Associations of body mass index and waist circumference with hospitalization risk of kidney stones in Chinese adults / 中华流行病学杂志

Objective: To evaluate the associations of body mass index (BMI) and waist circumference with hospitalization risk of kidney stones in Chinese adults. Methods: This study used long-term follow-up data from China Kadoorie Biobank. After excluding participants with chronic kidney disease, cancer, and extreme BMI or waist circumference values at baseline, 502 096 participants were included in the present analysis. Cox proportional hazards regression models were used to estimate the associations of BMI and waist circumference with hospitalization risk of kidney stones. Results: During an average follow-up period of (10.7±2.2) years, 12 396 participants were hospitalized for the first time with kidney stones. Using the participants with BMI (kg/m2) of 20.5-22.4 as reference, the multivariable-adjusted HR (95%CI) for those with BMI of <18.5, 18.5-20.4, 22.5-23.9, 24.0-25.9, 26.0-27.9, 28.0-29.9, and ≥30.0 were 0.96 (0.87-1.05), 0.94 (0.88-1.00), 1.11 (1.05-1.17), 1.25 (1.18-1.32), 1.29 (1.21-1.37), 1.39 (1.28-1.50), and 1.54 (1.40-1.71), respectively. For every 1 kg/m2 increase in BMI, the HR of kidney stones hospitalization increased by 4% (HR=1.04, 95%CI: 1.04-1.05). Using the participants with waist circumference (cm) of 75.0-79.9 as reference, the multivariable-adjusted HR (95%CI) for those with waist circumference of <65.0, 65.0-69.9, 70.0-74.9, 80.0-84.9, 85.0-89.9, 90.0-94.9, and ≥95.0 were 0.82 (0.74-0.91), 0.85 (0.80-0.92), 0.95 (0.89-1.00), 1.16 (1.09-1.22), 1.22 (1.15-1.30), 1.28 (1.19-1.38), and 1.46 (1.35-1.58), respectively. For every 5 cm increase in waist circumference, the HR of kidney stones hospitalization increased by 9% (HR=1.09, 95%CI: 1.08-1.10). After mutually adjusting for BMI and waist circumference in the above models, the association between BMI and hospitalization risk of kidney stones disappeared. In contrast, the association between waist circumference and hospitalization risk of kidney stones remained unchanged. Conclusions: BMI and waist circumference were positively associated with hospitalization risk of kidney stones. The increased waist circumference was an independent risk factor for kidney stones among Chinese adults.

Influence of socioeconomic disparities, temperature and humidity in kidney stone composition / Influência de disparidades socioeconômicas, temperatura e umidade na composição de cálculos renais

Abstract Introduction: Large variations in demographic, economic and environmental factors might influence the worldwide distribution of urolithiasis, but scarce data are available concerning their associations with stone composition. We aimed to evaluate the frequency and composition of kidney stones and their associations with temperature, humidity, and human development index (HDI). Materials and Methods: A total of 1,158 stones from distinct patients (47±14 years old, male/female 2:1) were included. The mean annual temperature and relative humidity of each town were considered separately. Results: Calcium oxalate monohydrate (COM) was disclosed in 38.8% of patients, calcium oxalate dihydrate (COD) in 22.1%, mixed COD/apatite in 9.4%, pure apatite in 1.9%, brushite in 1.8%, struvite in 8.3%, pure uric acid in 11.1%, mixed uric acid/COM in 5.6%, and cystine/rare types in 0.8%. Mean HDI of all pooled cities was 0.780±0.03. However, people living in HDI<0.800 regions had twice the odds of having a struvite stone versus those living in HDI>0.800 (OR=2.14, 95% CI 1.11-4.11). Furthermore, a progressive increase in the struvite stones frequency from 4.5 to 22.8% was detected from HDI>0.800 through HDI<0.700. No significant difference for other stone types was disclosed. Separate logistic regression models assessed the association of each stone composition with gender, temperature, humidity and HDI as covariates. Conclusion: Patients living in low HDI areas are more prone to develop struvite stones, possibly due to lower access to healthcare. Temperature and humidity did not represent a specific risk factor for any stone type in the present sample.

