 34 had operating theatres equipped with endo-urological surgery equipment. Of these 34 centres, 30 perform endourology for the management of upper urinary tract stones. Rigid ureteroscopy is the main technique used by the centres. It is the only endourology technique used for stone management by 12 centres (40%). 7/30 (23.3%) have the option of performing rigid ureteroscopy, flexible ureteroscopy and percutaneous nephrolithotomy. The frequency of procedures varies widely, with 43.3% rarely performing endourological surgery. Seventeen centres have their operating theatre equipped with a fluoroscope and 6/42 centres have extracorporeal lithotripsy. Open surgery is still used in 29/42 centres (69.1%). Laparoscopy is available in 50% of centres, but none reported performing laparoscopic lithotomy. In Africa, urinary lithiasis plays an important role in the activities of referral centres. Modern management techniques are used to varying degrees (not all centres have them) and with very variable frequency. Open surgery is still widely performed as a management. Rigid ureteroscopy is the main endourological technique. It is essential to develop the practice of modern urology in Africa, mainly endourology.

Does displacement of lower pole stones during retrograde intrarenal surgery improves stone-free status? A systematic review and meta-analysis

PURPOSE

Kidney stones are one of the most common urological diseases worldwide. The size and location of the stone are the most important factors in determining the most suitable treatment options. The aim of this review was to evaluate the displacement of lower pole stones.

METHODS

Three studies assessing the efficacy of translocating kidney stones from the lower pole of the kidney to other locations during retrograde intrarenal surgery published in the last 20 years were included. A systematic search was conducted in the PubMed, Embase, Latin American and Caribbean Health Sciences Literature (LILACS), and Web of Science databases using the following search terms: "Lower pole," "Lithotripsy." Meta-analysis was performed using Review Manager version 5.4.

RESULTS

Stone-free rates were improved through displacement (odds ratio - OR = -0.15; 95% confidence interval-95%CI -0.24--0.05; p = 0.002; I2 = 21%), but at the cost of increased surgical duration (mean difference = -12.50; 95%CI -24.06--0.95; p = 0.03; I2 = 94%). Although this represents a potentially negative outcome, the improvement in clearance rates justifies the additional investment of time and effort.

CONCLUSIONS

Displacement of lower pole kidney stones for subsequent lithotripsy brings significant benefits in terms of stone-free rate, with no difference in laser energy usage. However, it results in increased surgical time. Despite these factors, the benefits to patients undergoing the procedure are substantial.

A Giant Kidney Stone in a 50-Year-Old Mayan Gardener From the Yucatan Peninsula: A Case Report

Urolithiasis is a prevalent urological condition characterized by stone formation in the urinary tract, but stones weighing more than 100 g are rare. The Mayan and Mestizo populations in Yucatan have been identified as being at an increased risk of urolithiasis because of the coexistence of environmental, genetic, metabolic, and lifestyle risk factors. The patient's occupation may play a significant role in enhancing these factors. Here, we report the case of a Mayan gardener with a giant kidney stone weighing 1,154 g, one of the largest ever reported from Mexico.

The causal association between smoking, alcohol consumption and risk of upper urinary calculi: insights from a Mendelian randomization study

