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1.
Artigo em Inglês | MEDLINE | ID: mdl-38837730

RESUMO

BACKGROUND: Same day discharge (SDD) following atrial fibrillation (AF) ablation procedure has emerged as routine practice, and primarily driven by operator discretion. However, the impacts of SDD on clinical outcomes, healthcare system costs, and patient reported outcomes (PROs) have not been systematically studied. METHODS: We retrospectively analyzed patients undergoing routine AF ablation procedures with SDD versus overnight observation (NSDD). After propensity adjustment we compared postprocedure adverse events (AEs), healthcare system costs, and changes in PROs. RESULTS: We identified 310 cases, with 159 undergoing SDD and 151 staying at least one midnight in the hospital (NSDD). Compared with NSDD, SDD patients were similar age (mean 64 vs. 66, p = 0.3), sex (26% female vs. 27%, p = 0.8), and with lower mean CHADS2-VA2Sc scores (2.0 vs. 2.7; p < 0.011). The primary outcome of AEs was noninferior in SDD versus NSDD patients (odds ratio 0.45, 95% confidence interval 0.21-0.99; noninferiority margin of 10%). There were also no differences in overall cost to the healthcare system between SDD and NSDD (p = 0.11). PROs numerically favored SDD (p = NS for all scores). CONCLUSIONS: Physician selection for SDD appears at least as safe as NSDD with respect to clinical outcomes and SDD is not significantly less costly to the health system. There is a trend towards more favorable, general PROs among SDD patients. Routine SDD should be strongly considered for patients undergoing routine AF ablation procedures.

2.
Antivir Ther ; 27(4): 13596535221094898, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-36000318

RESUMO

BACKGROUND: Data on low bone mineral density (BMD) in people living with HIV (PLWH) are mainly derived from younger adults; little is known about how antiretroviral therapy (ART) and alterations in the renal-bone axis relate to BMD in older PLWH. METHODS: Cross-sectional study of men > 50 years and post-menopausal women with HIV. Antiretroviral therapy exposure was stratified into four groups based on use of tenofovir disoproxil fumarate (TDF) and protease inhibitors (PI): non-TDF/non-PI, non-TDF/PI, TDF/non-PI, and TDF/PI. Bone mineral density was measured by dual X-ray absorptiometry (DXA). Bone turnover/regulatory markers and renal tubular function were analysed in stored plasma and urine samples. The association of ART exposure and bone/renal biomarkers on BMD was explored using logistic regression models. RESULTS: 247 individuals (median [IQR] age 57 [53, 65] years; 47% female; 13% of Black ethnicity; CD4 count 643 [473, 811] cells/mm3; and 98% with HIV RNA < 200 copies/mL) were included. Bone turnover and renal tubular function differed significantly by ART exposure. In analyses adjusted for demographic and traditional renal/bone risk factors, exposure to TDF and PI was associated with a fourfold greater risk of low BMD at the femoral neck and exposure to TDF and/or PI with a threefold greater risk of low BMD at the lumbar spine. The relationship between ART and low BMD was not altered by further adjustment for bone turnover or renal tubular function markers. CONCLUSIONS: The associations between low BMD and ART exposure (TDF vs. non-TDF and boosted vs. unboosted third agents) were minimally affected by adjustments for bone and kidney biomarkers.


Assuntos
Fármacos Anti-HIV , Infecções por HIV , Adulto , Idoso , Fármacos Anti-HIV/efeitos adversos , Antirretrovirais/efeitos adversos , Biomarcadores , Densidade Óssea , Estudos Transversais , Feminino , Infecções por HIV/complicações , Humanos , Rim , Masculino , Pessoa de Meia-Idade , Tenofovir/efeitos adversos
3.
Breast Cancer Res Treat ; 168(1): 69-77, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29128898