Resumo Introdução: Grandes variações em fatores demográficos, econômicos e ambientais podem influenciar a distribuição mundial da urolitíase, mas há muito pouco dado disponível sobre suas associações com a composição do cálculo renal. Nosso objetivo foi avaliar a frequência e composição dos cálculos renais e suas associações com temperatura, umidade e índice de desenvolvimento humano (IDH). Materiais e Métodos: Foram incluídos 1.158 cálculos de pacientes distintos (47 ± 14 anos, masculino / feminino 2:1). A temperatura média anual e a umidade relativa de cada cidade foram consideradas separadamente. Resultados: O oxalato de cálcio monohidratado (COM) foi detectado em 38,8% dos pacientes; oxalato de cálcio dihidratado (COD) em 22,1%; mistos de COD/apatita em 9,4%; apatita pura em 1,9%; brushita em 1,8%; estruvita em 8,3%, ácido úrico puro em 11,1%; mistos de ácido úrico /COM em 5,6% e cistina/tipos raros em 0,8%. O IDH médio de todas as cidades em conjunto foi de 0,780 ± 0,03. No entanto, indivíduos que vivem em regiões com IDH <0,800 apresentaram duas vezes a razão de chances de ter cálculo de estruvita do que aqueles que vivem em cidades com IDH > 0,800 (OR = 2,14; IC 95% 1,11-4,11). Além disso, um aumento progressivo na frequência de cálculos de estruvita de 4,5 para 22,8% foi detectado em IDH> 0,800 até IDH <0,700. Não foi observada nenhuma diferença significante para outros tipos de cálculos. Modelos separados de regressão logística foram utilizados para avaliar a associação de cada tipo de cálculo com gênero, temperatura, umidade e IDH como covariáveis. Conclusão: Pacientes que vivem em áreas com baixo IDH são mais propensos a desenvolverem cálculos de estruvita, possivelmente devido ao menor acesso à assistência médica. A temperatura e a umidade não representaram um fator de risco específico para qualquer tipo de cálculo na presente amostra.

Kidney stones: composition, frequency and relation to metabolic diagnosis

Nephrolithiasis is one of the most frequent urologic diseases. The aim of this paper is to study the composition and frequency of 8854 patient kidney stones and in a subset of them their metabolic risk factors to be related to their type of calculi. Physicochemical and crystallographic methods were used to assess kidney stone composition. In a subset of 715 patients, we performed an ambulatory metabolic protocol with diagnostic purposes. From the total sample 79% of stones were made of calcium salts (oxalate and phosphate), followed by uric acid stones in 16.5%, calcium salts and uric acid in 2%, other salts in 1.9% and cystine in 0.6%. Male to female ratio was almost three times higher in calcium salts and other types of stones, reaching a marked male predominance in uric acid stones, M/F 18.8 /1.0. The major risk factors for calcium stones are idiopathic hypercalciuria, followed by unduly acidic urine pH and hyperuricosuria. In uric acid stones unduly acidic urine pH and less commonly hyperuricosuria are the most frequent biochemical diagnosis. Our results show that analysis of kidney stones composition and the corresponding metabolic diagnosis may provide a scientific basis for the best management and prevention of kidney stone formation, as well as it may help us to study the mechanisms of urine stone formation.

La litiasis renal es una de las enfermedades urológicas más frecuentes. El objetivo de este trabajo fue estudiar la composición y frecuencia de 8854 cálculos renales y evaluar en un subgrupo de ellos la relación de los factores de riesgo metabólicos con el tipo de cálculo hallado. Se utilizaron métodos fisicoquímicos y cristalográficos para evaluar la composición de los cálculos renales. En un subgrupo de 715 pacientes, se pudo realizar un protocolo metabólico ambulatorio con fines diagnóstico. De la muestra total, 79.0% de los cálculos fueron de sales de calcio (oxalato y fosfato), seguido por cálculos de ácido úrico en 16.5%, sales de calcio y ácido úrico en 2.0%, otras sales en 1.9% y cistina en 0.6%. La relación hombre/mujer fue casi tres veces mayor en las sales de calcio y otros tipos de cálculos, alcanzando un marcado predominio en varones con cálculos de ácido úrico, M/F 18.8/1.0. Los principales factores de riesgo para los cálculos de calcio fueron la hipercalciuria idiopática, seguida del pH urinario excesivamente ácido y la hiperuricosuria. En los cálculos de ácido úrico el pH urinario excesivamente ácido y con menor frecuencia la hiperuricosuria fueron los diagnósticos más frecuentes. Nuestros resultados muestran que el análisis de la composición de los cálculos renales y el correspondiente diagnóstico metabólico pueden proporcionar una base científica para el mejor manejo y prevención en la formación de cálculos renales, así como que nos puede ayudar a estudiar los mecanismos de formación de los mismos.

