Racial variation in gender frequency of calcium urolithiasis

Correlates of nephrolithiasis in US black women: data from the black women's health study

Nephrolithiasis is a common urologic condition and a significant source of patient morbidity and healthcare expenditure. There are few epidemiologic studies of kidney stones focusing exclusively on Black women. We retrospectively assessed the prevalence and correlates of self-reported kidney stones within the Black Women's Health Study (BWHS). Descriptive statistics and multivariable logistic regression models were used to explore factors associated with nephrolithiasis. As of the 2005 follow-up questionnaire, a cumulative total of 1063 women among 43,178 reported ever being diagnosed with kidney stones for a prevalence of 2.64%. Women with a history of nephrolithiasis were older, slightly heavier, and were more likely to have a comorbid condition (e.g., type-2 diabetes, gallstones), drink alcohol, and consume a Western-style diet. A history of gallstone disease was associated with an odds ratio (OR) of 3.59 (95% confidence interval (CI) 3.09-4.17). The OR for consuming ≥ 7 alcoholic beverages/week, compared to none was 0.61 (0.39-0.94), while the OR for high adherence to the Western diet, compared to low adherence was 1.53 (1.23-1.90). Our findings are consistent with previous studies of primarily white populations relating lifestyle-associated risk factors with nephrolithiasis. Despite their lower prevalence of kidney stones, it is important to focus on vulnerable populations such as Black women given their disproportionate burden of metabolic conditions (e.g., obesity, diabetes) related to kidney stone disease.

Influence of climate on the number of hospitalizations for nephrolithiasis in urban regions in Brazil

Introduction:

Nephrolithiasis has a worldwide prevalence of approximately 5 to 15%, and its occurrence is associated with age, sex, race, dietary habits, geographic location, climatic conditions, and other factors. The objective of the present study was to determine the association between climate and the number of hospitalizations for nephrolithiasis (NH) in Brazilian cities located in different climatic regions.

Methods:

We analyzed data from cities with tropical and subtropical climates. The effects of the lowest (LT), mean (MT), and highest (HT) monthly temperatures and relative humidity of the air (RH) were assessed.

Results:

A positive association was found between the number of hospitalizations for nephrolithiasis and temperature ((LT x NH; R²=0.218; P<0.0001) (MT x NH; R²=0.284; P<0.0001) (HT x NH; R²=0.317; P<0.0001)), and a negative association was found between the number of hospitalizations for nephrolithiasis and the relative humidity (RH x NH; R²=0.234; P<0.0001). Interactions were also observed between MT and RH with respect to their effects on the NH, as described by a linear model (NH = 4.688 + 0.296 x MT - 0.088 x RH). The NH was higher in cities with tropical climates than in cities with subtropical climates (82.4 ± 10.0 vs 28.2 ± 1.6; P<0.00001).

Conclusion:

There is an association between the NH and variations in temperature and relative humidity.

Race- and Sex-related Differences in Nephrolithiasis Risk Among Blacks and Whites in the Southern Community Cohort Study

OBJECTIVE

To investigate race-sex associations with risk among whites and blacks in the southeastern United States. The relationship between race, sex, and kidney stone risk is poorly understood.

METHODS

Participants were 42,136 black and white adults enrolled in the Southern Community Cohort Study between 2002 and 2009, with no history of kidney stones and receiving Medicare or Medicaid services. Incident kidney stone diagnoses through December 2014 were determined via linkage with Centers for Medicare and Medicaid Services research files. Hazard ratios (HRs) for associations with race and sex were computed from multivariable Cox proportional hazards models adjusting for baseline characteristics, comorbid diseases, and dietary intakes.

RESULTS

During 116,931 and 270,917 person-years of follow-up for whites and blacks, respectively, age-adjusted incidence rates (95% confidence interval [CI]) were 5.98 (4.73-7.23) and 4.50 (3.86-5.14) per 1000 person-years for white men and women, respectively, while corresponding rates among blacks were 2.19 (1.71-2.67) and 2.47 (2.19-2.75) per 1000 person-years. Risk was higher among whites compared to blacks (HR = 2.23, 95% CI 1.97-2.53). Male sex was significantly associated with risk among whites (HR = 1.45, 95% CI 1.20-1.75), but not among blacks (HR = 0.90, 95% CI 0.75-1.07). Formal tests of interaction by race and sex were statistically significant for all models (P = .01 for fully adjusted model).

CONCLUSION

The association of incident kidney stones with sex differs between whites and blacks. White men have the highest risk, while no difference in risk is observed between black men and women.