RESUMO

BACKGROUND: The 21-gene recurrence score (RS) predicts outcome and benefit from adjuvant chemotherapy benefit in breast cancer patients treated with adjuvant endocrine therapy. In the NSABP B-28 study, we evaluated the 21-gene RS for its prognostic impact and its ability to predict benefit from paclitaxel (P) in node-positive, estrogen receptor-positive (ER+) breast cancer patients treated with adjuvant chemotherapy plus tamoxifen. METHODS: The B-28 trial compared doxorubicin/cyclophosphamide (AC) with AC followed by P in 3060 patients. Tamoxifen for 5 years was also given to patients > 50 years and those < 50 years with ER+ and/or progesterone receptor-positive (PR+) tumors. The present study includes 1065 ER-positive, tamoxifen-treated patients with RS assessment. Median follow-up time was 11.2 years. RESULTS: In univariate analyses, RS was a significant predictor of outcome. In multivariate analyses, RS remained a significant independent predictor of outcome beyond clinico-pathologic factors, age, and type of surgery (p < 0.001). In the study population (n = 1065), the disease-free survival (DFS) hazard ratio (HR) with adding P to AC was 0.87 (95% CI 0.72-1.05; p = 0.14). RS was not a significant predictor of P benefit: for DFS, HRs for adding P to AC in RS low, intermediate, and high subgroups were 1.01 (95% CI 0.69-1.47; p = 0.99), 0.84 (95% CI 0.62-1.14; p = 0.26), and 0.81 (95% CI 0.60-1.10; p = 0.21), respectively (interaction p = 0.64). Similar findings were observed for the other study endpoints. CONCLUSIONS: RS maintains significant prognostic impact in ER-positive, node-positive patients treated with adjuvant chemotherapy plus tamoxifen. However, RS did not significantly predict benefit from adding paclitaxel to AC chemotherapy. (Trial Registration: PDQ: NSABP-B-28).


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Biomarcadores Tumorais/genética , Neoplasias da Mama/tratamento farmacológico , Recidiva Local de Neoplasia/genética , Mama/patologia , Mama/cirurgia , Neoplasias da Mama/genética , Neoplasias da Mama/mortalidade , Neoplasias da Mama/patologia , Quimioterapia Adjuvante/métodos , Ciclofosfamida/uso terapêutico , Intervalo Livre de Doença , Doxorrubicina/uso terapêutico , Feminino , Seguimentos , Testes Genéticos/métodos , Humanos , Estimativa de Kaplan-Meier , Metástase Linfática/patologia , Mastectomia , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/diagnóstico , Recidiva Local de Neoplasia/patologia , Recidiva Local de Neoplasia/prevenção & controle , Paclitaxel/uso terapêutico , Prognóstico , Receptores de Estrogênio/metabolismo , Receptores de Progesterona/metabolismo , Tamoxifeno/uso terapêutico
4.
J Natl Cancer Inst ; 109(4)2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-28122895

RESUMO

Background: The 21-gene recurrence score (RS) predicts risk of locoregional recurrence (LRR) in node-negative, estrogen receptor (ER)-positive breast cancer. We evaluated the association between RS and LRR in node-positive, ER-positive patients treated with adjuvant chemotherapy plus tamoxifen in National Surgical Adjuvant Breast and Bowel Project B-28. Methods: B-28 compared doxorubicin/cyclophosphamide (AC X 4) with AC X 4 followed by paclitaxel X 4. Tamoxifen was given to patients age 50 years or older and those younger than age 50 years with ER-positive and/or progesterone receptor-positive tumors. Lumpectomy patients received breast radiotherapy. Mastectomy patients received no radiotherapy. The present study includes 1065 ER-positive, tamoxifen-treated patients with RS assessment. Cumulative incidence functions and subdistribution hazard regression models were used for LRR to account for competing risks including distant recurrence, second primary cancers, and death from other causes. Median follow-up was 11.2 years. All statistical tests were one-sided. Results: There were 80 LRRs (7.5%) as first events (68% local/32% regional). RS was low: 36.2%; intermediate: 34.2%; and high: 29.6%. RS was a statistically significant predictor of LRR in univariate analyses (10-year cumulative incidence of LRR = 3.3%, 7.2%, and 12.2% for low, intermediate, and high RS, respectively, P < .001). In multivariable regression analysis, RS remained an independent predictor of LRR (hazard ratio [HR] = 2.59, 95% confidence interval [CI] = 1.28 to 5.26, for a 50-point difference, P = .008) along with pathologic nodal status (HR = 1.91, 95% CI = 1.20 to 3.03, for four or more vs one to three positive nodes, P = .006) and tumor size (HR = 1.28, 95% CI = 1.05 to 1.55, for a 1 cm difference, P = .02). Conclusions: RS statistically significantly predicts risk of LRR in node-positive, ER-positive breast cancer patients after adjuvant chemotherapy plus tamoxifen. These findings can help in the selection of appropriate candidates for comprehensive radiotherapy.


