ABSTRACT Objective: This study aimed to investigate the association between 25OHD (total, bioavailable and free) with bone mass and microarchitecture among primary hyperparathyroidism (PHPT) patients and controls. Subjects and methods: Sixty-four patients in the preoperative period of PHPT and 63 matched controls, who had not taken vitamin D in the last three months. To calculate the bioavailable and free 25OHD, the genetic variants of the vitamin D-binding protein (DBP) were determined. Bone mineral density (BMD) was determined by dual-energy X-ray absorptiometry (DXA). The distributions of total, bioavailable and free 25OHD and their correlation with TBS and DXA were evaluated. Results: PHPT showed BMD and TBS values lower than CTRL in all locations (p < 0.05). There were no statistical differences in the levels of free, bioavailable and total 25OHD between the PHPT and CTRL groups [mean, min-max: 3.4 (1.4-8.6) vs. 3.1 (1.0-9.8) pg/mL, 1.51 (0.43-3.58) vs. 1.41 (0.38-3.48) ng/mL, 22.6 (11.0-39.9) vs. 20.6 (8.9-35.3) ng/dL, respectively; (p > 0.05). The distribution of DBP haplotypes was similar between groups. DXA showed no correlation with any form of 25OHD in both groups. TBS presented a weak correlation with the total 25OHD in PHPT (r = 0.28; p = 0.02) and a moderate correlation with the total, free and bioavailable 25OHD in CTRL (r = 0.42; r = 0.42; r = 0.43; respectively, p < 0.01). Conclusion: The concentrations of total, free and bioavailable 25OHD were similar in both the PHPT and control groups. 25OHD concentrations correlated positively with TBS and not with DXA, especially in controls, suggesting that this method may be more sensitive to assessing the consequences of vitamin D deficiency on bone quality in individuals without PHPT.

ABSTRACT In recent years the immunomodulatory actions of vitamin D, a steroid hormone, have been extensively studied. In 2020, due to the COVID-19 pandemic, the question arose as to 25(OH)D status would be related to susceptibility to SARS-CoV-2 infection, since several studies pointed out a higher prevalence and severity of the disease in populations with low levels of 25(OH)D. Thus, we investigated the 25(OH)D levels in adults “Detected” positive for SARS CoV-2 by RT-PCR (reverse transcriptase polymerase chain reaction) test, and in negative controls, “not Detected”, using the Fleury Group's examination database, in Sao Paulo, Brazil. Of a total of 14.692 people with recent assessments of 25(OH)D and RT-PCR tests for COVID-19, 2.345 were positive and 11.585 were negative for the infection. The groups did not differ in the percentage of men and women, or in the age distribution. There were no differences in the distribution of 25(OH)D between the two groups (p = 0.08); mean 25(OH)D of 28.8 ± 21.4 ng/mL and 29.6 ± 18.1 ng/mL, respectively. In the specific population studied, clinical, environmental, socioeconomic and cultural factors should have greater relevance than 25(OH)D in determining the susceptibility to COVID-19.

ABSTRACT Objective To measure type 1 serum amino-terminal propeptide procollagen (P1NP) and type 1 cross-linked C-terminal telopeptide collagen (CTX) before parathyroidectomy (PTX) in PHPT patients, correlating these measurements with bone mineral density (BMD) changes. Subjects and methods 31 primary hyperparathyroidism (HPTP) were followed from diagnosis up to 12-18 months after surgery. Serum levels of calcium, parathyroid hormone (PTH) vitamin D, CTX, P1NP, and BMD were measured before and 1 year after surgery. Results One year after PTX, the mean BMD increased by 8.6%, 5.5%, 5.5%, and 2.2% in the lumbar spine, femoral neck (FN), total hip (TH), and distal third of the nondominant radius (R33%), respectively. There was a significant correlation between BMD change 1 year after the PTX and CTX (L1-L4: r = 0.614, p < 0.0003; FN: r = 0.497, p < 0.0051; TH: r = 0.595, p < 0.0005; R33%: r = 0.364, p < 0.043) and P1NP (L1-L4: r = 0,687, p < 0,0001; FN: r = 0,533, p < 0,0024; TH: r = 0,642, p < 0,0001; R33%: r = 0,467, p < 0,0079) preoperative levels. The increase in 25(OH)D levels has no correlation with BMD increase (r = -0.135; p = 0.4816). On linear regression, a minimum preoperative CTX value of 0.331 ng/mL or P1NP of 37.9 ng/mL was associated with a minimum 4% increase in L1-L4 BMD. In TH, minimum preoperative values of 0.684 ng/mL for CTX and 76.0 ng/mL for P1NP were associated with a ≥ 4% increase in BMD. Conclusion PHPT patients presented a significant correlation between preoperative levels of turnover markers and BMD improvement 1 year after PTX.

