Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Osteoporos Int ; 30(4): 923-927, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30680429

RESUMO

Intervals between dual-energy X-ray absorptiometry (DXA) scans were evaluated in a large cohort of typical clinical practice. Intensive DXA scanning (intervals < 23 months) decreased substantially, from 16.7% in 2006 to 6.7% in 2015. INTRODUCTION: Serial dual-energy X-ray absorptiometry (DXA) measurements are suggested for patients at high risk of fractures. However, little is known about how often DXA testing occurs in clinical practice. METHODS: We examined time intervals between DXA testing for monitoring purpose at two academic medical centers in the US between 2004 and 2017. The primary outcome was the presence of testing intervals < 23 months (termed "intensive DXA testing"). A generalized linear mixed model was used to evaluate the association between selected patient-level clinical factors and intensive DXA testing. RESULTS: Forty-nine thousand four hundred ninety-four DXA tests from 20,200 patients were analyzed. The mean time interval between scans was 36 ± 21 months. Only 11.1% of the repeated DXA testing met the criterion for intensive testing. The percentage of intensive DXA testing dropped from 16.7% in 2006 to 6.7% in 2015 (p for trend < 0.001). After adjusting for age, gender, number of outpatient visits, and calendar year, correlates of intensive DXA testing included a baseline T-score < -2.5 at any anatomic site (OR, 4.8; 95%CI, 4.0-5.7), active use of drugs for osteoporosis (OR, 1.6; 95%CI, 1.3-1.9), and active use of glucocorticoids (OR, 1.3; 95%CI, 1.2-1.4). CONCLUSIONS: The predictors of intensive DXA testing suggest that this practice is used preferentially in patients with multiple risk factors and to monitor the response to pharmacotherapy. However, intensive DXA testing has become less common in real-world clinical practice over the last decade. Further studies are required to better define the optimal use of bone mineral density testing in this vulnerable population.


Assuntos
Absorciometria de Fóton/métodos , Densidade Óssea/fisiologia , Osteoporose/diagnóstico , Prática Profissional/estatística & dados numéricos , Centros Médicos Acadêmicos , Idoso , Densidade Óssea/efeitos dos fármacos , Conservadores da Densidade Óssea/uso terapêutico , Monitoramento de Medicamentos/métodos , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Osteoporose/tratamento farmacológico , Osteoporose/fisiopatologia , Fraturas por Osteoporose/prevenção & controle , Prática Profissional/organização & administração , Estudos Retrospectivos , Fatores de Risco , Fatores de Tempo , Estados Unidos
2.
Osteoporos Int ; 29(2): 323-328, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29167971

RESUMO

In a phase 2 trial of 222 postmenopausal women with osteoporosis aged 55 to 85 years randomized to one of three different doses of abaloparatide-SC, subcutaneous teriparatide, or placebo for 24 weeks, abaloparatide-SC resulted in improvements in skeletal microarchitecture as measured by the trabecular bone score. INTRODUCTION: Subcutaneous abaloparatide (abaloparatide-SC) increases total hip and lumbar spine bone mineral density and reduces vertebral and non-vertebral fractures. In this study, we analyzed the extent to which abaloparatide-SC improves skeletal microarchitecture, assessed indirectly by trabecular bone score (TBS). METHODS: This is a post hoc analysis of a phase 2 trial of 222 postmenopausal women with osteoporosis aged 55 to 85 years randomized to abaloparatide-SC (20, 40, or 80 µg), subcutaneous teriparatide (20 µg), or placebo for 24 weeks. TBS was measured from lumbar spine dual X-ray absorptiometry (DXA) images in 138 women for whom the DXA device was TBS software compatible. Assessments were made at baseline, 12 and 24 weeks. Between-group differences were assessed by generalized estimating equations adjusted for relevant baseline characteristics, and a pre-determined least significant change analysis was performed. RESULTS: After 24 weeks, TBS increased significantly by 2.27, 3.14, and 4.21% versus baseline in participants on 20, 40, and 80 µg abaloparatide-SC daily, respectively, and by 2.21% in those on teriparatide (p < 0.05 for each). The TBS in the placebo group declined by 1.08%. The TBS increase in each treatment group was significantly higher than placebo at 24 weeks (p < 0.0001 for each) after adjustment for age, BMI, and baseline TBS. A dose-response was observed at 24 weeks across the three doses of abaloparatide-SC and placebo (p = 0.02). The increase in TBS in the abaloparatide-SC 80 µg group was significantly greater than TPTD (p < 0.03). CONCLUSIONS: These results are consistent with an effect of abaloparatide-SC to improve lumbar spine skeletal microarchitecture, as assessed by TBS.