A large 15 - year database analysis on the influence of age, gender, race, obesity and income on hospitalization rates due to stone disease

ABSTRACT Purpose: To assess the public hospitalization rate due to stone disease in a large developing nation for a 15-year period and its association with socio-demographic data. Materials and Methods: A retrospective database analysis of hospitalization rates in the Brazilian public health system was performed, searching for records with a diagnosis code of renal/ureteral calculi at admission between 1998­2012. Patients managed in an outpatient basis or private care were excluded. Socio-demographic data was attained and a temporal trend analysis was performed. Results: The number of stone-related hospitalizations increased from 15.7%, although the population-adjusted hospitalization rate remained constant in 0.04%. Male:female proportion among hospitalized patients was stable (49.3%:50.7% in 1998; 49.2%:50.8% in 2012), though there was a significant reduction in the prevalence of male hospitalizations (−3.8%;p=0.041). In 2012, 38% of hospitalized patients due to stone disease had 40­59 years-old. The ≥80 years-old strata showed the most significant decrease (−43.44%;p=0.022), followed by the 20­39 (−23.17%;p<0.001) and 0­19 years-old cohorts (−16.73%;p=0.012). Overall, the lowest relative hospitalization rates were found for yellow and indigenous individuals. The number of overweight/obese individuals increased significantly (+20.6%), accompanied by a +43.6% augment in the per capita income. A significant correlation was found only between income and obesity (R=0.64;p=0.017). Conclusions:The prevalence of stone disease requiring hospitalization in Brazil remains stable, with a balanced proportion between males and females. There is trend for decreased hospitalization rates of male, <40 and ≥80 years-old individuals. Obesity and income have a more pronounced correlation with each other than with stone disease.

Normocalcemic primary hyperparathyroidism in clinical practice: an indolent condition or a silent threat? / Hiperparatireoidismo primário normocalcêmico na prática clínica: condição indolente ou ameaça silenciosa?

OBJECTIVE: To describe the characteristics of normocalcemic primary hyperparathyroidism (NPHPT) in patients seen for osteoporosis evaluation. PATIENTS AND METHODS: We examined the records of 156 women who came to the hospital to be screened for osteoporosis. Measurements of total calcium, PTH, 25-hydroxy vitamin D, and β-C-telopeptide were recorded. Bone mineral density and T-scores were evaluated by densitometry of the lumbar spine, femoral neck and distal one-third of the radius. The latter was only measured in patients with primary hyperparathyroidism. Nephrolithiasis and bone fractures were documented by a review of the medical records. RESULTS: We identified 14 patients with NPHPT, accounting for 8.9 percent of the population studied. In the medical records, the occurrence of kidney stones was reported in 28.6 percent of the patients with NPHPT, in contrast with only 0.7 percent of the noncarriers. Regarding the presence of general fractures, 21.4 percent of the patients with NPHPT were affected versus 16.2 percent of noncarriers. CONCLUSION: Data from our study suggest that NPHPT has a diverse phenotypic presentation, implying that this may not be an "indolent" disease.

OBJETIVO: Avaliar as características do hiperparatireoidismo primário normocalcêmico (HPTPN) em pacientes atendidos para avaliação de osteoporose. PACIENTES E MÉTODOS: Foi realizada análise de um banco de dados de 156 mulheres que procuraram atendimento para avaliação de osteoporose. Todas apresentavam dosagem de cálcio sérico, PTH, 25-hidroxi-vitamina D e C-telopeptídeo. A densidade mineral óssea e escore-T foram avaliados por meio de densitometria óssea de coluna lombar, colo do fêmur e rádio distal, este último apenas em pacientes com hiperparatireoidismo renal primário. Nefrolitíase e fraturas ósseas foram documentadas pela revisão dos prontuários. RESULTADOS: Foram identificadas 14 pacientes com HPTPN, correspondendo a 8,9 por cento da população estudada. Nos registros médicos, o relato da existência de litíase renal ocorreu em 28,6 por cento dos portadores de HPTN em contraste com apenas 0,7 por cento nas mulheres não portadoras, com um p < 0,001. CONCLUSÃO: Os dados do estudo sugerem que HPTPN tem uma apresentação fenotípica variada, podendo não ser uma patologia "indolente".