Prevalencia de la composición química de Uro Litiasis en pacientes de clínicas privadas

Introducción: La litiasis urinaria, también denominada urolitiasis, es una enfermedad causada por la presencia de cálculos o litos en el interior de los riñones o de las vías urinarias (uréteres, vejiga). Los cálculos renales se componen de sustancias normales de la orina, pero por diferentes razones se han concentrado y solidificado en fragmentos de mayor o menor tamaño. Es una condición frecuente que afecta a más del 10% de la población, en la edad media de la vida y es más frecuente en los hombres. Predomina en personas con hábitos sedentarios o en personas con gran exposición al calor y deshidratación. El análisis por disolución de los cálculos renales nos permite evaluar la composición química del mismo y así tomar las medidas clínicas adecuadas para prevenir su formación y recurrencia. Objetivo: Describir cual es la composición química más frecuente de los litos urinarios en una clínica privada de la ciudad de Guatemala. Describir la frecuencia de presentación entre géneros y su prevalencia en los grupos de edad. Metodología: Diseño descriptivo, transversal. Se realizó el análisis por disolución del cálculo a 80 pacientes de una clínica privada. Se tomaron datos de género y edad de los pacientes. Resultados: De los 80 pacientes analizados se encontraron 75 litos urinarios compuestos por oxalato de calcio (93.75%), 4 de ácido úrico (5%) ,1 de cistina (1.25%) y 0 litos de estruvita (0%). En el estudio participaron 62 pacientes se sexo Masculino (77.5%) y 18 femeninas (22.5%), con un rango de edades de 18 a 80 años y una edad promedio de 41.4 años. Conclusión: La gran mayoría de los litos analizados en el estudio estaban compuestos de Oxalato de Calcio, lo cual concuerda con las estadísticas de la NHANES donde se afirma que aproximadamente el 80% están compuestos de este material. En esta serie se encontró que el 93.75% de los litos examinados eran de oxalato de calcio. El 76% de los pacientes con litos de oxalato de calcio son de sexo masculino y presentan una edad promedio de 46.4 años; en los litos compuestos por ácido úrico se encontró una prevalencia del 5% y el 100% de estos eran varones. Los conformados por cistina comprende solo el 1.25% encontrados en el 100% de estos en varones. No se encontraron litos de estruvita. Se concluyó que los pacientes de sexo masculino presentan mayor prevalencia en la formación de litos urinarios.

Modificación de los factores de riesgo cardiovascular en pacientes que se sometieron a intervención quirúrgica cardiaca y motivos asociados al cambio

Antecedentes: La enfermedad cardiovascular en una de las principales causas de muerte en el mundo. Es de suma importancia la modificación de los factores de riesgo cardiovascular posterior a presentar una cardiopatía isquémica y su intervención quirúrgica terapéutica. Objetivos: determinar la cantidad de personas que modificaron los factores de riesgo cardiovascular luego de ser sometido a intervención quirúrgica cardiaca y describir las principales causas que facilitan y obstaculizan el cambio de los factores de riesgo cardiovascular. Métodos: estudio de método mixto, retrospectivo, abierto. Los participantes fueron 90 personas entre 40 y 80 años de edad diagnosticados con cardiopatía isquémica y que fueron sometidos a una intervención quirúrgica cardiaca terapéutica. Resultados: Existe una diferencia estadísticamente significativa entre el puntaje de riesgo cardiovascular previo y post tratamiento quirúrgico. Se encontró que el puntaje de riesgo cardiovascular disminuye 4% a 6 meses después de haber sido sometido a tratamiento quirúrgico. La dieta en el 60% de los pacientes y ejercicio en 35% son los principales factores asociados al cambio. Conclusiones: se demostró que los pacientes disminuyen el puntaje de riesgo cardiovascular luego de haber sido sometidos a una intervención quirúrgica cardiaca.

Oxalate nephropathy in systemic sclerosis: Case series and review of the literature

OBJECTIVE

To increase awareness of oxalate nephropathy as a cause of acute kidney injury (AKI) among systemic sclerosis patients with small intestinal dysmotility and malabsorption, and to prompt consideration of dietary modification and early treatment of predisposing causes of oxalate nephropathy in this population.

METHODS

Two cases of biopsy-proven oxalate nephropathy were identified among systemic sclerosis patients in the course of direct clinical care. Subsequently, a retrospective search of the Johns Hopkins Pathology databases identified a third patient with systemic sclerosis who developed oxalate nephropathy.