Assuntos
Neoplasias da Mama/genética , Neoplasias da Mama/terapia , Recidiva Local de Neoplasia/genética , Protocolos de Quimioterapia Combinada Antineoplásica , Neoplasias da Mama/química , Neoplasias da Mama/patologia , Quimioterapia Adjuvante , Ciclofosfamida/administração & dosagem , Doxorrubicina/administração & dosagem , Feminino , Seguimentos , Humanos , Metástase Linfática , Mastectomia Segmentar , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/patologia , Paclitaxel/administração & dosagem , Valor Preditivo dos Testes , Radioterapia Adjuvante , Receptores de Estrogênio/análise , Receptores de Progesterona/análise , Estudos Retrospectivos , Fatores de Risco , Tamoxifeno/administração & dosagem , Carga Tumoral
5.
J Clin Oncol ; 34(20): 2350-8, 2016 07 10.
Artigo em Inglês | MEDLINE | ID: mdl-27217450

RESUMO

PURPOSE: We determined the utility of the 21-Gene Recurrence Score (RS) in predicting late (> 5 years) distant recurrence (LDR) in stage I and II breast cancer within high and low-ESR1-expressing groups. PATIENTS AND METHODS: RS was assessed in chemotherapy/tamoxifen-treated, estrogen receptor (ER) -positive, node-positive National Surgical Adjuvant Breast and Bowel Project B-28 patients and tamoxifen-treated, ER-positive, node-negative B-14 patients. The association of the RS with risk of distant recurrence (DR) 0 to 5 years and those at risk > 5 years was assessed. An ESR1 expression cut point was optimized in B-28 and tested in B-14. RESULTS: Median follow-up was 11.2 years for B-28 and 13.9 years for B-14. Of 1,065 B-28 patients, 36% had low (< 18), 34% intermediate (18 to 30), and 30% high (≥ 31) RS. Of 668 B-14 patients, 51% had low, 22% intermediate, and 27% high RS. Median ESR1 expression by reverse transcriptase polymerase chain reaction was: B-28, 9.7 normalized expression cycle threshold units (CT) and B-14, 10.7 CT. In B-28, RS was associated with DR 0 to 5 years (log-rank P < .001) and > 5 to 10 years (log-rank P = .02) regardless of ESR1 expression. An ESR1 expression cut point of 9.1 CT was identified in B-28. It was validated in B-14 patients for whom the RS was associated with DR in years 5 to 15: 6.8% (95% CI, 4.4% to 10.6%) versus 11.2% (95% CI, 6.2% to 19.9%) versus 16.4% (95% CI, 10.2% to 25.7%) for RS < 18, RS 18 to 30, and RS ≥ 31, respectively (log-rank P = .01). CONCLUSION: For LDR, RS is strongly prognostic in patients with higher quantitative ESR1. Risk of LDR is relatively low for patients with low RS. These results suggest the value of extended tamoxifen therapy merits evaluation in patients with intermediate and high RS with higher ESR1 expression at initial diagnosis.


Assuntos
Neoplasias da Mama/tratamento farmacológico , Receptor alfa de Estrogênio/análise , Recidiva Local de Neoplasia/etiologia , Tamoxifeno/uso terapêutico , Adulto , Idoso , Neoplasias da Mama/química , Neoplasias da Mama/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Prognóstico , Risco
6.
Breast Cancer Res ; 17(1): 133, 2015 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-26429296

RESUMO

INTRODUCTION: The N9831 trial demonstrated the efficacy of adjuvant trastuzumab for patients with human epidermal growth factor receptor 2 (HER2) locally positive tumors by protein or gene analysis. We used the 21-gene assay to examine the association of quantitative HER2 messenger RNA (mRNA) gene expression and benefit from trastuzumab. METHODS: N9831 tested the addition of trastuzumab to chemotherapy in stage I-III HER2-positive breast cancer. For two of the arms of the trial, doxorubicin and cyclophosphamide followed by paclitaxel (AC-T) and doxorubicin and cyclophosphamide followed by paclitaxel and trastuzumab concurrent chemotherapy-trastuzumab (AC-TH), recurrence score (RS) and HER2 mRNA expression were determined by the 21-gene assay (Oncotype DX®) (negative <10.7, equivocal 10.7 to <11.5, and positive ≥11.5 log2 expression units). Cox regression was used to assess the association of HER2 expression with trastuzumab benefit in preventing distant recurrence. RESULTS: Median follow-up was 7.4 years. Of 1,940 total patients, 901 had consent and sufficient tissue. HER2 by reverse transcriptase polymerase chain reaction (RT-PCR) was negative in 130 (14 %), equivocal in 85 (9 %), and positive in 686 (76 %) patients. Concordance between HER2 assessments was 95 % for RT-PCR versus central immunohistochemistry (IHC) (>10 % positive cells = positive), 91 % for RT-PCR versus central fluorescence in situ hybridization (FISH) (≥2.0 = positive) and 94 % for central IHC versus central FISH. In the primary analysis, the association of HER2 expression by 21-gene assay with trastuzumab benefit was marginally nonsignificant (nonlinear p = 0.057). In hormone receptor-positive patients (local IHC) the association was significant (p = 0.002). The association was nonlinear with the greatest estimated benefit at lower and higher HER2 expression levels. CONCLUSIONS: Concordance among HER2 assessments by central IHC, FISH, and RT-PCR were similar and high. Association of HER2 mRNA expression with trastuzumab benefit as measured by time to distant recurrence was nonsignificant. A consistent benefit of trastuzumab irrespective of mHER2 levels was observed in patients with either IHC-positive or FISH-positive tumors. Trend for benefit was observed also for the small groups of patients with negative results by any or all of the central assays. TRIAL REGISTRATION: Clinicaltrials.gov NCT00005970 . Registered 5 July 2000.


Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/metabolismo , Recidiva Local de Neoplasia/metabolismo , Receptor ErbB-2/metabolismo , Trastuzumab/farmacologia , Adolescente , Adulto , Antineoplásicos/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/mortalidade , Neoplasias da Mama/patologia , Intervalo Livre de Doença , Resistencia a Medicamentos Antineoplásicos , Feminino , Expressão Gênica , Humanos , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/mortalidade , Recidiva Local de Neoplasia/prevenção & controle , Modelos de Riscos Proporcionais , Ensaios Clínicos Controlados Aleatórios como Assunto , Receptor ErbB-2/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Trastuzumab/uso terapêutico , Resultado do Tratamento , Adulto Jovem
7.
Breast Cancer Res Treat ; 152(2): 389-98, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26119102

RESUMO

Validated biomarkers are needed to improve risk assessment and treatment decision-making for women with ductal carcinoma in situ (DCIS) of the breast. The Oncotype DX DCIS Score (DS) was shown to predict the risk of local recurrence (LR) in individuals with low-risk DCIS treated by breast-conserving surgery (BCS) alone. Our objective was to confirm these results in a larger population-based cohort of individuals. We used an established population-based cohort of individuals diagnosed with DCIS treated with BCS alone from 1994 to 2003 with validation of treatment and outcomes. Central pathology assessment excluded cases with invasive cancer, DCIS < 2 mm or positive margins. Cox model was used to determine the relationship between independent covariates, the DS (hazard ratio (HR)/50 Cp units (U)) and LR. Tumor blocks were collected for 828 patients. Final evaluable population includes 718 cases, of whom 571 had negative margins. Median follow-up was 9.6 years. 100 cases developed LR following BCS alone (DCIS, N = 44; invasive, N = 57). In the primary pre-specified analysis, the DS was associated with any LR (DCIS or invasive) in ER+ patients (HR 2.26; P < 0.001) and in all patients regardless of ER status (HR 2.15; P < 0.001). DCIS Score provided independent information on LR risk beyond clinical and pathologic variables including size, age, grade, necrosis, multifocality, and subtype (adjusted HR 1.68; P = 0.02). DCIS was associated with invasive LR (HR 1.78; P = 0.04) and DCIS LR (HR 2.43; P = 0.005). The DCIS Score independently predicts and quantifies individualized recurrence risk in a population of patients with pure DCIS treated by BCS alone.


Assuntos
Neoplasias da Mama/patologia , Neoplasias da Mama/cirurgia , Carcinoma Intraductal não Infiltrante/patologia , Carcinoma Intraductal não Infiltrante/cirurgia , Mastectomia Segmentar , Adulto , Idoso , Neoplasias da Mama/epidemiologia , Carcinoma Intraductal não Infiltrante/epidemiologia , Feminino , Humanos , Estimativa de Kaplan-Meier , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Ontário/epidemiologia , Vigilância da População , Medição de Risco
8.
Oncologist ; 20(4): 344-50, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25795632