Background: The causal link between smoking, alcohol consumption, and upper urinary calculi remains uncertain in observational studies due to confounding factors. To uncover potential causal associations, we utilized two-sample univariable and multivariable Mendelian randomization (MR) methods. Methods: Five risk factors related to lifestyles (cigarettes per day, lifetime smoking index, smoking initiation, drinks per week and alcohol intake frequency) were chosen from the Genome-Wide Association Study (GWAS). Upper urinary calculi were obtained from the FinnGen and United Kingdom Biobank consortium. Inverse-variance-weighted (IVW) was mainly used to compute odds ratios (OR) and 95% confidence intervals (Cl). While diligently scrutinizing potential sources of heterogeneity and horizontal pleiotropy via the rigorous utilization of Cochran's Q test, the MR-PRESSO method, and MR-Egger. Results: The summary OR for upper urinary calculi was 0.6 (IVW 95% CI: 0.49-0.74; p = 1.31 × 10-06) per standard deviation decrease in drinks per week. Interestingly, the genetically predicted alcohol intake frequency was associated with a significantly increased risk upper urinary calculi (OR = 1.27; 95% CI: 1.11-1.45; p = 0.0005). Our study found no association between smoking initiation, the number of cigarettes per day, and the lifetime smoking index and the risk of upper urinary calculi. By adjusting for body mass index and education, estimates of drinks per week remained consistent in multivariate MR analyses, while alcohol intake frequency became non-significant. Conclusion: MR analysis showed that drinks per week was negatively associated with upper urinary calculi, whereas the effect of tobacco on upper urinary calculi was not significant and the detrimental effect of alcohol intake frequency on upper urinary calculi became non-significant after adjusting for BMI and education.

Application of tip-bendable ureteral access sheath in flexible ureteroscopic lithotripsy: an initial experience of 224 cases

INTRODUCTION

During the last decades, the advent of flexible ureteroscopic lithotripsy has revolutionized the management of upper urinary tract stones. We designed a patented tip-bendable ureteral access sheath to facilitate stone clearance. Our current study reported our initial experience of 224 cases.

MATERIALS AND METHODS

The study is a descriptive, retrospective analysis. The initial 224 cases, operated consecutively by one surgeon during 16 months, were reviewed. The novel tip-bendable ureteral access sheath was applied in the procedure. Demographics, laboratory tests, and peri- and postoperative findings (operation duration, stone-free rate (SFR), utilization of flexible instruments and complications) were analyzed.

RESUTLS

The median age of the patients was 56 years and the mean stones size was 2.3 ± 1.3 cm. There were 63 cases of upper ureteral stone, 93cases of renal stone and 68 cases of ureteral-renal stones. The mean operative time was 69.2 ± 65.2 min. The immediate stone-free rate was 76.8% and the 1 month post-operative stone-free rate was 97.3%. Most cases(95.5%)were success in single session. Two patient experienced post-operative fever. There was no unplanned readmission. The frequency of post-operative complications was estimated at 0.89% (Clavien I).

CONCLUSION

Flexible ureteroscopic lithotripsy with tip-bendable ureteral access sheath is a safe and effective procedure, which can achieve excellent stone clearance.

Calcium Carbonate Urolithiasis in a Pediatric Patient: A Case Report

Urinary stones composed of calcium carbonate are extremely rare, accounting for 0.01%-1.4% of urolithiasis (UL) cases. Urolithiasis is an infrequent condition in the pediatric population worldwide and in Mexico; nevertheless, the incidence in the Yucatán Peninsula is higher than that reported in other areas of Mexico and the world. Urolithiasis is the second most common urinary disease among pediatrics in the Yucatán Peninsula, which makes it an endemic region for this disease. We describe the case of a five-year-old male from the southeast region of Mexico who presented with signs and symptoms of urinary tract infection (UTI) and was diagnosed with bilateral staghorn stones of calcium carbonate, successfully treated by mini endoscopic combined intra-renal surgery, and dietary adjustments to prevent recurrence.

Efficacy and safety of various endosurgical procedures for management of large renal stone: a systemic review and network meta-analysis of randomised control trials