SUMMARY Identification of the correct etiology of diabetes brings important implications for clinical management. In this report, we describe a case of a 4-year old asymptomatic girl with diabetes since age 2, along with several individuals in her family with different etiologies for hyperglycemia identified in youth. Genetic analyses were made by Sanger sequencing, laboratory measurements included HbA1c, lipid profile, fasting C-peptide, pancreatic auto-antibodies (glutamic acid decarboxylase [GAD], Islet Antigen 2 [IA-2], and anti-insulin). We found a Gly178Ala substitution in exon 5 of GCK gene in three individuals co-segregating with diabetes, and type 1 diabetes was identified in two other individuals based on clinical and laboratory data. One individual with previous gestational diabetes and other with prediabetes were also described. We discuss difficulties in defining etiology of hyperglycemia in youth in clinical practice, especially monogenic forms of diabetes, in spite of the availability of several genetic, laboratory, and clinical tools.

ABSTRACT Measuring thyroid hormones is an important aspect for the study of metabolism and for monitoring diseases in both human and animal models. The traditional method for hormone measurement in rats is the radioimmunoassay (RIA). However, the RIA is associated with some practical disadvantages, including the use of radioactive material, the need for specialized equipment and expert staff, the short shelf-life of kits according to the half-life of the radioisotope and high costs. The objective of this study was to develop a new cost-effective method for measuring TSH levels in rats that avoids the use of radioactive material. We developed an in-house competitive immunoassay using a reference standard, polyclonal antibody produced in rabbits and biotinylated antigen. This method was tested in 64 Wistar rats that were divided into a control group (n = 41) and a group with hypothyroidism (n = 23). Our assay demonstrated an analytical sensitivity of 0.24 ng/mL (n = 12) and an intra-assay coefficient of variation (CV) of 8.9% for sera with TSH levels of 1.5 ng/mL and 13.2% for sera with TSH levels of 17.5 ng/mL (n = 14). The inter-assay CV was 13.5% for sera with TSH levels of 1.4 ng/mL and 14.5% for TSH levels of 18.2 ng/mL (n = 5). The analysis of mean TSH levels in control rats (5.06 ± 0.5701) and hypothyroid rats (51.09 ± 5.136) revealed a statistically significant difference (p < 0.001) between the groups. This method showed good sensitivity, can be automated and is low-cost compared with RIA. Our method offers a viable alternative for TSH measurement in rats.