RESUMO

BACKGROUND: The Oncotype DX recurrence score (RS) assay has been validated for prediction of 10-year risk of distant recurrence and likelihood of benefit from chemotherapy in patients with estrogen receptor (ER)-positive, HER2-negative early breast cancer. Patients with high RS tumors have substantial benefit, and patients with low RS tumors have minimal if any benefit from chemotherapy. Tumor size is used as a key parameter when selecting patients for neoadjuvant chemotherapy. The aim of this study was to assess the distribution of RS in patients selected for neoadjuvant chemotherapy primarily according to tumor size. PATIENTS AND METHODS: Patients with ER-positive and HER2-negative tumors that were node-negative or had no more than 1 positive node from three trials were included in this study. Oncotype DX was performed at Genomic Health, Inc., blinded to the clinical data. Descriptive statistics were calculated for distribution of RS for all cases. RESULTS: Of 277 patients, 96 met eligibility criteria, and 81 had sufficient material for analysis. Median tumor size was 40 mm (interquartile range [IQR], 30-50 mm). Grade I, II, and III were observed in 13, 49, and 17 cases, respectively. There was a wide distribution of RS with a median of 21.4 (IQR, 16.05-26.75). In total, 23 (28.3%) had high, 28 (34.6%) intermediate, and 30 (37%) low RS results. CONCLUSION: The RS may provide relevant information for neoadjuvant treatment decisions in select patients both in clinical practice and in studies. Inclusion of low RS disease patients in neoadjuvant trials will likely only dilute the ability to look at treatment effects.


Assuntos
Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Perfilação da Expressão Gênica , Recidiva Local de Neoplasia/patologia , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias da Mama/genética , Feminino , Humanos , Pessoa de Meia-Idade , Terapia Neoadjuvante , Recidiva Local de Neoplasia/genética , Estudos Prospectivos , Receptor ErbB-2/metabolismo , Receptores de Estrogênio/metabolismo , Fatores de Risco , Resultado do Tratamento
9.
Cancer Causes Control ; 25(7): 859-68, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24801045

RESUMO

PURPOSE: Pregnancy characteristics have been associated with breast cancer risk, but information is limited on their relationship with breast density. Our objective was to examine the relationship between first pregnancy characteristics and later life breast density, and whether the association is modified by genotype. METHODS: The Marin Women's Study was initiated to examine breast cancer in a high-incidence mammography population (Marin County, CA). Reproductive characteristics and pregnancy information including pregnancy-induced hypertension (PIH) were self-reported at the time of mammography. Forty-seven candidate single nucleotide polymorphisms were obtained from saliva samples; seven were assessed in relation to PIH and percent fibroglandular volume (%FGV). Breast density assessed as %FGV was measured on full-field digital mammograms by the San Francisco Mammography Registry. RESULTS: A multivariable regression model including 2,440 parous women showed that PIH during first pregnancy was associated with a statistically significant decrease in %FGV (b = -0.31, 95 % CI -0.52, -0.11), while each month of breast-feeding after first birth was associated with a statistically significant increase in %FGV (b = 0.01, 95% CI 0.003, 0.02). PIH and breast-feeding associations with %FGV were modified by age at first birth. In a subsample of 1,240 women, there was evidence of modification in the association between PIH and %FGV by specific vascular endothelial growth factor (VEGF) (rs3025039) and insulin growth factor receptor-1 (IGFR1) (rs2016347) gene variants. CONCLUSION: These findings suggest that first pregnancy characteristics may exert an influence on extent of breast density later in life and that this influence may vary depending on inherited IGFR1 and VEGF genotypes.


Assuntos
Neoplasias da Mama/epidemiologia , Mama/patologia , Hipertensão Induzida pela Gravidez , Glândulas Mamárias Humanas/anormalidades , Receptor IGF Tipo 1/genética , Fator A de Crescimento do Endotélio Vascular/genética , Adulto , Fatores Etários , Idoso , Densidade da Mama , Neoplasias da Mama/complicações , Neoplasias da Mama/genética , Estudos Transversais , Feminino , Genótipo , Humanos , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Gravidez
10.
Clin Breast Cancer ; 14(3): 212-220.e1, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24461459