RESULTS

Among the three patients with qualifying biopsies, all three had systemic sclerosis with lower gastrointestinal involvement. All three presented with diarrhea, malabsorption, and AKI. In two of the three patients, diarrhea was present for at least 2 years before the development of AKI; in the third, incidental oxalate nephropathy was noted 3 years before she developed AKI and extensive oxalate nephropathy in the setting of a prolonged mycobacterium avium-intracellulare enteritis. In the first case, oxalate crystals were present by urinalysis months before diagnosis by biopsy; in the second, hyperoxaluria was diagnosed by urine collection immediately after; and in the third, oxalate crystals had been noted incidentally on post-transplant renal biopsy 3 years before the development of fulminant oxalate nephropathy. All three patients died within a year after diagnosis.

CONCLUSIONS

Patients with systemic sclerosis and bowel dysmotility associated with chronic diarrhea and malabsorption may be at risk for an associated oxalate nephropathy. Regular screening of systemic sclerosis patients with small bowel malabsorption syndromes through routine urinalysis or 24-h urine oxalate collection, should be considered. Further studies defining the prevalence of this complication in systemic sclerosis, the benefit of dietary modification on hyperoxaluria, the effect of treating small intestinal bowel overgrowth with antibiotics, and the effectiveness of probiotics, calcium supplements, or magnesium supplements to prevent hyperoxaluria-associated renal disease in these patients, are warranted.

Diagnostic utility of attenuation measurement (Hounsfield units) in computed tomography stonogram in predicting the radio-opacity of urinary calculi in plain abdominal radiographs

OBJECTIVE

(1) To determine the best cut-off level of Hounsfield units (HU) in the CT stonogram that would predict the appearance of a urinary calculi in plain KUB X-ray; (2) to estimate the sensitivity and specificity of the best cut-off HU; and (3) to determine whether stone size and location affect the in vivo predictability.

METHODS

A prospective cross-sectional study of patients aged 18-85 diagnosed with urolithiases on CT stonogram with concurrent plain KUB radiograph was conducted. Appearance of stones was recorded, and significant difference between radiolucent and radio-opaque CT attenuation level was determined using ANOVA. Receiver operating characteristics (ROC) curve determined the best HU cut-off value. Stone size and location were used for factor variability analysis.

RESULTS

A total of 184 cases were included in this study, and the average urolithiasis size on CT stonogram was 0.84 cm (0.3-4.9 cm). On KUB X-ray, 34.2 % of the urolithiases were radiolucent and 65.8 % were radio-opaque. Mean value of CT Hounsfield unit for radiolucent stones was 358.25 (±156), and that for radio-opaque stones was 816.51 (±274). ROC curve determined the best cut-off value of HU at 498.5, with the sensitivity of 89.3 % and specificity of 87.3 %. For >4 mm stones, the sensitivity was 91.3 % and the specificity was 81.8 %. On the other hand, for =<4 mm stones, the sensitivity was 60 % and the specificity was 89.5 %.

CONCLUSIONS

Based on the constructed ROC curve, a threshold value of 498.5 HU in CT stonogram was established as cut-off in determining whether a calculus is radio-opaque or radiolucent. The determined overall sensitivity and specificity of the set cut-off HU value are optimal. Stone size but not location affects the sensitivity and specificity.

Fluids and diuretics for acute ureteric colic

BACKGROUND

Acute ureteric colic is commonly associated with severe and debilitating pain. Theoretically, increasing fluid flow through the affected kidney might expedite stone passage, thereby improving symptoms more quickly. The efficacy and safety of interventions such as high volume intravenous (IV) or oral fluids and diuretics aimed at expediting ureteric stone passage is, however, uncertain.

OBJECTIVES

To look at the benefits and harms of diuretics and high volume (above maintenance) IV or oral fluid therapy for treating adult patients presenting with uncomplicated acute ureteric colic.

SEARCH METHODS

We searched the Cochrane Renal Group's specialised register (3 January 2012). Previously we searched the Cochrane Central Register of Controlled Trials (CENTRAL The Cochrane Library), MEDLINE (from 1966), EMBASE (from 1980) and handsearched reference lists of nephrology and urology textbooks, review articles, relevant studies, and abstracts from nephrology scientific meetings.

SELECTION CRITERIA

All randomised controlled trials (RCTs) and quasi-RCTs (including the first period of randomised cross-over studies) looking at diuretics or high volume IV or oral fluids for treating uncomplicated acute ureteric colic in adult patients presenting to the emergency department for the first time during that episode were included.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. Statistical analyses were performed using the random-effects model for multiple studies of the same outcomes, otherwise the fixed-effect model was used. Results were expressed as risk ratios (RR) for dichotomous outcomes or as mean differences (MD) for continuous data with 95% confidence intervals (CI).