ABSTRACT Objective To evaluate the usefulness of a third-generation PTH assay in the diagnosis of primary hyperparathyroidism (PHPT). Subjects and methods Forty-one PHPT patients (4 men and 37 women) with 61.2 ± 10.9 (mean ± SD) years, were studied and had PTH levels measured with two different methods using the same immunochemiluminescent assay plataform (Elecsys 2010 System, Roche). We compared a second-generation assay (I-PTH) with a third-generation PTH assay (Bio-PTH). Two populations of 423 and 120 healthy adults with serum 25OHD levels above 25 ng/mL were used to define normal values in the I-PTH and Bio-PTH assays respectively. Results Normal PTH values based in the healthy adults population were 24.2-78.0 pg/mL for the I-PTH assay and 19.9-58.5 pg/mL for Bio-PTH assay. In PHPT patients, PTH values ranged from 67 to 553 pg/mL (median: 168 pg/mL) using the I-PTH assay and from 55 to 328 pg/mL (median: 111 pg/mL) using the Bio-PTH assay. Results obtained with the Bio-PTH assay were significantly lower (p < 0.0001, Wilcoxon). In general I-PTH and Bio-PTH showed highly significant correlation (r = 0.952, p < 0.0001). Passing–Bablok analysis gave a regression equation of Bio PTH = 13.44 + 0.59 x intact PTH. PHPT patients had 25OHD levels ranging from 4 to 36 ng/mL (mean 16.2 ng/mL); 35 subjects (85.3%) had values bellow 25 ng/mL. Conclusion Our results demonstrate that both second and third generation PTH methods are strongly correlated in PHPT patients and control subjects. Lower results with Bio-PTH tests are expected in function of the assay specificity determined by the amino-terminal antibody used.

ABSTRACT Thyroglobulin (Tg) is the major glycoprotein produced by the thyroid gland, where it serves as a template for thyroid hormone synthesis and as an intraglandular store of iodine. Measurement of Tg levels in serum is of great practical importance in the follow-up of differentiated thyroid carcinoma (DTC), a setting in which elevated levels after total thyroidectomy are indicative of residual or recurrent disease. The most recent methods for serum Tg measurement are monoclonal antibody-based and are highly sensitive. However, major challenges remain regarding the interpretation of the results obtained with these immunometric methods, particularly in patients with endogenous antithyroglobulin antibodies or in the presence of heterophile antibodies, which may produce falsely low or high Tg values, respectively. The increased prevalence of antithyroglobulin antibodies in patients with DTC, as compared with the general population, raises the very pertinent possibility that tumor Tg may be more immunogenic. This inference makes sense, as the tumor microenvironment (tumor cells plus normal host cells) is characterized by several changes that could induce posttranslational modification of many proteins, including Tg. Attempts to understand the structure of Tg have been made for several decades, but findings have generally been incomplete due to technical hindrances to analysis of such a large protein (660 kDa). This review article will explore the complex structure of Tg and the potential role of its marked heterogeneity in our understanding of normal thyroid biology and neoplastic processes.

Objective Consuming a low-iodine diet (LID) is a widely accepted practice before administering radioiodine (131I) to evaluate and to treat thyroid disease. Although this procedure is well established for the management of patients with differentiated thyroid cancer, its use in patients with benign disease is unclear. So, we aimed to evaluate the influence of a LID on the outcome in patients with Graves’ disease (GD) treated with131I. Subjects and methods We evaluated 67 patients with GD who were divided into 2 groups: one group (n = 31) consumed a LID for 1-2 weeks, and the second group (n = 36) was instructed to maintain a regular diet (RD). Results The LID group experienced a 23% decrease in urinary iodine after 1 week on the diet and a significant 42% decrease after 2 weeks on the diet. The majority (53%) of the patients in the LID group had urinary iodine levels that were consistent with deficient iodine intake. However, there was no difference in the rate of hyperthyroidism’s cure between the LID and the RD groups 6 months after 131I therapy. Furthermore, the therapeutic efficacy did not differ in patients with varying degrees of sufficient iodine intake (corresponding urinary iodine levels: < 10 μg/dL is deficient; 10-29.9 μg/dL is sufficient; and > 30 μg/dL is excessive). Conclusion In the present study, we demonstrated that although a LID decreased urinary iodine levels, those levels corresponding with sufficient or a mild excess in iodine intake did not compromise the therapeutic efficacy of131I for the treatment of GD.