Microlithiasis and Nephrolithiasis among infants: Is it a new phenomenon?

Although nephrolithiasis is a rare but a serious problem for children's health, recent data has showed that the prevalence of pediatric nephrolithiasis has increased in both developed and developing countries. North and West of Iran, as a country located in Afro-Asian stone-forming belt, has the highest incidence for renal stones among adults. This study aimed to determine the incidence of microlithiasis and nephrolithiasis among infants in a city at North West of Iran. It was a cross-sectional study on infants aged less than one year old, diagnosed as patients with microlithiasis and nephrolithiasis, over three months period [since March 2010] who were referred to pediatrician in a city of East Azerbaijan province. Demographic data [age, sex], number of stones, size of stones, presence of hydronephrosis in kidneys, history of jaundice and family history of stone disease were recorded. Incidence of microlithiasis and nephrolithiasis was 0.04866 and 0.03244, respectively. Fever [30%] was the main cause of complication. Male to female ratio was 4:1, and 20% of our subjects had a positive history of nephrolithiasis in their first degree relatives. This area has the highest incidence of microlithiasis and nephrolithiasis. Emergent population-based and case-control studies are needed to report its incidence/prevalence of nephrolithiasis in other parts of the country as well as to find its etiology

Serum and urinary calcium in stone formers and non-stone formers

Geographical variation in the rates of kidney stones has been observed for many years. Pakistan is situated in stone belt. Calculus diseases is endemic in Pakistan, perhaps the incidence in Pakistan is highest in the world. To evaluate etiology and biochemical risk factors [inorganic phosphate] in the Peshawar. Study was conducted at LHR and Hayatabad Hospitals of Peshawar for the period of nine months. Two hundred patients and same number of controls were selected. The mean value of mean inorganic phosphate in non stone formers were less than that of stone formers. The mean of urinary inorganic phosphate excretion in stone formers was greater than that of non-stone formers. We conclude that inorganic phosphate is an independent risk factor for renal stone formation

Gender and urinary pH affect melamine-associated kidney stone formation risk

Melamine was known as a new risk for kidney stone due to recent incidences of milk powder contamination in China. Here, we performed a retrospective study to investigate whether age, gender, and urinary pH affect melamine-associated kidney stone risk. A retrospective review was performed of 217 children aged less than 3 years old. All children had a history of being fed with Sanlu milk powder contaminated by melamine, and underwent a clinical screening on kidney stone in Shenyang from November 2008 to February 2009. A comparison with the Chi-square was conducted between 83 cases and 125 normal subjects. The difference between children's gender, age, and urinary pH was evaluated. A total of 208 subjects, 136 boys and 72 girls, were included in the study. Significant association was observed between melamine-associated kidney stone risk and gender [odds ratio [OR], 2.03; 95% confidence interval [CI], 1.11-3.74; P=0.02] and urinary pH [OR, 1.78; 95% CI, 1.01-3.11; P=0.04], respectively. Male children were at about twofold increased melamine-associated kidney stone risk compared with female children. Acidic urine showed about 1.78-fold increased melamine-associated kidney stone risk compared with normal urine. Our investigation results showed an association of gender and urinary pH with melamine-associated kidney stone formation risk

[Association between dietary factors and renal stones in adults]