Assuntos
Conservadores da Densidade Óssea/administração & dosagem , Densidade Óssea/efeitos dos fármacos , Osteoporose Pós-Menopausa/tratamento farmacológico , Proteína Relacionada ao Hormônio Paratireóideo/administração & dosagem , Absorciometria de Fóton , Idoso , Idoso de 80 Anos ou mais , Conservadores da Densidade Óssea/farmacologia , Conservadores da Densidade Óssea/uso terapêutico , Osso Esponjoso/efeitos dos fármacos , Osso Esponjoso/fisiopatologia , Relação Dose-Resposta a Droga , Método Duplo-Cego , Feminino , Humanos , Injeções Subcutâneas , Vértebras Lombares/fisiopatologia , Pessoa de Meia-Idade , Osteoporose Pós-Menopausa/fisiopatologia , Fraturas por Osteoporose/prevenção & controle , Proteína Relacionada ao Hormônio Paratireóideo/farmacologia , Proteína Relacionada ao Hormônio Paratireóideo/uso terapêutico , Teriparatida/uso terapêutico
3.
Bone ; 95: 20-25, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27840301

RESUMO

BACKGROUND: While changes in biochemical markers of bone turnover (BTM) have been reported to predict changes in bone mineral density (BMD), the relationship between changes in BMD and BTMs with combined antiresorptive/anabolic therapy is unknown. METHODS: In the DATA study, 94 postmenopausal osteoporotic women (ages 51-91) received either teriparatide 20-mcg SC daily, denosumab 60-mg SC every 6months, or both for 2years. Pearson's correlation coefficients (R) were calculated to determine the relationship between baseline and early changes in BTMs (as well as serum sclerostin) and 2-year changes in BMD. RESULTS: In women receiving teriparatide, baseline BTMs did not correlate with 2-year BMD changes though 12-month increases in osteocalcin and P1NP were associated with 2-year increases in spine BMD. In women receiving denosumab, spine and hip BMD gains correlated with both baseline and changes in P1NP and C-telopeptide. In women receiving combined teriparatide/denosumab, while both baseline and decreases in P1NP were associated with spine BMD gains, distal radius increases were associated with less CTX suppression. Neither baseline nor changes in serum sclerostin correlated with BMD in any treatment group. SUMMARY AND CONCLUSIONS: In women treated with teriparatide or denosumab, early BTM changes (increases and decreases, respectively) predict 2-year BMD gains, especially at the spine. In women treated with combined teriparatide/denosumab therapy, BMD increases at the distal radius were associated with less suppression of bone turnover. These results suggest that efficacy of combination therapy at cortical sites such as the radius may depend on residual bone remodeling despite RANKL inhibition.


Assuntos
Densidade Óssea , Remodelação Óssea , Denosumab/farmacologia , Teriparatida/farmacologia , Proteínas Adaptadoras de Transdução de Sinal , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Biomarcadores/metabolismo , Densidade Óssea/efeitos dos fármacos , Proteínas Morfogenéticas Ósseas/sangue , Remodelação Óssea/efeitos dos fármacos , Colágeno Tipo I/sangue , Quimioterapia Combinada , Feminino , Marcadores Genéticos , Humanos , Pessoa de Meia-Idade , Fragmentos de Peptídeos/metabolismo , Peptídeos/sangue , Pró-Colágeno/metabolismo , Coluna Vertebral/fisiopatologia
4.
J Clin Endocrinol Metab ; 101(5): 2023-30, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-26964731