Objetivo A dosagem de cortisol salivar é uma metodologia que vem tendo crescente aceitação no estudo da função adrenocortical. Sua alta correlação com a fração livre sérica, facilidade de coleta e presença limitada de interferentes têm originado múltiplas publicações, em especial no screening de pacientes suspeitos de hiperfunção. Neste trabalho apresentamos nossa experiência no desenvolvimento de metodologia baseada em cromatografia líquida e espectrometria de massas (HPLC-MS/MS) para a medida de cortisol e cortisona salivares. Materiais e métodos Para este estudo utilizamos 181 amostras de saliva de nossa rotina diagnóstica. A metodologia de HPLC-MS/MS baseou-se num espectrômetro de massas Waters Quattro Premier. Após derivatização com hidroxilamina, as transições monitoradas incluíram cortisol e cortisona. Um radioimunoensaio (RIE) in house foi empregado para comparação. Resultados A sensibilidade funcional para cortisol foi de 24 ng/dL, com linearidade entre 24 e 1,929 ng/dL. Os valores de cortisol obtidos nas 181 amostras apresentaram mediana de 52 ng/dL, com percentis 5‐95% de 24 e 374 ng/dL. Com o RIE, os resultados foram 86, 25 e 436 ng/L, respectivamente, com os valores obtidos no RIE significativamente mais elevados (P<0,0001), e alta correlação (r=0,8312, P<0,0001). Cortisona, medida em 159 amostras, mostrou mediana de 278 ng/dL, com percentis 5‐95% entre 100 e 1.133 ng/dL. A correlação com os valores de cortisol foi significativa (r=0,820, P<0,0001). Conclusão Concluímos que o método baseado em HPLC-MS/MS compara-se favoravelmente com o RIE para a medida de cortisol salivar, com a possibilidade adicional da medida concomitante de cortisona e avaliação da atividade da enzima 11βHSD2.

Objective Salivary cortisol measurement plays an important role in the evaluation of adrenal function. Its high correlation with free serum cortisol, the easy of sampling and the limited presence of interfering steroids, generated multiple recent studies of its application, in special in the screening of adrenal hyperfunction. In this paper we present our experience in the development of a high pressure liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method for salivary cortisol and cortisone measurement. Materials and methods For this study we used 181 saliva samples from our routine diagnostic laboratory. The HPLC-MS/MS method was based on a Waters Quattro Premier tandem mass spectrometer with an electrospray probe. After derivatization with hydroxylamine transitions monitored included cortisol and cortisone. An in-house radioimmunoassay (RIA) was used for salivary cortisol results comparison. Results Functional sensitivity was 24 ng/dL for cortisol and linearity from 24 to 1929 ng/dL. Saliva cortisol values obtained in the 181 samples presented a median of 52 ng/dL with 5‐95% percentile of 24 and 374 ng/dL. With the RIA the results were 86, 25 and 436 ng/dL, respectively, with values for RIA being significantly higher (P<0.0001) and high correlation (r=0.8312, P<0.0001). Cortisone measured in 159 samples showed a median of 278 ng/dL, with 5‐95% percentile of 100 and 1,133 ng/dL. Correlation with cortisol values was significant (r=0.820, P<0.0001). Conclusion We conclude that the HPLC-MS/MS method compares favorably with the RIA for salivary cortisol measurement, with the additional possibility of concomitant cortisone measurement and the evaluation of 11βHSD2 activity.

