The relationship between ethnicity and stone composition in a large multi-ethnic London NHS Trust

Purpose Few studies have examined kidney stone composition of an ethnically diverse group living in the same location, we aimed to study this in an ethnically diverse NHS trust. Methods We reviewed all patients (n=312) with laboratory stone analysis and compared their ethnicity with their stone composition. Results Using a Chi Squared analysis there was no significant difference between stone composition in different ethnic groups (p=0.07). Uric acid stones were more common in the White-other group at 22.0% compared to 10.3% for White British, 5.2% for Asian and 9.52% for Black patients. Calcium oxalate stone were more common in the Asian population with 71.9% and Black population at 76.1%, compared with 56.7% in the White British population and 52.6% in the White-other population. Calcium phosphate stones were found commonly in the White British population (26.8%) compared to 18.6% for White-other, 16.7% for Asian and 9.5% for Black patients. Cystine and Struvite stones were found at low levels of between 0-3.4% in each group. Repeat stone formers with calcium oxalate, uric acid or cystine stones formed the same stone again 100.0% of the time. The odds for the Black population having a stone analysed (OR 0.62, CI 0.39-0.97, p=0.04) was significantly lower than the local population, and for the Asian population this was significantly higher (OR 1.31, CI1.05-1.62, p=0.01), Conclusion Uric acid stones are found more frequently in the White-other population and calcium oxalate stones are found more frequently in the Asian and black population. However, these results were not statistically significant. The odds ratio of having a stone was significantly higher in the Asian population and lower in the Black population.

Prediction of Uric Acid Component in Nephrolithiasis Using Simple Clinical Information: A Machine Learning-Based model

There is a great need for a diagnostic tool using simple clinical information collected from patients to diagnose uric acid (UA) stones in nephrolithiasis. We built a predictive model making use of machine learning (ML) methodologies entering simple parameters easily obtained at the initial clinical visit. Socio-demographic, health, and clinical data from two cohorts (A and B), both diagnosed with nephrolithiasis, one between 2012 and 2016 and the other between June and December 2020, were collected before nephrolithiasis treatment. A ML-based model for predicting UA stones in nephrolithiasis was developed using eight simple parameters - sex, age, gout, diabetes mellitus, body mass index, estimated glomerular filtration rate, bacteriuria, and urine pH. Data from Cohort A were used for model training and validation (ratio 3:2), while data from Cohort B were used only for validation. One hundred forty-six (13.3%) of 1098 patients Cohort A and three (4.23%) of 71 patients in Cohort B had pure UA stones. For Cohort A, our model achieved validation AUC (area under ROC curve) of 0.842, with 0.8475 sensitivity and 0.748 specificity. For Cohort B, our model achieved 0.936 AUC, with 1.0 sensitivity, and 0.912 specificity. This ML-based model provides a convenient and reliable method for diagnosing urolithiasis. Using only eight readily available clinical parameters, it distinguished pure uric acid stones from other stones before treatment.

Dual Energy Computed Tomography (DECT) for Determination of Renal Calculi Composition - In-Vivo Analysis and In-Vitro Comparison with Qualitative Chemical Analysis - A Prospective Comparative Study at a Single Centre at SDM Medical College and Hospital – Dharwad, Karnataka