RESUMO

CONTEXT: In postmenopausal osteoporosis, combining denosumab and teriparatide increases hip and spine bone mineral density more than either monotherapy. OBJECTIVE: The objective of the study was to determine the effects of 2 years of combination therapy on bone microarchitecture and estimated strength. DESIGN: This was an open-label, randomized controlled trial. PARTICIPANTS AND METHODS: We performed high-resolution peripheral quantitative computed tomography at the distal tibia and radius in 94 postmenopausal osteoporotic women randomized to 2 years of teriparatide 20 µg sc daily, denosumab 60 mg sc every 6 months, or both. RESULTS: Total volumetric bone mineral density (vBMD) at the radius and tibia, trabecular vBMD at the radius, and cortical vBMD at the tibia all increased more in the combination group than both monotherapy groups (P < .002 for all comparisons with combination). Cortical thickness at the tibia also increased more in the combination group (8.1% ± 4.3%) than both other groups (P < .001). Cortical porosity at both the radius and tibia increased progressively over the 24-month treatment period in the teriparatide group but was stable in both other groups (P < .001 teriparatide vs both other groups). Trabecular vBMD at the tibia increased similarly in all groups, whereas radius trabecular vBMD increased more in the combination group than the other groups (P < .01 for both comparisons). Finite element analysis-estimated strength improved or was maintained by all treatments at both the radius and tibia. CONCLUSIONS: Two years of combined teriparatide and denosumab improves bone microarchitecture and estimated strength more than the individual treatments, particularly in cortical bone. These findings suggest that this regimen may be beneficial in postmenopausal osteoporosis.


Assuntos
Conservadores da Densidade Óssea/farmacologia , Densidade Óssea/efeitos dos fármacos , Denosumab/farmacologia , Osteoporose Pós-Menopausa/tratamento farmacológico , Rádio (Anatomia)/efeitos dos fármacos , Teriparatida/farmacologia , Tíbia/efeitos dos fármacos , Idoso , Conservadores da Densidade Óssea/uso terapêutico , Denosumab/uso terapêutico , Quimioterapia Combinada , Feminino , Humanos , Pessoa de Meia-Idade , Osteoporose Pós-Menopausa/diagnóstico por imagem , Rádio (Anatomia)/diagnóstico por imagem , Teriparatida/uso terapêutico , Tíbia/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Resultado do Tratamento
5.
J Clin Endocrinol Metab ; 86(8): 3654-8, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11502792