INTRODUÇÃO: Diversos métodos têm sido propostos com intuito de melhorar índices de sucesso cirúrgico no tratamento do hiperparatiroidismo associado à doença renal crônica (DRC). OBJETIVOS: Avaliar uso do estereomicroscópio na seleção de tecido paratiroideano na paratiroidectomia total com autoimplante em pacientes com DRC. MÉTODOS: 118 pacientes DRC operados entre 04/2000-10/2009 foram divididos em: G1-66 pacientes operados entre 04/2000-05/2005 cuja seleção de tecido foi realizada por método convencional (macroscopia); G2-52 pacientes operados entre 03/2008-10/2009, cuja seleção de tecido foi realizada com uso da estereomicroscopia: Leica-Stereomicroscope (amplificação: 10×-80×). Pacientes foram ainda categorizados em hiperparatiroidismo secundário (HPS) ou terciário (HPT) (HPS-diálise/HPT-transplantados renais). Seguimento pós-operatório: 12-36 meses. PTH intraoperatório medido 100/118 pacientes (84.7%). Todos pacientes foram operados pelo mesmo cirurgião. RESULTADOS: Dados em média. G1, 66 pacientes (38 HPS, 24f/14m; 40 anos; 28 HPT, 14f/14m; 44 anos). G2, 52 pacientes (29 HPS, 11f/18m; 50,7 anos; 23 HPT, 13f/10m; 44,4 anos). Pacientes dialíticos do G2 apresentaram cálcio pré-operatório maior que G1 (p < 0,05), sugerindo doença mais severa. Hipoparatiroidismo definitivo: 7/118 (5,9%) pacientes: G1, 4/66 (6%); G2, 3/52 (5,7%). Recorrência do hiperparatiroidismo no autoimplante: 4 pacientes, 2 em cada grupo. Todas foram em pacientes em diálise. CONCLUSÃO: Estereomicroscopia no tratamento do hiperparatiroidismo associado à DRC é útil na padronização da técnica de seleção de tecido para o autoimplante.

INTRODUCTION: Several methods have been proposed to improve operative success in renal hyperparathyroidism. OBJECTIVE: To evaluate stereomicroscopy in parathyroid tissue selection for total parathyroidectomy with autotransplantation in secondary (SHPT)/tertiary (THPT) hyperparathyroidism. METHODS: 118 renal patients underwent surgery from April of 2000 to October 2009. They were divided into two groups: G1, 66 patients operated from April of 2000 to May of 2005, with tissue selection based on macroscopic observation; G2, 52 patients operated from March of 2008 to October 2009 with stereomicroscopy for tissue selection searching for the presence of adipose cells. All surgeries were performed by the same surgeon. Patients presented SHPT (dialysis treatment) or THPT (renal-grafted). Follow-up was 12-36 months. Intra-operative parathyroid hormone (PTH) was measured in 100/118 (84.7%) patients. RESULTS: Data are presented as means. G1 included 66 patients (38 SHPT, 24 females/14 males; 40.0 years of age; 28 THPT, 14 females/14 males; 44 years of age). G2 included 52 patients (29 SHPT, 11 females/18 males; 50.7 years of age; 23 THPT, 13 females/10 males, 44.4 years of age). SHPT patients from G2 presented preoperative serum calcium higher than those of SHPT patients in G1 (p < 0.05), suggesting a more severe disease. Definitive hypoparathyroidism was found in seven of 118 patients (5.9%). Graft-dependent recurrence occurred in four patients, two in each group. All occurred in dialysis patients. CONCLUSION: Stereomicroscopy in SHPT/THPT surgical treatment may be a useful tool to standardize parathyroid tissue selection.

OBJETIVO: Na última década, estudos mostraram a importância dos ensaios de tiroglobulina (Tg) com melhor sensibilidade funcional no seguimento dos pacientes com carcinoma diferenciado de tiroide (CDT). Neste estudo, descrevemos o desenvolvimento de um novo ensaio de Tg de alta sensibilidade, que foi validado no seguimento de pacientes com CDT e correlacionado com um ensaio comercialmente disponível. SUJEITOS E MÉTODOS: O ensaio imunofluorométrico de Tg baseia-se em anticorpos, um monoclonal e um policlonal desenvolvidos em nosso laboratório. Avaliamos 100 amostras de soro de 87 pacientes com CDT submetidos à tiroidectomia total, sendo que 87% deles também receberam 131I. A Tg foi dosada também em ensaio comercial (Beckman Access). RESULTADOS: A correlação entre os dois métodos foi de 0,74 (p < 0,0001). O novo ensaio mostrou uma sensibilidade funcional de 0,3 ng/mL. A sensibilidade diagnóstica foi de 88,9%, que aumentou para 100% quando associada ao ultrassom cervical (US). CONCLUSÃO: O novo método de dosagem de Tg mostra boa correlação com o ensaio comercial Beckman Access e com a evolução clínica dos pacientes. O novo ensaio será fundamental no seguimento dos nossos pacientes com CDT. Arq Bras Endocrinol Metab. 2012;56(9):658-65