RESUMO

INTRODUCTION: This study was designed to compare the Breast Cancer Risk Assessment Tool (BCRAT; Gail), International Breast Intervention Study (IBIS; Tyrer-Cuzick), and BRCAPRO breast cancer risk assessment models using data from the Marin Women's Study, a cohort of women within Marin County, California, with high rates of breast cancer, nulliparity, and delayed childbirth. Existing models have not been well-validated in these high-risk populations. METHODS: Discrimination was assessed using the area under the receiver operating characteristic curve (AUC) and calibration by estimating the ratio of expected-to-observed (E/O) cases. The models were assessed using data from 12,843 participants, of whom 203 had developed cancer during a 5-year period. All tests of statistical significance were 2-sided. RESULTS: The IBIS model achieved an AUC of 0.65 (95% confidence interval [CI], 0.61-0.68) compared with 0.62 (95% CI, 0.59-0.66) for BCRAT and 0.60 (95% CI, 0.56-0.63) for BRCAPRO. The corresponding estimated E/O ratios for the models were 1.08 (95% CI, 0.95-1.25), 0.81 (95% CI, 0.71-0.93), and 0.59 (95% CI, 0.52-0.68). In women with age at first birth > 30 years, the AUC for the IBIS, BCRAT, and BRCAPRO models was 0.69 (95% CI, 0.62-0.75), 0.63 (95% CI, 0.56-0.70), and 0.62 (95% CI, 0.56-0.68) and the E/O ratio was 1.15 (95% CI, 0.89-1.47), 0.81 (95% CI, 0.63-1.05), and 0.53 (95% CI, 0.41-0.68), respectively. CONCLUSIONS: The IBIS model was well calibrated for the high-risk Marin mammography population and demonstrated the best calibration of the 3 models in nulliparous women. The IBIS model also achieved the greatest overall discrimination and displayed superior discrimination for women with age at first birth > 30 years.


Assuntos
Neoplasias da Mama/epidemiologia , Comportamento Reprodutivo , Adulto , Idoso , Área Sob a Curva , California/epidemiologia , Intervalos de Confiança , Feminino , Humanos , Pessoa de Meia-Idade , Curva ROC , Medição de Risco , Fatores de Risco
11.
Stat Methods Med Res ; 23(3): 293-307, 2014 06.
Artigo em Inglês | MEDLINE | ID: mdl-21908418

RESUMO

There is a rich literature on the role of placebos in experimental design and evaluation of therapeutic agents or interventions. The importance of masking participants, investigators and evaluators to treatment assignment (treatment or placebo) has long been stressed as a key feature of a successful trial design. Nevertheless, there is considerable variability in the technical definition of the placebo effect and the impact of treatment assignments being unmasked. We suggest a formal concept of a 'perception effect' and define unmasking and placebo effects in the context of randomised trials. We employ modern tools from causal inference to derive semi-parametric estimators of such effects. The methods are illustrated on a motivating example from a recent pain trial where the occurrence of treatment-related side effects acts as a proxy for unmasking.


Assuntos
Efeito Placebo , Ensaios Clínicos Controlados Aleatórios como Assunto/métodos , Projetos de Pesquisa , Aminas/uso terapêutico , Ácidos Cicloexanocarboxílicos/uso terapêutico , Feminino , Gabapentina , Humanos , Masculino , Dor/tratamento farmacológico , Placebos , Ácido gama-Aminobutírico/uso terapêutico
12.
Int J Biostat ; 8(2): 7, 2012 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-23324385

RESUMO

A blinded clinical trial design requires masking of patients to prevent measurement of their outcome from being influenced by knowledge of treatment assignment. However, during the course of a trial, some patients may be practically unmasked either due to experiencing treatment related side effects in the treatment arm, or lack of efficacy in the placebo arm. In a recent paper, we introduced concepts of perception, unmasking, and placebo effects for point treatment studies. In this paper, we generalize these concepts to longitudinal studies, and use recent advancements in causal inference and semi-parametric efficient estimation to define and estimate perception and unmasking effects. This allows differentiation of the impact on measured outcomes of 'early' versus 'late' unmasking. In particular, two semi-parametric, substitution methods, one based only on the prediction model (G-computation) and an augmented version of that model for targeted bias-reduction (Targeted Maximum Likelihood Estimation; TMLE), are used for estimation of perception and treatment effects. We motivate our discussion by analyzing data from a recent longitudinal study on the effect of gabapentin on pain among diabetic patients experiencing painful neuropathy.


Assuntos
Método Duplo-Cego , Estudos Longitudinais , Ensaios Clínicos Controlados Aleatórios como Assunto/estatística & dados numéricos , Aminas/efeitos adversos , Aminas/uso terapêutico , Analgésicos/efeitos adversos , Analgésicos/uso terapêutico , Fatores de Confusão Epidemiológicos , Ácidos Cicloexanocarboxílicos/efeitos adversos , Ácidos Cicloexanocarboxílicos/uso terapêutico , Interpretação Estatística de Dados , Neuropatias Diabéticas/tratamento farmacológico , Gabapentina , Humanos , Funções Verossimilhança , Análise de Regressão , Fatores de Tempo , Ácido gama-Aminobutírico/efeitos adversos , Ácido gama-Aminobutírico/uso terapêutico
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