RESUMO

Androstenedione is a steroid hormone and the major precursor to testosterone. It is available without prescription and taken with the expectation that it will be converted to testosterone endogenously and increase strength and athletic performance. The metabolism of orally administered testosterone has not been well studied. We randomly assigned 37 healthy men to receive 0, 100, or 300 mg oral androstenedione in a single daily dose for 7 d. Single 8-h urine collections were performed on the day before the start of the androstenedione administration and on d 1 and 7 to assess excretion rates of free and glucuronide- conjugated testosterone, androsterone, etiocholanolone, and dihydrotestosterone. Serum testosterone glucuronide concentrations were measured by frequent blood sampling over 8 h on d 1 in 16 subjects (5 each in the 0 and 100 mg group and 6 in the 300 mg group). In the control group, mean (+/-SE) d 1 and 7 excretion rates for testosterone, androsterone, etiocholanolone, and dihydrotestosterone were 3 +/- 1, 215 +/- 26, 175 +/- 26, and 0.4 +/- 0.1 microg/h, respectively. In the 100 mg group, mean d 1 and 7 excretion rates for testosterone, androsterone, etiocholanolone, and dihydrotestosterone were 47 +/- 11, 3,836 +/- 458, 4,306 +/- 458, and 1.6 +/- 0.2 microg/h, respectively. In the 300 mg group, mean d 1 and 7 excretion rates for testosterone, androsterone, etiocholanolone, and dihydrotestosterone were 115 +/- 39, 8,142 +/- 1,362, 10,070 +/- 1,999, and 7.7 +/- 1.5 microg/h, respectively. Urinary excretion rates of all metabolites were greater in both the 100 and 300 mg groups than in controls (P < 0.0001). Urinary excretion rates of testosterone (P = 0.007), androsterone (P = 0.009), etiocholanolone (P = 0.0005), and dihydrotestosterone (P < 0.0001) were greater in the subjects who received 300 mg androstenedione than in those who received 100 mg. In the treated groups, excretion of free testosterone accounted for less than 0.1% of the total excreted testosterone measured. Serum testosterone glucuronide levels increased significantly during frequent blood sampling in both the 100 and 300 mg groups compared with controls (P = 0.0005 for the 100 mg group; P < 0.0001 for the 300 mg group). The net mean changes in area under the curve for serum testosterone glucuronide were -18 +/- 25%, 579 +/- 572%, and 1267 +/- 1675% in the groups receiving 0, 100, and 300 mg/d androstenedione, respectively. We conclude that the administration of both 100 and 300 mg androstenedione increases the excretion rates of conjugated testosterone, androsterone, etiocholanolone, and dihydrotestosterone and the serum levels of testosterone glucuronide in men. The magnitude of these increases is much greater than the changes observed in serum total testosterone concentrations. These findings demonstrate that orally administered androstenedione is largely metabolized to testosterone glucuronide and other androgen metabolites before release into the general circulation.


Assuntos
Androstenodiona/metabolismo , Administração Oral , Adulto , Androstenodiona/sangue , Androstenodiona/urina , Androsterona/urina , Povo Asiático , População Negra , Di-Hidrotestosterona/urina , Etiocolanolona/urina , Glucuronídeos/sangue , Glucuronídeos/urina , Humanos , Masculino , Testosterona/sangue , Testosterona/urina , Estados Unidos , População Branca
6.
J Clin Endocrinol Metab ; 86(2): 511-6, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11158001

RESUMO

Hypogonadism is associated with osteoporosis in men. GnRH- agonist-induced hypogonadism increases bone turnover and bone loss in men, but the mechanism underlying these changes is unknown. To determine whether gonadal steroid deprivation increases the skeletal sensitivity to PTH or blunts the ability of PTH to promote 1,25-dihydroxyvitamin D formation, we infused human PTH-(1-34) at a dose of 0.55 U/kg.h for 24 h, in 11 men (ages, 50-82 yr) with locally advanced, node-positive, or biochemically recurrent prostate cancer but no evidence of bone metastases. PTH infusions were performed before initiation of GnRH agonist therapy (leuprolide acetate, 22.5 mg im, every 3 months) and again after 6 months of confirmed GnRH agonist-induced hypogonadism. Serum osteocalcin (OC), bone- specific alkaline phosphatase (BSAP), N-telopeptide (NTX), whole-blood ionized calcium, and 1,25-dihydroxyvitamin D were measured at baseline and every 6 h during each PTH infusion. Urinary NTX and free deoxypyridinoline (DPD) were assessed on spot morning samples before PTH infusion and on 24-h samples collected during the PTH infusions. Sex steroid levels were lowered to the castrate range in all subjects. Baseline serum NTX levels (drawn before PTH infusion) increased from 9.1 +/- 3.7 before leuprolide therapy to 13.9 +/- 5.0 nmol bone collagen equivalents (BCE)/L after leuprolide therapy (P = 0.003). Spot urine NTX collected before PTH infusion increased from 28 +/- 8 before leuprolide therapy to 49 +/- 17 nmol BCE/mmol creatinine after leuprolide therapy (P < 0.001), and urinary DPD increased from 4.7 +/- 1.1 to 7.4 +/- 1.8 nmol BCE/mmol creatinine (P < 0.001). Baseline serum OC and BSAP levels drawn before each PTH infusion did not change before vs. after leuprolide therapy. Serum NTX levels increased significantly during PTH infusion pre-GnRH agonist therapy (P < 0.001), and the rate of increase was greater after 6 months of GnRH agonist-induced hypogonadism (P < 0.01 for the difference in rates of change before and after GnRH agonist administration). Serum OC and BSAP levels decreased during PTH infusion (P < 0.001 for OC and P = 0.002 for BSAP), but the rates of decrease did not differ before or after leuprolide therapy (P = 0.45 for OC and P: = 0.19 for BSAP). Whole-blood ionized calcium levels increased during PTH infusion (P < 0.001), and the rate of increase was greater after GnRH agonist-induced hypogonadism (P = 0.068). Serum 1,25-dihydroxyvitamin D levels increased in response to PTH infusion before leuprolide therapy (P = 0.022), but there was no difference in the rate of increase before or after leuprolide therapy (P = 0.66). The incremental increase in urinary NTX excretion, but not DPD, during PTH infusion was greater after 6 months of leuprolide therapy (P = 0.029 for NTX, P = 0.578 for DPD). We conclude that suppression of sex steroids in elderly men increases the skeletal responsiveness to the bone resorbing effects of PTH infusion but does not affect the response of bone formation markers or 1,25-dihydroxyvitamin D to PTH. Changes in skeletal sensitivity to PTH may play an important role in the pathogenesis of hypogonadal bone loss in men.