Urolithiasis is the most common benign urological health condition. It has contributed sizeable burden of morbidity, disability, and medical health expenditure worldwide. There is limited high level of evidence on the efficacy and safety of treatment options of large renal stones. This network meta-analysis has examined the effectiveness and safety of various large renal stone management strategies. Systematic review and network meta-analysis (NMA) study design was employed to summarize comparative randomized controlled trials on humans with a diagnosis of renal stone larger than or equal to 2 cm in size. Our searching strategy was based on the Population, Interventions, Comparison, Outcomes, and Study (PICOS) approach. Medline via PubMed, Embase, Google scholar, SCOPUS, Science Direct, Cochrane library, Web of Science, and ClinicalTrials.gov were searched from inception to March 2023 to find eligible articles. Data extraction, screening, selection and risk of bias assessment were conducted by two independent reviewers. We found ten randomised control trials which consists 2917 patients, nine of them were labeled as low risk and one article was high risk. This network meta-analysis found that SFR was 86% (95% CI 84-88%) for Mini-PCNL, 86% (95% CI 84-88%) for standard PCNL, 79% (95% CI:73-86%) for RIRS, and 67% (95%CI:49-81 for staged URS for management of large renal stone. Overall complication rate was 32% (95% CI 27-38%) for standard PCNL, 16% (95% CI 12-21%) for Mini-PCNL, and 11% (95% CI 7-16%) for RIRS. Mini-PCNL (RR = 1.14 (95% CI 1.01-1.27) and PCNL (RR = 1.13 (95% CI 1.01-1.27)) were statistically associated with a higher SFR compared to RIRS. The pooled mean hospital stays were 1.56 days (95% CI 0.93-2.19) for RIRS, 2.96 days (95% CI 1.78-4.14) for Mini-PCNL, 3.9 days (95% CI 2.9-4.83) for standard PCNL, and 3.66 (95% CI 1.13-6.2) for staged URS. Mini-PCNL and standard PCNL were the most effective treatment options with significant morbidity and length of hospital stay, while RIRS was the safest management option with acceptable SFR, low morbidity, and short hospital stay.

Efficacy and safety of surgical treatment for 1-2 cm sized lower pole of renal stone: network meta-analysis of randomized control trials

The management of medium-sized (1-2 cm) lower poles renal stone has been a contentious topic for endourologists. There are limited evidences to answer the best management options for medium-sized lower pole renal stone. This network meta-analysis provided high-level evidences on efficacy and safety of profile of PCNL, Mini-PCNL, Ultra-PCNL, RIRS, Micro-PCNL, SWL for management of medium-sized lower pole renal stone. Systemic review and network meta-analysis (NMA) of randomized control trials was conducted. The PICOS (Population, Interventions, Comparison, Outcomes, and Study) approach was used to look for relevant studies. Searches were conducted at major electronic databases like Medline via PubMed, Embase, Google Scholar, SCOPUS, ScienceDirect, Cochrane library, Web of Science, and ClinicalTrials.gov to find relevant articles from the inception to April 19, 2023. Fourteen randomized control trials involving 2194 patients were among these studies that met the eligibility criteria. Pooled SFR was Mini-PNCL 98% (95% CI 96-99%), Ultara-PCNL 96% (95% CI 93-98%), RIRS 90% (95% CI 88-92%), PCNL 88% (95% CI 85-92%), Micro-PCNL 77% (61-88%) and SWL 69% (95% CI 65-74%). Mini-PCNL provided a statistically significant higher SFR compared to RIRS (RR = 2.43 91.52; 3.89)), Micro-PCNL (RR = 3.19 (1.09; 9.38)), and SWL (RR = 6.17 (3.65; 10.44)), but there was no statistical significance with standard PCNL (RR = 1.06 (0.52; 2.16)) and Ultra-PCNL (RR = 1.37 (0.75; 2.51)) for management of medium-sized lower pole renal stone. The order of SUCRA values for complication rate was as follows: PCNL(90%), Micro-PCNL(70%), Mini-PCNL(50%), Ultra-PCNL(50%), RIRS(40%), and SWL(10%). The current pooled evidence from fourteen randomized control trials revealed that Mini-PCNL, Ultra-PCNL, and standard PCNL are likely the best treatments for medium-sized lower poles when SFR over a short period of minimal session is a priority. These treatment options have a higher rate of complications, longer hospital stays, and acceptable operations time. RIRS and SWL treatment have acceptable efficacy stone-free rate with low complication rate, short hospital stays, and operation time. These treatment option would be the best fit for solitary kidney, coagulopathy, and comorbidity.