Resumo Introdução: Os distúrbios minerais e ósseos (DMO) estão associados a maior mortalidade em pacientes de diálise. As principais diretrizes relacionadas ao assunto, Kidney Disease Outcomes Quality Initiative (KDOQI) e Kidney Disease: Improving Global Outcomes (KDIGO) foram elaboradas com base em informações publicadas de pacientes em hemodiálise. O objetivo do nosso estudo foi avaliar o impacto do cálcio (Ca), fósforo (P) e paratormônio (PTH) (de acordo com as faixas propostas pelas diretrizes do KDOQI e KDIGO) na mortalidade cardiovascular de pacientes em diálise peritoneal (DP). Métodos: Utilizamos o banco de dados BRAZPDII, um estudo prospectivo observacional multicêntrico, que avaliou participantes de DP entre dezembro de 2004 e janeiro de 2011. Entre os 9.905 participantes incluídos neste banco de dados, analisamos 4.424 que estavam em DP há pelo menos 6 meses. As variáveis de confusão apropriadas foram inseridas no modelo. Os níveis séricos de Ca, P e PTH foram as variáveis de interesse para os fins do presente estudo. Resultados: Encontramos uma associação significativa entre níveis séricos de P elevados, categorizados por KDOQI e KDIGO (P acima de 5,5 mg/dL), e sobrevivência cardiovascular (p < 0,01). Da mesma forma, foi encontrada uma associação convincente entre níveis mais baixos de PTH, categorizados por diretrizes (KDOQI e KDIGO - PTH inferior a 150 pg/mL, p < 0,01), e sobrevivência cardiovascular. Conclusão: Em conclusão, níveis de P acima e PTH abaixo dos valores propostos por KDOQI e KDIGO foram associados à mortalidade cardiovascular em pacientes de DP.

Abstract Introduction: Mineral and bone disorders (MBD) are associated with higher mortality in dialysis patients. The main guidelines related to the subject, Kidney Disease Outcomes Quality Initiative (KDOQI) and Kidney Disease: Improving Global Outcomes (KDIGO), were elaborated based on published information from hemodialysis participants. The aim of our study was to evaluate the impact of calcium (Ca), phosphorus (P), and parathyroid hormone (PTH) (according to guideline ranges from KDOQI and KDIGO) on the cardiovascular mortality of peritoneal dialysis (PD) patients. Methods: We used the BRAZPDII database, an observational multi-centric prospective study, which assessed participants on PD between December 2004 and January 2011. Amongst 9,905 participants included in this database, we analyzed 4424 participants who were on PD for at least 6 months. The appropriate confounding variables were entered into the model. Serum levels of Ca, P, and PTH were the variables of interest for the purposes of the current study. Results: We found a significant association between high P serum levels, categorized by KDOQI and KDIGO (P above 5.5 mg/dL), and cardiovascular survival (p < 0.01). Likewise, a compelling association was found between lower levels of PTH, categorized by guidelines (KDOQI and KDIGO - PTH less than 150 pg/mL, p < 0.01), and cardiovascular survival. Conclusion: In conclusion, levels of P above and PTH below the values proposed by KDOQI and KDIGO were associated with cardiovascular mortality in PD patients.

SUMMARY OBJECTIVE: The parathormone level after parathyroidectomy in dialysis patients are of interest. Low levels may require cryopreserved tissue implantation; however, the resection is necessary in case of recurrence. We analyzed post parathyroidectomy parathormone levels in renal hyperparathyroidism. METHODS: Prospective observation of postoperative parathormone levels over defined periods in a cohort of dialysis patients that underwent total parathyroidectomy and immediate forearm autograft from 2008 to 2010, at a single tertiary care hospital. RESULTS: Of 33 patients, parathormone levels until 36 months could be divided into four patterns. Patients with stable function (Pattern 1) show relatively constant levels after two months (67% of the cases). Early function and later failure (Pattern 2) were an initial function with marked parathormone reduction before one year (18%). Graft recurrence (Pattern 3) showed a progressive increase of parathormone in four cases (12%). Complete graft failure (Pattern 4) was a nonfunctioning implant at any period, which was observed in one patient (3%). Parathormone levels of Pattern 3 became statistically different of Pattern 1 at 36 months. CONCLUSIONS: Patients that underwent the total parathyroidectomy and autograft present four different graft function patterns with a possible varied therapeutic management.