Assuntos
Osso e Ossos/fisiopatologia , Leuprolida/uso terapêutico , Neoplasias da Próstata/fisiopatologia , Teriparatida , Idoso , Idoso de 80 Anos ou mais , Fosfatase Alcalina/sangue , Aminoácidos/urina , Antineoplásicos Hormonais/efeitos adversos , Antineoplásicos Hormonais/uso terapêutico , Biomarcadores/sangue , Biomarcadores/urina , Osso e Ossos/efeitos dos fármacos , Calcitriol/sangue , Cálcio/sangue , Colágeno/sangue , Colágeno/urina , Colágeno Tipo I , Difosfonatos/uso terapêutico , Humanos , Hipogonadismo/sangue , Hipogonadismo/induzido quimicamente , Leuprolida/efeitos adversos , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/tratamento farmacológico , Recidiva Local de Neoplasia/patologia , Recidiva Local de Neoplasia/fisiopatologia , Osteocalcina/sangue , Pamidronato , Peptídeos/sangue , Peptídeos/urina , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/patologia , Fatores de Tempo
7.
JAMA ; 284(20): 2618-21, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11086369

RESUMO

CONTEXT: Several anabolic steroids are sold over-the-counter (OTC) in the United States, and their production is not regulated by the US Food and Drug Administration. Reports have suggested that use of these supplements can cause positive urine test results for metabolites of the prohibited steroid nandrolone. OBJECTIVES: To assess the content and purity of OTC androstenedione and to determine if androstenedione and 19-norandrostenedione administration causes positive urine test results for 19-norandrosterone, a nandrolone metabolite. DESIGN: Randomized controlled trial of androstenedione, open-label trial of 19-norandrostenedione, and mass spectrometry of androstenedione preparations, conducted between October 1998 and April 2000. SETTING: Outpatient facility of a university hospital. PARTICIPANTS: A total of 41 healthy men aged 20 to 44 years. INTERVENTION: Participants were randomly assigned to receive oral androstenedione, 100 mg/d (n = 13) or 300 mg/d (n = 11) for 7 days, or no androstenedione (n = 13); in addition, 4 patients received 10 microg of 19-norandrostenedione. MAIN OUTCOME MEASURES: Content of OTC androstenedione preparations; level of 19-norandrosterone in urine samples, determined by mass spectrometry, compared among the 3 randomized groups at day 1 and day 7, and among the participants who received 19-norandrostenedione from October 1998 to April 2000. RESULTS: All urine samples from participants treated with androstenedione contained 19-norandrosterone, while no samples from the no-androstenedione group did. Urinary concentrations were averaged for day 1 vs day 7 measurements; mean (SD) 19-norandrosterone concentrations in the 100-mg/d and 300-mg/d groups were 3.8 (2.5) ng/mL and 10.2 (6.9) ng/mL, respectively (P =. 006). The 19-norandrosterone content exceeded the cutoff for reporting positive cases (>2.0 ng/mL) in 20 of 24. The androstenedione preparation used was pure at a sensitivity of 0.1%, but at 0.001% 19-norandrostenedione was found. For the 4 participants to whom 10 microg of 19-norandrostenedione was administered, 19-norandrosterone was found in all urine samples. Of 7 brands of androstenedione analyzed at the 1% level, 1 contained no androstenedione, 1 contained 10 mg of testosterone, and 4 more contained 90% or less of the amount stated on the label. CONCLUSION: Our study suggests that trace contamination of androstenedione with 19-norandrostenedione is sufficient to cause urine test results positive for 19-norandrosterone, the standard marker for nandrolone use. Oral steroid doses as small as 10 microg are absorbed and excreted in urine. Some brands of androstenedione are grossly mislabeled. Careful analysis of androstenedione preparations is recommended in all studies of its biological effects. JAMA. 2000;284:2618-2621.