Urolithiasis is the third urinary disease and evidence shows that its incidence has increased continually during the past decades. The relationship between urinary stones and diet is known to some extent, but there are controversies about it. The aim of this study was to determine the relationship between dietary habits, food intake patterns and urinary stone disease. This was a case-control study with 161 adult patients with urinary stone disease referred to Hasheminejad Urology Center, Tehran, Iran, and 254 healthy subjects matched for age and gender. All the subjects were interviewed using a questionnaire to obtain data on demographic characteristics, dietary habits, and food consumption frequency. Data were analyzed using SPSS version 14. The independent T-test, chi square and regression were used to examine the differences. Findings showed that male-to-female ratio was 1.98:1. The prevalence of renal stone was highest in men aged between 30 and 50 years and in women aged between 40 and 60 years. There were no differences in height and weight between the two groups, but BMI was significantly higher in the case group [p=0.007]. A family history of renal stones was observed more frequently in the patients [59% compared to 31.9%; p<0.001]. The mean intakes of food sources of several nutrients were lower in the patients than in the healthy subjects: calcium [p=0.048], phosphorus [p=0.001], potassium [p<0.0001], vitamin A [p<0.0001], vitamin D [p<0.0001], and vitamin C [p=0.004]. Regression analysis confirmed the differences between the two groups as regards sources of vitamins A and D. The intakes of sources of magnesium and vitamin B6, as well as of foods rich in oxalate, were not significantly different between the 2 groups. Results suggest that there are associations between urinary stone formation and the dietary intakes of nutrients such as calcium, phosphorus, potassium, vitamin A, vitamin D, and vitamin C. Considering the challenges of treatment and the costs of this relatively common disease, dietary recommendations may be an easy and cost-effective way to reduce its burden

[Incidence of kidney stones in hypertensive patients]

As the population grows older and more obese, hypertension eventually develops in more people during their life span. The prevalence of kidney stone disease is estimated at 1% to 15%, varying in degree according to age, gender, race and geographic location. The objective of this study was to determine the frequency of nephrolithiasis in hypertensive patients. Using simple non probability sampling, a total of 200 patients were referred to Aria and Bahman 22[nd] Hospitals entered this study. The exclusion criteria were determined as: those subjects that had used carbonic anhydrase or thiazide; those who had a history of surgery on their urinary system; those who had been diagnosed with HTN before affected by nephrolithiasis. The main group was divided into 2 groups: Group 1 who had normal blood pressure [control group] and group 2, hypertensive patients [case group]. All the patients were examined using both ultrasound and supine abdominal X ray [KUB] for stone scanning. Then, statistical analyses were conducted using t-test, chi-square test and Fisher's Exact Test. All the subjects signed a testimonial before the rest. The comparison of sex and age distribution between the case and the control groups showed no significant differences. Also, the results of Ultra sonograms showed echogenic density of the urinary system prevailing in 4.2% of the patients in the control group and in 25% of those in the hypertensive [case] group [P<0.05]. Moreover, KUB revealed significantly lower frequency of stone density in kidneys in the control group [4.2%], as compared to the hypertensive group [21%]. As a whole, nephrolithiasis was observed in 4% of the patients in the control group and 21% in those subjects in the hypertensive group. Such a difference between the two groups was statistically significant [P<0.001]. we believe that urinary stone is significantly more frequent in hypertensive subjects than normal subjects

Is urinary tract infection a predisposing factor for renal stone formation?

The study was carried out to assess whether Urinary Tract Infection (UTI) is a predisposing factor for Renal Stones (RS) formation. A total of 836 subjects (males 300; females 536) attending Surgery Out Patient Department (OPD) of which were either diagnosed of UTI or had been detected of RS for a period of two years from January 2001 to December 2002 were included. Of the 836, 240 had UTI and 596 were free from UTI. The prevalence of RS was higher without UTI (44.4%) than those with UTI (27.8%) in males. In case of females the result showed (17.6%) and (5.1%) in cases with and without UTI. Chi square test revealed statistically significant difference in the proportion of prevalence between subjects with and without UTI with (p < 0.01) in males and (p < 0.001) in females. Males had higher incidence of RS than females with a prevalence of (p < 0.0001). The higher occurrence of RS was observed in age group between 21-40 years for both genders.