MAIN RESULTS

Two studies (enrolling 118 participants) examined the association between intense hydration and ureteric colic outcomes. There was no significant difference in pain at six hours (1 study, 60 participants: RR 1.06, 95% CI 0.71 to 1.57), surgical stone removal (1 study, 60 participants: RR 1.20, 95% CI 0.41 to 3.51) or manipulation by cystoscopy (1 study, 60 participants: RR 0.67, 95% CI 0.21 to 2.13) when no fluids over six hours was compared to three litres IV fluids administered over a six hour period. There was no difference in stone clearance (1 study 43 participants: RR 1.38, 95% CI 0.50 to 3.84), hourly pain score or patients' narcotic requirements (P > 0.05 for all comparisons) when forced IV hydration of two litres over four hours was compared with minimal IV hydration at 20 mL/hour.One study did not provide any details which would have allowed us to assess any of the risk of bias items (selection, detection, performance, attrition or reporting bias). The second study did not report the method of randomisation or allocation (selection bias - unclear), they reported that the patients were blinded to therapy (low risk of bias), analgesics were administered according to predetermined pain score criteria (low risk), and assessment of stone passage was unlikely to have been biased by knowledge of group assignment (low risk). However the second study also reported a high percentage of participants excluded post randomisation (26%; high risk of bias). We were unable to assess or ascertain any of the other risk of bias items.

AUTHORS' CONCLUSIONS

We found no reliable evidence in the literature to support the use of diuretics and high volume fluid therapy for people with acute ureteric colic. However, given the potential positive therapeutic impact of fluids and diuretics to facilitate stone passage, the capacity of these interventions warrants further investigation to determine safety and efficacy profiles.

Epidemiology of pediatric urolithiasis

Pediatric urolithiasis has increased globally in the last few decades. There has been a change in the pattern of stone composition with an increase in the frequency of kidney stones and a decrease in bladder stones. The role of familial predisposition and environmental factors in pediatric urolithiasis is now better understood. Metabolic factors are more common in pediatric urolithiasis than in adult stone disease. This review updates on the epidemiology of pediatric urolithiasis with a focus on the changing trends in the stone disease, current spectrum of stone disease encountered in clinical practice, individual predisposition and the role of environmental factors in stone formation.

History, epidemiology and regional diversities of urolithiasis

Archeological findings give profound evidence that humans have suffered from kidney and bladder stones for centuries. Bladder stones were more prevalent during older ages, but kidney stones became more prevalent during the past 100 years, at least in the more developed countries. Also, treatment options and conservative measures, as well as 'surgical' interventions have also been known for a long time. Our current preventive measures are definitively comparable to those of our predecessors. Stone removal, first lithotomy for bladder stones, followed by transurethral methods, was definitively painful and had severe side effects. Then, as now, the incidence of urolithiasis in a given population was dependent on the geographic area, racial distribution, socio-economic status and dietary habits. Changes in the latter factors during the past decades have affected the incidence and also the site and chemical composition of calculi, with calcium oxalate stones being now the most prevalent. Major differences in frequency of other constituents, particularly uric acid and struvite, reflect eating habits and infection risk factors specific to certain populations. Extensive epidemiological observations have emphasized the importance of nutritional factors in the pathogenesis of urolithiasis, and specific dietary advice is, nowadays, often the most appropriate for prevention and treatment of urolithiasis.

Gender Differences among Hispanics and Caucasians in symptomatic presentation of kidney and ureteral stones

PURPOSE

We determined gender differences in the symptomatic presentation of kidney and ureteral stones among the Hispanic population and compared it with presentation in the Caucasian population.

PATIENTS AND METHODS

A retrospective chart review was performed on 443 patients seen in our Emergency Department or Urgent Care Center for symptomatic kidney or ureteral stones over a 5-year period. Demographic information was obtained, including sex, race, age, location of stone, stone size, and type of urologic intervention. Of the 443 patients, 263 (59%) were Hispanic, and 180 (41%) were Caucasian.

RESULTS

The male-to-female ratio of the symptomatic patients with kidney stones was 1.48 for both Hispanic and Caucasian patients. The male-to-female ratio for ureteral stones was 1.06 and 2.48 for the Hispanic and Caucasian patients, respectively (P < 0.05). The rate of urologic intervention was similar among Caucasian males and females and Hispanic females (approximately 33%) but significantly lower among Hispanic males (18%).