BACKGROUND Dual energy computed tomography (DECT) is a new method of computed tomography (CT) imaging which allows to determine stone composition in addition to assessing stone morphology. The purpose of this study was to evaluate the role of dual energy CT (DECT) preoperatively to assess the composition of urinary stones and to compare it with post-operative in vitro qualitative chemical analysis as reference standard. METHODS Forty patients (18 male and 22 female) who presented with symptoms of renal stones in the department of urology were included in the study. All 40 patients who were diagnosed to have renal stones clinically and by ultrasonography (USG) kidney, ureter and bladder (KUB) region were subjected to dual energy CT. The stone composition assessed in vivo using DECT preoperatively and in vitro by chemical analysis post operatively after stone extraction by surgical procedure. The results were compared by statistical analysis. Sensitivity, specificity and positive predictive value (PPV) were calculated and descriptive study done using Statistical Package for Social Sciences (SPSS) 20.00 version. Data was analysed by comparing it with correlative qualitative chemical analysis. RESULTS In our study, in vivo analysis using DECT showed most common type of stone was calcium oxalate seen in 20 cases compromising 50 % of total cases. Next common stone type was uric acid stone (22.5 %) followed by cysteine (17.5 %) and calcium hydroxyapatite (10 %) respectively. When the same stones were subjected to ex vivo chemical analysis, one of the calcium oxalate stone came out to be calcium phosphate and one of the cysteine stone came out to be mixed stone. Thus, out of 40 stones, 38 stones were found to have the same result in ex vivo chemical analysis as that of in vivo analysis by dual energy CT. Hence, accuracy of dual energy CT in diagnosis of renal stones was found to be 100 % with CI 91.19 % - 100 %. CONCLUSIONS With dual energy CT, it is possible to determine the composition of renal calculi in vivo non-invasively (with specificity of 100 % in our present study). Therefore, this helps in deciding the modality of treatment pre-operatively whether the stone is amenable to medical management (e.g., Uric acid stones) or requires extracorporeal shock wave lithotripsy (ESWL) or surgical intervention can be determined preoperatively. This helps to reduce the unnecessary financial burden and is found to be time saving. KEYWORDS Renal Calculus, Dual Energy CT, Stone Composition, Uric Acid Stones, Non-Uric Acid Stones, Attenuation, Hounsfield Units HU, Chemical Analysis of Stones.

Metabolic Risk Factors in Patients with Kidney Stones with and without Type 2 Diabetes

Background: In the past few decades, the prevalence of kidney stones in Western countries has increased in parallel with the growing overweight/obesity and type 2 diabetes mellitus rates. An increased insulin resistance in these patients explains, in part, the rising prevalence of uric acid stones. The objective of this retrospective study is to evaluate the metabolic abnormalities in type 2 diabetic and non-diabetic patients with kidney stones. All patients were evaluated following an ambulatory protocol for kidney stones. Methods: A total of 104 diabetic patients (age: 57.8 ± 11 years) and 130 non-diabetic (age: 52.1 ± 6.7 years) patients with kidney stones were selected. Higher rates of body mass index, hypertension, urinary tract infection, gout and hyperuricemia were observed in diabetic patients as compared to the non-diabetics, while similar rates were found for their family history of kidney stones. Results: Urinary pH was lower in diabetic patients than in non-diabetic patients. Metabolic abnormalities were detected in 95.2% and 81.5% of diabetic and non-diabetic, respectively. Unduly acidic urine pH was the most frequent abnormality in diabetic patients while hyperuricosuria was the second more common abnormality. On the other hand, in non-diabetics patients idiopathic hypercalciuria was the most common metabolic abnormality followed by hyperuricosuria. Conclusions: The main risk factor for lithogenesis in type 2 diabetes is unduly acidic urine pH, followed by hyperuricosuria and idiopathic hypercalciuria.

Dual-Energy Multidetector Computed Tomography: A Highly Accurate Non-Invasive Tool for in Vivo Determination of Chemical Composition of Renal Calculi