Dados epidemiológicos da litíase renal, em hospital de referência, em Belo Horizonte, Minas Gerais / Epidemiology of renal calculi in a reference hospital in Belo Horizonte, Minas Gerais State

Introduçäo: A litíase renal é uma afecçäo muito comum na prática clínica e múltiplos fatores estäo relacionados com sua etiopatogenia, embora näo tenhamos encontrado estudo algum sobre a epidemiologia da litíase no Brasil. Objetivo: Avaliar a influência da idade, do sexo, da cor da pele e da lateralidade como fatores de risco para cálculo renal. Pacientes e Métodos: Foram estudados 400 prontuários de pacientes com diagnóstico de litíase urinária, nos Serviços de Nefrologia e Urologia do Hospital das Clínicas da Universidade Federal de Minas Gerais, em Belo Horizonte. Todos os diagnósticos foram confirmados pela história clínica associada a métodos de imagem. Resultados: Houve predomínio de pacientes do sexo feminino (54,5 por cento) sobre o masculino com litíase renal. Os doentes brancos constituíram a maioria (75 por cento), seguidos pelos mulatos (23,3 por cento) e, em uma muito pequena proporçäo, pelos negros (1,8 por cento). A idade média foi de 39,81, +- 15,61 anos. Näo houve diferenças quanto à lateralidade dos cálculos, mas os homens tiveram mais cálculos bilaterais do que as mulheres. Conclusäo: Na populaçäo estudada no presente trabalho, o cálculo renal foi mais freqüente em adultos jovens, brancos e do sexo feminino, sem diferenças quanto à lateralidade. Os resultados sugerem uma possível relaçäo entre nefrolitíase e cor da pele.

Hipertrigliceridemia y nefrolitiasis en pacientes con sida que reciben antirretrovirales / Hypertriglyceridemia and nephrolithiasis in HIV patientsreceiving aantiretroviral medication combinations

El objetivo del estudio fue evaluar la prevalencia de hipertrigliceridemia y nefrolitiasis en pacientes con inmunodeficiencia adquirida y tratamiento antirretroviral. Se realizó un ensayo clínico abierto durante 52 semanas, en el Departamento de Medicina Interna del Centro Médico Nacional Adolfo Ruiz Cortines, Instituto Mexicano del Seguro Social, Veracruz. Se integraron dos grupos de manera aleatoria: ambos recibieron zidovudina 500 mg diarios más lamivudina 300 mg/día, pero al grupo I (n = 30) se le adicionó indinavir 2400 mg/día y al grupo II (n = 38) saquinavir 1800 mg/día. Se registraron efectos adversos, ingresos a hospitalización e infecciones oportunistas. Se evaluaron linfocitos CD4, glucosa, triglicéridos, creatinina, hemoglobina, enzimas hepáticas, amilasa y ul-trasonograma renal al ingreso y cada cuatro meses. En todos los pacientes se incremen-taron los niveles de triglicéridos: grupo I, de 131.72 ñ 32.9 a 180.58 ñ 90.14, p < 0.01; grupo II de 131.05 ñ 33.68 a 165.31 ñ 72.12, p < 0.05. La nefrolitiasis se presentó en cuatro pacientes (13.3 por ciento) que recibieron indinavir. En el grupo I (indinavir) se presentó menor número de infecciones intercurrentes, los linfocitos CD4 se incrementaron, de 212.6 ñ 132.7 pasaron a 332.82 ñ 147.38, p < 0.01. En conclusión, ambos esquemas condicionaron hipertrigliceri-demia siendo mayor en el grupo de indinavir aunando a un incremento en la prevalencia de nefrolitiasis.

Chemical composition of upper renal tract calculi in multan

OBJECTIVE: To study the chemical composition of upper renal tract [renal and ureteric] calculi in Multan. SETTING: Department of Urology, Nishtar Hospital, Multan. STUDY PERIOD: September 1992 to February 1999. MATERIAL AND METHODS: A total of 700 renal and ureteric calculi were analyzed by chemical method of Hodgkinson. The commonest were uric acid [28.1%] calculi, followed in frequency by calcium oxalate calculi [26.1%], mixed calculi containing calcium oxalate and uric acid [21.8%] and calculi containing calcium oxalate and calcium phosphate [10.4%]. Other variety of calculi were less common. Uric acid, calcium oxalate and mixed uric acid and calcium oxalate calculi are the main types in Multan region [JPMA 50:145, 2000]

Staghorns, Large, Solitary and multiple renal Calculi in native Saudi patients: a clinical study