CONCLUSIONS

The relative symptomatic presentation of ureteral stones of men and women among the Hispanic population is nearly 1:1, whereas the ratio in Caucasian men and women approaches the previously reported 2.5:1. No significant racial or sex differences were noted in the symptomatic presentation of kidney stones. In comparison with Hispanic men, Hispanic women undergo significantly more urologic interventions for symptomatic urolithiasis.

Fluids and diuretics for acute ureteric colic

BACKGROUND

Acute ureteric colic is a common cause of severe and debilitating pain. Theoretically, increasing fluid flow through the affected kidney might expedite stone passage, thereby improving symptoms more quickly. Unfortunately, for interventions such as high volume intravenous or oral fluids and diuretics that are aimed at doing this, the efficacy and safety is uncertain.

OBJECTIVES

To look at the benefits and harms of diuretics and high volume (above maintenance) intravenous or oral fluid therapy for treating adult patients presenting with uncomplicated acute ureteric colic.

SEARCH STRATEGY

We searched the Cochrane Renal Group's specialised register (July 2004), the Cochrane Central Register of Controlled Trials (CENTRAL - The Cochrane Library, issue 3, 2004), MEDLINE (1966 - July 2004), EMBASE (1980 - July 2004) and handsearched reference lists of nephrology and urology textbooks, review articles, relevant trials, and abstracts from nephrology scientific meetings. We sent letters seeking information about unpublished or incomplete trials to investigators known to be involved in previous trials.

SELECTION CRITERIA

All randomised controlled trials (RCTs) and quasi-RCTS (including the first period of randomised cross-over studies) looking at diuretics or high volume intravenous or oral fluids for treating uncomplicated acute ureteric colic in adult patients presenting to the emergency department for the first time during that episode were to be included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Statistical analyses were performed using the random effects model and the results expressed as relative risk (RR) for dichotomous outcomes or weight mean difference (WMD) for continuous data with 95% confidence intervals (CI).

MAIN RESULTS

One trial (60 participants) was identified. This study compared no fluids for six hours versus three litres of IV fluids received over a six hour period. There was no significant difference in pain at six hours (RR 1.06, 95% CI 0.71 to 1.57), surgical stone removal (RR 1.20, 95% CI 0.41 to 3.51) or manipulation by cystoscopy (RR 0.67, 95% CI 0.21 to 2.13).

AUTHORS' CONCLUSIONS

Unfortunately, we could find no credible evidence in the literature regarding either of these two treatment modalities. Given their potential positive impact, the role of diuretics and high volume fluid therapy in acute ureteric colic should be examined to determine their safety and efficacy in facilitating stone passage.

Ethnic background has minimal impact on the etiology of nephrolithiasis

PURPOSE

Nephrolithiasis disproportionately affects white patients. However, recent studies propose an increase in the incidence of stone disease in nonwhite populations. We compared the metabolic risk factors of ethnically disparate stone formers from the same geographic region.

MATERIALS AND METHODS

A retrospective review of 1,141 patients identified 98 (9%) nonwhite stone formers. Of these individuals 60 underwent a comprehensive metabolic evaluation, comprising 44 black, 8 Asian and 8 Hispanic patients. A similar sex and age matched group of 66 white stone forming patients were also identified for comparative analysis. Stone analyses were recorded when available. Urinary metabolic abnormalities were defined as low urine volume-urine volume less than 2,000 cc, gouty diathesis-pH 5.5 or less (normal level 5.5 to 6.5), hypercalciuria-calcium greater than 200 mg, hyperoxaluria-oxalate greater than 45 mg, hyperuricosuria-uric acid greater than 600 mg, hypocitraturia-citrate less than 600 mg and purine gluttony-sulfate greater than 20 mg.

RESULTS

The incidence of metabolic abnormalities was surprisingly similar between the white and nonwhite stone formers. Whites have a higher prevalence of hypercalciuria compared with nonwhites (67% vs 25%, respectively, p <0.01). This comparison persisted when the white group was compared with individual ethnic groups (25% in each group). Whites also displayed a higher mean urinary calcium level (233 mg) than their nonwhite counterparts overall (146 mg), specifically with respect to blacks (146 mg, p <0.01). Asians had higher urine volumes with respect to whites and blacks (p <0.01) and, therefore, a decreased prevalence of low urine volumes (37.5% vs 74.2% and 79.5%, respectively). Hypocitraturia, hyperuricosuria, hyperoxaluria, gouty diathesis and high sulfate levels were equally represented among all ethnic groups.

CONCLUSIONS

Although there appears to be a predominance of stone disease among whites, all racial groups demonstrated a remarkable similarity in the incidence of underlying metabolic abnormalities. These results suggest that dietary and environmental factors may be as important as ethnicity in the etiology of stone disease.