OBJECTIVE: In the last decade, data published stressed the role of highly-sensitive thyroglobulin (Tg) assays in the follow-up of differentiated thyroid carcinoma (DTC) patients. The present study describes a new, highly-sensitive Tg assay, compares it with an available commercial assay, and validates it in the follow-up of DTC patients. SUBJECTS AND METHODS: The immunofluorometric high-sensitivity Tg assay is based on monoclonal and polyclonal antibodies produced at our laboratories. It was validated in 100 samples of 87 patients with DTC submitted to total thyroidectomy, 87% of whom also received radioiodine. For correlation, all samples were also tested using a commercial Tg assay (Beckman Access) with functional sensitivity (FS) of 0.1 ng/mL. RESULTS: The new method showed FS of 0.3 ng/mL. The correlation between the two methods was good (r = 0.74; p < 0.0001). The diagnostic sensitivity was 88.9%, and it was increased to 100% when combined with neck US. CONCLUSION: This new, high-sensitivity Tg assay presented a good correlation with Beckman Access assay and with the clinical outcome of the patients. The continuous availability of a validated assay is an additional advantage for long term follow-up of DTC patients. Arq Bras Endocrinol Metab. 2012;56(9):658-65

INTRODUÇÃO: O teste de supressão com 1 mg de dexametasona (TSDx) é amplamente empregado no rastreamento da síndrome de Cushing (SC) dada sua elevada acurácia diagnóstica. A SC é um distúrbio endocrinometabólico resultante do hipercortisolismo crônico com característica de ausência de supressão do cortisol no TSDx. OBJETIVO: Desenvolver um radioimunoensaio (RIE) para a dosagem de dexametasona (Dx) no soro para complementar o TSDx. MÉTODOS: Foram imunizados três coelhos com o conjugado dexametasona-21-hemissuccinato-BSA para escolha do melhor anticorpo e o RIE foi desenvolvido de acordo com as recomendações da RE 899/2003 da Agência Nacional de Vigilância Sanitária (ANVISA). Analisamos 96 voluntários, sendo 67 submetidos ao TSDx e 29 não, e 12 pacientes com SC, estudados na Universidade Federal de São Paulo (UNIFESP) e na Santa Casa de Misericórdia de São Paulo. RESULTADOS: O anticorpo contra Dx selecionado mostrou boa especificidade, coeficiente de variação (CV%) intra e interensaio < 20%, exatidão de 93,8% e dose mínima detectada de 19,5 ng/dl. A concentração de Dx no soro foi semelhante nos voluntários e pacientes com SC (ausência/supressão do cortisol): 205 a 703 ng/dl e 174 a 661 ng/dl (intervalo de confiança [IC] 95%), respectivamente; os valores foram indetectáveis naqueles que não se submeteram ao teste. DISCUSSÃO: O anticorpo empregado apresenta boa afinidade e especificidade para quantificar a Dx no soro. O RIE mostrou reprodutibilidade e eficiência na determinação dos níveis séricos de Dx durante o TSDx. CONCLUSÃO: O presente RIE para a dosagem de Dx no soro é acurado e confiável, permitindo estabelecer uma faixa de referência de valores para subsidiar a interpretação do TSDx.