Introduction. Computed tomography is more accurate than excretory urography in evaluation of renal stones due to its high sensitivity and temporal resolution; it permits sub-millimetric evaluation of the size and site of calculi but cannot evaluate their chemical composition. Dual-energy computed tomography allows evaluating the chemical composition of urinary calculi using simultaneous image acquisition at two different energy levels. The objective of the research was to determine renal stone composition using dual-energy multidetector computed tomography, and its correlation with post-extraction chemical analysis of stones. Materials and Methods. This prospective study was conducted in the Department of Radiodiagnosis and Imaging from September 2017 to March 2019. A total of 50 patients with urolithiasis at the age of 18-70 years were included in the study. Dual-energy computed tomography ratios of various stones were noted, and preoperative composition of calculi was given based on their colour and dual-energy computed tomography ratio. These results were compared with the post-extraction chemical analysis of stones (using Fourier infrared transform spectroscopy as the standard comparative method.) Results. The most common type of calculi in our study population was calcium oxalate stones (78%) followed by uric acid stones (12%), cystine stones (6%) and hydroxyapatite stones (4%). The dual-energy ratio of calcium oxalate, uric acid, cystine and hydroxyapatite stones ranged from 1.38-1.59, 0.94-1.08, and 1.20-1.28 and 1.52-1.57, respectively, with the mean dual-energy ratio of 1.43, 1.01, 1.25 and 1.55, respectively. Dual-energy computed tomography was found to be 100% sensitive and specific for differentiating uric acid stones from non‑uric acid stones. The sensitivity and specificity in differentiating calcium oxalate calculus from non‑calcium oxalate calculus was 97.5% and 90.9%, respectively, with 96% accuracy and kappa value of 0.883 suggesting strong agreement. Conclusions. Dual-energy computed tomography is highly sensitive and accurate in distinguishing between various types of renal calculi. It has vital role in management as uric acid calculi are amenable to drug treatment, while most of non-uric acid calculi require surgical intervention.

Studi Literatur: Obesitas sebagai Faktor Resiko terhadap Kejadian Urolitiasis secara Klinis

The incidence of urolithiasis tends to relapse, causing increased mortality and medical costs. In 2015, there were 22.1 million cases of urolithiasis which caused death in about 16,000 people. Obesity is a risk factor that can increase the incidence of urolithiasis. However, there are differences in the results of studies regarding the relationship between obesity and urolithiasis. This literature review aims to analyze the factors that influence the relationship between obesity and urolithiasis. This literature review study uses a systematic review design. The data source used in this literature review is secondary data in scientific journals that have met the inclusion and exclusion criteria. Based on data synthesis from the fifteen journals studied, twelve journals stated a relationship between obesity and the incidence of urolithiasis. In contrast, the other three stated that there was no relationship between obesity and the incidence of urolithiasis. Obesity is associated with a spectrum of metabolic disorders that lead to increased excretion of urinary lithogenic factors. In addition, obesity can increase urolithiasis in types of calcium oxalate and uric acid stones.

Preliminary Phytochemical screening of Persicaria sagittata: Future prospective for kidney stone

Medicinal plants have bioactive compounds, which are used to treatments of various diseases. In the present study, Persicaria sagittata medicinal plant was used for the preliminary phytochemical screening. Methanol and petroleum ether were used as a solvent for obtaining the extraction of the plant. Both the extracts were further study for qualitative phytochemical screening using standard methods. Phytochemical screening shows that methanolic extract possesses the presence of tannins, flavonoids, and vitamin A as tannins and flavonoids are helpful for the uric acid stones. The study reveals that medicinal plant provides a basis of its use in medicine, improve to further drugs in the pharmaceutical area, and contains different biologically active constituents, and the secondary product is valuable of further analysis.

Composition of Uroliths seen in patients in Abuja, Nigeria: a single centre retrospective analysis of 155 stones

Background Uroliths are stones formed in the urinary tract. Analysis of stones helps to identify risk factors for their development and prevention of recurrence. Standard stone analysis using modern technology is not routinely done in Nigeria. This study sought to determine the chemical composition of urinary stones seen in Abuja, Nigeria. Methods This was a retrospective study on composition of uroliths. Urinary stones surgically removed from 155 patients through minimal access surgical procedures between January 2015 and August 2019 were analysed. Optical crystallography and infrared spectroscopy were used to determine the chemical composition of the urinary stones. Results A total of 155 urinary stones were assembled from the patients. More stones were removed from male patients and the male to female ratio was 1.9:1. Stones were rare in the extremes of age. The predominant location (89.7%) of stones was in the upper urinary tract. All stones were of mixed composition with calcium oxalate accounting for 93.55%. Calcium oxalate, calcium phosphate and uric acid stones were more common in the upper tract, while 2 of the 3 struvite stones were found in the lower tract. Conclusion Stones found in this study were of mixed composition with the most common constituent being Calcium oxalate and the least common, struvite.