Assuntos
Anabolizantes/metabolismo , Androstenodiona/análogos & derivados , Androstenodiona/metabolismo , Contaminação de Medicamentos , Estranos/urina , Nandrolona/metabolismo , Medicamentos sem Prescrição , Adulto , Androstenodiona/química , Androstenodiona/farmacologia , Suplementos Nutricionais , Humanos , Masculino , Espectrometria de Massas , Detecção do Abuso de Substâncias , Estados Unidos , Urinálise
9.
JAMA ; 283(6): 779-82, 2000 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-10683057

RESUMO

CONTEXT: Androstenedione, a steroid hormone and the major precursor to testosterone, is available without prescription and is purported to increase strength and athletic performance. The hormonal effects of androstenedione, however, are unknown. OBJECTIVE: To determine if oral administration of androstenedione increases serum testosterone levels in healthy men. DESIGN: Open-label randomized controlled trial conducted between October 1998 and April 1999. SETTING: General clinical research center of a tertiary-care, university-affiliated hospital. PARTICIPANTS: Forty-two healthy men aged 20 to 40 years. INTERVENTION: Subjects were randomized to receive oral androstenedione (either 100 mg/d [n = 15] or 300 mg/d [n = 14]) or no androstenedione (n = 13) for 7 days. MAIN OUTCOME MEASURES: Changes in serum testosterone, androstenedione, estrone, and estradiol levels, measured by frequent blood sampling, compared among the 3 treatment groups. RESULTS: Mean (SE) changes in the area under the curve (AUC) for serum testosterone concentrations were -2% (7%), -4% (4%), and 34% (14%) in the groups receiving 0, 100, and 300 mg/d of androstenedione, respectively. When compared with the control group, the change in testosterone AUC was significant for the 300-mg/d group (P<.001) but not for the 100-mg/d group (P = .48). Baseline testosterone levels, drawn 24 hours after androstenedione administration, did not change. Mean (SE) changes in the AUC for serum estradiol concentrations were 4% (6%), 42% (12%), and 128% (24%) in the groups receiving 0, 100, and 300 mg/d of androstenedione, respectively. When compared with the control group, the change in the estradiol AUC was significant for both the 300-mg/d (P<.001) and 100-mg/d (P = .002) groups. There was marked variability in individual responses for all measured sex steroids. CONCLUSIONS: Our data suggest that oral androstenedione, when given in dosages of 300 mg/d, increases serum testosterone and estradiol concentrations in some healthy men.


Assuntos
Androstenodiona/farmacologia , Testosterona/sangue , Administração Oral , Adulto , Androstenodiona/administração & dosagem , Androstenodiona/sangue , Área Sob a Curva , Estradiol/sangue , Estrona/sangue , Humanos , Masculino , Testosterona/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...