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UNLABELLED: Hemodialyzed patients have decreased bone strength not completely characterized. We evaluated bone microarchitecture in hemodialysis patients and compared it to that of subjects without renal disease by high-resolution peripheral quantitative computed tomography (HR-pQCT). Hemodialysis patients have a marked decreased in cortical density, thickness, and area with significant reduction in trabecular parameters that correlated with the severity of secondary hyperparathyroidism only in women. INTRODUCTION: Although fracture risk is greatly increased in dialysis patients, the corresponding decreased in bone strength has not been completely characterized. METHODS: We evaluated volumetric bone mineral density (vBMD) and bone microstructure by HR-pQCT at the distal radius and tibia in 50 hemodialyzed (HD) patients (30 females, mean age 53.2 ± 6 years and 20 males, mean age 59.1 ± 11 years) and 50 sex- and age-matched controls. RESULTS: At the distal radius HD, women showed a 29% reduction in total and trabecular density and trabecular bone volume fraction (p < 0.0001) compared to controls. Trabecular number was reduced by 25% (p < 0.0001), while trabecular separation was increased by 51%. Cortical thickness (-40%, p < 0.0001) and cortical area (-42%, p < 0.0001) were the parameters most reduced, while compact density was the parameter least reduced (-15%, p < 0.0001). Similar findings were found at the tibia. In HD men, HR-pQCT at the distal radius and tibia showed a reduction in volumetric density and microstructure parameters to a lesser extent than in women. In the hemodialyzed group, cortical thickness at the radius was negatively correlated with age both in women and men. At the distal radius and tibia, we found significant negative correlations between Log iPTH and total alkaline phosphatase with cortical vBMD(r = -0.48, p < 0.01; r = -0.69, p < 0.001), thickness (-0.37, p < 0.05; r = -0.60, p < 0.001), and area ((r = -0.43, p = 0.02; r = -0.65, p < 0.001) but only in women. CONCLUSION: We conclude that hemodialysis patients have a marked decreased in cortical density, thickness, and area with significant reduction in trabecular parameters that correlated with the severity of secondary hyperparathyroidism only in women.

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El propósito de este estudio fue evaluar la prevalencia de litiasis renal en la población de la Ciudad de Buenos Aires. Se obtuvo una muestra probabilística de viviendas, y en cada vivienda se encuestó a todos los habitantes de ambos sexos y todas las edades, por medio de un Formulario Epidemiológico estructurado anónimo autoadministrado, averiguando sexo, edad, y si tenían o habían tenido antes una evidencia de padecer litiasis renal; para afirmar la existencia de litiasis se incluyeron otros datos confirmatorios. De 1086 encuestados 43 contestaron tener o haber tenido cálculos, todos ellos por haber recibido diagnóstico médico y además algunos por ver el cálculo al ser eliminado. Hubo diferencia en la tasa de prevalencia según sexo, con valores mayores en los varones, pero la diferencia no fue estadísticamente significativa. No se encontraron personas con litiasis en edades inferiores a los 20 años.

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El propósito de este estudio fue evaluar la prevalencia de litiasis renal en la población de la Ciudad de Buenos Aires. Se obtuvo una muestra probabilística de viviendas, y en cada vivienda se encuestó a todos los habitantes de ambos sexos y todas las edades, por medio de un Formulario Epidemiológico estructurado anónimo autoadministrado, averiguando sexo, edad, y si tenían o habían tenido antes una evidencia de padecer litiasis renal; para afirmar la existencia de litiasis se incluyeron otros datos confirmatorios. De 1086 encuestados 43 contestaron tener o haber tenido cálculos, todos ellos por haber recibido diagnóstico médico y además algunos por ver el cálculo al ser eliminado. Hubo diferencia en la tasa de prevalencia según sexo, con valores mayores en los varones, pero la diferencia no fue estadísticamente significativa. No se encontraron personas con litiasis en edades inferiores a los 20 años. (AU)

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There are little doubts about the need of studying thoroughly every patient with recurrent renal lithiasis. However, the behavior to be followed after the first renal calculi remains controversial. For that reason, we decided to answer a series of questions after which, we formulate our own criteria: Which is the recurrence rate after the first calculi? Has a patient with recurrent lithiasis, the same metabolic disarrangement as a patient who has his first episode? Is the family history of both kidney stone patients the same? Which is the morbility of both groups? We answered these questions with data drawn from 200 of our patients (100 with first episode and 100 with recurrent lithiasis) and a review of the medical literature. The patients with their first episode of lithiasis correspond to the same population of patients with recurrent episodes, but they are detected at different moments of their stone disease. This was concluded since both groups of patients had the same metabolic disarrangement with predominance of hypercalciuria and alteration in uric acid metabolism. Furthermore, the family history was practically the same in both groups (39% in first episode, 41% in recurrent lithiasis) and so was the morbility. Therefore, we propose the following conduct: 1. every patient with renal lithiasis should be studied starting at the first episode, from the urological and metabolic point of view; 2. the initial metabolic studies have to be as extensive as possible in order to aim for specific treatment from the start in order to prevent a recurrence, and in the case of hypercalciuric patients to prevent secondary osteopenia.

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RESUMEN

There are little doubts about the need of studying thoroughly every patient with recurrent renal lithiasis. However, the behavior to be followed after the first renal calculi remains controversial. For that reason, we decided to answer a series of questions after which, we formulate our own criteria: Which is the recurrence rate after the first calculi? Has a patient with recurrent lithiasis, the same metabolic disarrangement as a patient who has his first episode? Is the family history of both kidney stone patients the same? Which is the morbility of both groups? We answered these questions with data drawn from 200 of our patients (100 with first episode and 100 with recurrent lithiasis) and a review of the medical literature. The patients with their first episode of lithiasis correspond to the same population of patients with recurrent episodes, but they are detected at different moments of their stone disease. This was concluded since both groups of patients had the same metabolic disarrangement with predominance of hypercalciuria and alteration in uric acid metabolism. Furthermore, the family history was practically the same in both groups (39

in first episode, 41

in recurrent lithiasis) and so was the morbility. Therefore, we propose the following conduct: 1. every patient with renal lithiasis should be studied starting at the first episode, from the urological and metabolic point of view; 2. the initial metabolic studies have to be as extensive as possible in order to aim for specific treatment from the start in order to prevent a recurrence, and in the case of hypercalciuric patients to prevent secondary osteopenia.