INTRODUCTION: The 1 mg dexamethasone suppression test (DxST) is widely used to screen Cushing's syndrome (CS) due to its high diagnostic accuracy. CS is an endocrine-metabolic disorder caused by hypercorticism, which is characterized by the absence of cortisol suppression in DxST. OBJECTIVE: To develop a radioimmunoassay (RIA) for the measurement of serum dexamethasone (Dx) to complement DxST. METHODS: Three rabbits were inoculated with dexamethasone-21-hemisuccinate-BSA in order to choose the best antibody. Serum Dx RIA was performed according to RE 899/2003 (Agência Nacional de Vigilância Sanitária [ANVISA]) regulations. Serum samples from 96 volunteers from Universidade Federal de São Paulo (UNIFESP) and Santa Casa de Misericórdia de São Paulo were analyzed, 67 of which were submitted to DxST and 29 were not. There were 12 patients with CS. RESULTS: The Dx antibody chosen showed good specificity. Intra- and interassay CV were < 20% with 93.8% accuracy and the lowest detection limit was 19.5 ng/dl. Serum Dx concentration was similar among both volunteers and CS patients (absence of cortisol suppression): 205 to 703 ng/dl and 174 to 661 ng/dl (95% CI), respectively. Values were undetectable among those that were not submitted to the test. Discussion: The anti-Dx antibody shows high specificity and reliability to quantify serum Dx in DxST. The Dx RIA presented reproducibility and reliability in the determination of serum Dx levels during DxST. CONCLUSION: The current RIA for serum Dx is accurate and reliable, which permits to establish a reference value range to substantiate DxST interpretation.

OBJETIVO: Avaliar a evolução dos marcadores de metabolismo ósseo (MMO) e da densidade mineral óssea (DMO) após cinco anos de uso de alendronato em mulheres osteoporóticas na pós-menopausa. SUJEITOS E MÉTODOS: 40 pacientes (pct) osteoporóticas, na pós-menopausa, em uso de alendronato (10 mg/dia) por pelo menos 5 anos (Grupo 1 − G1) tiveram o uso do bisfosfonato suspenso. O grupo 2 (G2): 25 mulheres na pós-menopausa, em uso de alendronato (10 mg/dia) há pelo menos 1 ano. Grupo 3 (G3): 23 pct osteoporóticas, controles ainda sem tratamento. G1 e G2 submeteram-se à avaliação da DMO por DXA (basal e após 12 meses de seguimento). Todas as pct colheram amostras basais de CTX e P1NP, e G1 e G2 submeteram-se a coletas trimestrais de CTX e P1NP durante 1 ano. Resultados foram analisados por ANOVA on ranks e Mann-Whitney. RESULTADOS: Níveis médios de DMO não variaram em G1 ou G2 durante o estudo; no entanto, 16 pct (45,7%) no G1 e 1 pct (5,2%) no G2 apresentaram redução clinicamente significativa de DMO (P < 0,001). Níveis basais de CTX e P1NP não diferiram entre G1 e G2, com ambos inferiores aos níveis de G3. Em G1, observou-se elevação significativa de CTX e P1NP após 3 meses. Os níveis de CTX e P1NP em G2 permaneceram estáveis durante todo o seguimento. CONCLUSÃO: Não parece haver supressão excessiva do metabolismo ósseo na prática clínica. A suspensão temporária do alendronato após seu uso prolongado pode não ser segura.

OBJECTIVE: To assess bone turnover markers (BTM) and bone mineral density (BMD) after discontinuation of alendronate treatment used for five or more years. SUBJECTS AND METHODS: 40 patients (pt) with post-menopausal osteoporosis treated with alendronate (10 mg/d) for at least five years (Group 1, G1) had their medication discontinued. Group 2 (G2): 25 pt treated with alendronate for at least one year. Group 3 (G3): 23 treatment-naïve osteoporotic pt. BMD was evaluated in G1 and G2 at baseline and after 12 months. Collagen type I cross-linked C-telopeptide (CTX) and procollagen type 1 N-terminal propeptide (P1NP) levels were measured in all pt at baseline, and in G1 and G2 every three months for 12 months. Data were analyzed using ANOVA on ranks and Mann-Whitney tests. RESULTS: Mean BMD values in G1 and G2 did not differ during follow-up. However, 16 pt (45.7%) in G1 and one (5.2%) in G2 lost BMD (P < 0.001). BTM at baseline was not different between G1 and G2, and both were lower than G3. A significant increase in BTM levels was detected in G1 pt after three months, but not in G2. CONCLUSION: Observed BMD loss and BTM rise after alendronate withdrawal imply that bone turnover was not over suppressed, and alendronate discontinuation may not be safe.