RESUMO Introdução: A radiografia digital (RxD) pode representar uma alternativa adequada para investigar o distúrbio mineral e ósseo (DMO) e a perda de densidade óssea (DO) em modelos de roedores da doença renal crônica (DRC). O objetivo deste estudo foi utilizar a RxD para avaliar a DO em ratos com DRC, e avaliar a correlação entre os achados da RxD e marcadores séricos de DMO e histomorfometria óssea. Métodos: A uremia foi induzida pela alimentação de ratos Wistar com dieta enriquecida com adenina (0,75% por 4 semanas/0,10% por 3 semanas); os resultados foram comparados com um grupo controle nas semanas experimentais 3, 4 e 7. Os seguintes marcadores bioquímicos foram medidos: clearance de creatinina (CCr), fosfato (P), cálcio (Ca), fração excretada de P (FeP), fosfatase alcalina (ALP), fator de crescimento de fibroblastos-23 (FGF-23) e paratormônio (PTH). A imagem da RxD foi obtida e a análise histomorfométrica foi realizada com o fêmur esquerdo. Resultados: como esperado, na semana 7, os ratos urêmicos apresentaram redução do CCr e níveis mais altos de P, FeP e ALP em comparação aos controles. A RxD confirmou a menor DO em animais urêmicos (0,57 ± 0,07 vs. 0,68 ± 0,06 u.a.; p = 0,016) em comparação aos controles no final da semana 7, quando a DMO foi mais proeminente. Uma forma grave de doença óssea de alta renovação celular acompanhou essas mudanças bioquímicas. A DO, medida na RxD foi correlacionada a P (r = -0,81; p = 0,002), ALP (r = -0,69, p = 0,01), PTH (r = -0,83, p = 0,01), OS/BS (r = -0,70 p = 0,02) e Ob.S/BS (r = -0,70; p = 0,02). Conclusão: A DO quantificada por RxD esteve associada às complicações típicas da DMO na DRC e mostrou-se viável na avaliação de alterações ósseas na DRC.

ABSTRACT Introduction: Digital radiography (DRx) may provide a suitable alternative to investigate mineral and bone disorder (MBD) and loss of bone density (BD) in rodent models of chronic kidney disease (CKD). The objective of this study was to use DRx to evaluate BD in CKD rats, and to evaluate the correlation between DRx findings and serum MBD markers and bone histomorphometry. Methods: Uremia was induced by feeding Wistar rats an adenine-enriched diet (0.75% for 4 weeks/0.10% for 3 weeks); outcomes were compared to a control group at experimental weeks 3, 4, and 7. The following biochemical markers were measured: creatinine clearance (CrC), phosphate (P), calcium (Ca), fractional excretion of P (FeP), alkaline phosphatase (ALP), fibroblast growth factor-23 (FGF-23), and parathyroid hormone (PTH). DRx imaging was performed and histomorphometry analysis was conducted using the left femur. Results: As expected, at week 7, uremic rats presented with reduced CrC and higher levels of P, FeP, and ALP compared to controls. DRx confirmed the lower BD in uremic animals (0.57±0.07 vs. 0.68 ± 0.06 a.u.; p = 0.016) compared to controls at the end of week 7, when MBD was more prominent. A severe form of high-turnover bone disease accompanied these biochemical changes. BD measured on DRx correlated to P (r=-0.81; p = 0.002), ALP (r = -0.69, p = 0.01), PTH (r = -0.83, p = 0.01), OS/BS (r = -0.70; p = 0.02), and ObS/BS (r = -0.70; p = 0.02). Conclusion: BD quantified by DRx was associated with the typical complications of MBD in CKD and showed to be viable in the evaluation of bone alterations in CKD.