To report on the results of a clinical study conducted on a group of native Saudi patients who presented with renal stones of large burden. Ninety four native Saudi patients presented with either multiple, large solitary or staghorn renal stones. We herein describe the clinical details of the following items: age at presentation, sex differences, incidence of recurrent stone disease, pH of urine, associated urinary tract infection, site of occurrence, size of stones, associated hydonephrosis, associated renal congenital anomalies, serum calcium and uric acid levels and finally composition of stones analysed. Bilateral stones occurred in 3 patients making up 97 renal units with stones. The average age at presentation is 40 years. Male to female ratio is 3:1. Previous episode of stone disease occurred in 42% of the patients. Average urinary pH of these patients is 5.40. Urinary tract infection was documented in 13% of the patients and in those with staghorn calculi urease producing organisms were isolated in 31% only. Stones formed on the left side in 49 renal units and on the right side in 48 renal units. Fifty four solitary stones were equal to or exceeding 20mm in maximum diameter in size, seventeen renal units had multiple stones and twenty six had partial and complete staghorn stones. The majority of stone harbouring kidneys [N=83 i.e 86%] were hydronephrotic and congenital anomalies were found in 6 [6%] of them. Hyperuricemia was found in 13 [14%] and high serum calcium level in 2 [2%] patients. Thirty eight stones were analysed. The majority were calcium oxalate in 17 [45%], mixed calcium oxalate and urate in 12 [32%], mixed calcium oxalate and phosphate in 4 [11%], magnesium ammonium phosphate in 3 [8%] and 1 [NUMBER SIGN%] each of pure uric acid and cystine stones. Detailed clinical information on a group of native Saudi patients who presented with large renal stone burden is now at hand. This information can be utilized to design plans for patients' management, selection for appropriate treatment options and encourage future clinical and research study projects

Some aspects of citrate metabolism in renal-stone patients from northeastern Thailand.

In our previous nephrolithiasis studies in the northeast region of Thailand, hypokaliurea and hypocitraturia were the 2 most commonly encountered metabolic abnormalities. This led us to believe that people prone to forming renal-stones in this area were in a state of potassium depletion, a condition which probably caused the low urinary excretion of citrate. Further studies on some aspects of citrate metabolism in these subjects were carried out. Two groups of adult male subjects were included in the study protocol. Group 1 consisted of 20 urban dwellers who were used as normal controls, and group 2 was comprised of 36 renal-stone patients residing in rural villages outside the municipal area. Fasting clotted venous blood and one 24-hour urine specimens were collected and analyzed for creatinine, citrate, calcium, phosphate, magnesium, sodium, potassium, chloride, bicarbonate and uric acid. Values for: creatinine and citrate clearances, the filtered load of citrate and the tubular reabsorption of citrate were then calculated. The results showed that, for both groups, the concentrations of most of the above parameters were within the normal ranges both serum and urine. An exception to this was that the levels of serum potassium and of urinary excretions of sodium, potassium and citrate in people in group 2 were significantly less than those in group 1 (p < 0.005, p < 0.001, p < 0.001 and p < 0.0001, respectively). With respect to citrate metabolism, while the serum citrate levels and the filtered load of citrate were not different between the 2 groups, the average percentage of renal tubular reabsorption of group 2 (95 +/- 1.1%) increased significantly (P < 0.0001)in comparison to group 1 (85 +/- 1.6%). Moreover when results from both groups were combined, a significant negative correlation between the renal tubular reabsorption of citrate and the urinary excretion of potassium was clearly seen (r = 0.4001, p < 0.007). Our data suggests that potassium depletion may affect the renal tubular cells in some manner which, consequently, causes an increase in renal tubular reabsorption of citrate. The final outcome of these changes in these renal stone subjects was hypocitraturia.

Estudo da taxa de recorrência em pacientes com litíase renal / Recurrent rate study in patients with renal lithiasis

A taxa de recorrência (TR), em 107 pacientes com litíase renal, mostrou média de 1,43 cálculos/paciente. ano, em tempo médio de 7,3 anos. Em pacientes com menos de quatro anos de doença, a TR foi mais elevada do que no grupo com período mais longo. Observou-se queda progressiva na TR, que se estabiliza aos oito anos de doença até um período acima de 15 anos de doença. Os autores discutem que a TR é elevada em pacientes com menos de quatro anos de doença porque exclui o período de remissao natural. Pacientes operados com > 4 anos de doença e evidência atual de cálculo tiveram TR mais elevada, sugerindo a necessidade de profilaxia.