OBJECTIVES: Recent studies have shown a high prevalence of hypovitaminosis D, defined as a serum 25-hydroxyvitamin D level less than 30 ng/ml, in both healthy populations and patients with chronic kidney disease. Patients undergoing kidney transplant are at an increased risk of skin cancer and are advised to avoid sunlight exposure. Therefore, these patients might share two major risk factors for hypovitaminosis D: chronic kidney disease and low sunlight exposure. This paper describes the prevalence and clinical characteristics of hypovitaminosis D among patients undergoing kidney transplant. METHODS: We evaluated 25-hydroxyvitamin D serum levels in a representative sample of patients undergoing kidney transplant. We sought to determine the prevalence of hypovitaminosis D, compare these patients with a control group, and identify factors associated with hypovitaminosis D (e.g., sunlight exposure and dietary habits). RESULTS: Hypovitaminosis D was found in 79% of patients undergoing kidney transplant, and the major associated factor was low sunlight exposure. These patients had higher creatinine and intact parathyroid hormone serum levels, with 25-hydroxyvitamin D being inversely correlated with intact parathyroid hormone serum levels. Compared with the control group, patients undergoing kidney transplant presented a higher prevalence of 25-hydroxyvitamin D deficiency and lower serum calcium, phosphate and albumin but higher creatinine and intact parathyroid hormone levels. CONCLUSIONS: Our results confirmed the high prevalence of hypovitaminosis D in patients undergoing kidney transplant. Therapeutic strategies such as moderate sunlight exposure and vitamin D supplementation should be seriously considered for this population.

RESUMO Objetivo: analisar as frequências de hipoparatireoidismo e de recidiva do hiperparatireoidismo após paratireoidectomia em pacientes dialíticos de acordo com diferentes classificações existentes. Métodos: estudo retrospectivo de 107 pacientes dialíticos consecutivamente submetidos à paratireoidectomia total com autoenxerto imediato em um hospital terciário no período de 2006 a 2010. A variação dos níveis de PTH no pós-operatório foi estudada ao longo do tempo. Os pacientes foram agrupados de acordo com diferentes metas de níveis de PTH recomendados de acordo com o método de dosagem e pelas sociedades de nefrologia americana, japonesa e de um consórcio internacional de especialistas. Resultados: após a paratireoidectomia, houve redução sustentada da calcemia e fosfatemia. O valor mediano do PTH reduziu-se de 1904pg/ml para 55pg/ml, em 12 meses. Dependendo do nível alvo considerado, a proporção de pacientes abaixo da meta variou entre 17% e 87%. Ao contrário, a proporção de pacientes com níveis acima da meta variou de 3% a 37%. Conclusão: O emprego de diferentes recomendações de níveis de PTH em pacientes dialíticos após paratireoidectomia pode levar a classificações incorretas de hipoparatireoidismo ou hiperparatireoidismo recidivado e implicar em condutas terapêuticas discordantes.

ABSTRACT Objective: to analyze the frequency of hypoparathyroidism and of its recurrence after parathyroidectomy in dialysis patients according to different existing classifications. Methods: we conducted a retrospective study of 107 consecutive dialysis patients undergoing total parathyroidectomy with immediate autograft in a tertiary hospital from 2006 to 2010. We studied the changes in PTH levels in the postoperative period over time. Were grouped patients according to different PTH levels targets recommended according to the dosage method and by the American and Japanese Nephrology Societies, and by an International Experts Consortium. Results: after parathyroidectomy, there was sustained reduction in serum calcium and phosphatemia. The median value of PTH decreased from 1904pg/ml to 55pg/ml in 12 months. Depending on the considered target level, the proportion of patients below the target ranged between 17% and 87%. On the other hand, the proportion of patients with levels above the target ranged from 3% to 37%. Conclusion: the application of different recommendations for PTH levels after parathyroidectomy in dialysis patients may lead to incorrect classifications of hypoparathyroidism or recurrent hyperparathyroidism and resultin discordant therapeutic conducts.