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1.
N Engl J Med ; 378(8): 708-718, 2018 02 22.
Artículo en Inglés | MEDLINE | ID: mdl-29364767

RESUMEN

BACKGROUND: Thrombectomy is currently recommended for eligible patients with stroke who are treated within 6 hours after the onset of symptoms. METHODS: We conducted a multicenter, randomized, open-label trial, with blinded outcome assessment, of thrombectomy in patients 6 to 16 hours after they were last known to be well and who had remaining ischemic brain tissue that was not yet infarcted. Patients with proximal middle-cerebral-artery or internal-carotid-artery occlusion, an initial infarct size of less than 70 ml, and a ratio of the volume of ischemic tissue on perfusion imaging to infarct volume of 1.8 or more were randomly assigned to endovascular therapy (thrombectomy) plus standard medical therapy (endovascular-therapy group) or standard medical therapy alone (medical-therapy group). The primary outcome was the ordinal score on the modified Rankin scale (range, 0 to 6, with higher scores indicating greater disability) at day 90. RESULTS: The trial was conducted at 38 U.S. centers and terminated early for efficacy after 182 patients had undergone randomization (92 to the endovascular-therapy group and 90 to the medical-therapy group). Endovascular therapy plus medical therapy, as compared with medical therapy alone, was associated with a favorable shift in the distribution of functional outcomes on the modified Rankin scale at 90 days (odds ratio, 2.77; P<0.001) and a higher percentage of patients who were functionally independent, defined as a score on the modified Rankin scale of 0 to 2 (45% vs. 17%, P<0.001). The 90-day mortality rate was 14% in the endovascular-therapy group and 26% in the medical-therapy group (P=0.05), and there was no significant between-group difference in the frequency of symptomatic intracranial hemorrhage (7% and 4%, respectively; P=0.75) or of serious adverse events (43% and 53%, respectively; P=0.18). CONCLUSIONS: Endovascular thrombectomy for ischemic stroke 6 to 16 hours after a patient was last known to be well plus standard medical therapy resulted in better functional outcomes than standard medical therapy alone among patients with proximal middle-cerebral-artery or internal-carotid-artery occlusion and a region of tissue that was ischemic but not yet infarcted. (Funded by the National Institute of Neurological Disorders and Stroke; DEFUSE 3 ClinicalTrials.gov number, NCT02586415 .).


Asunto(s)
Fibrinolíticos/uso terapéutico , Imagen de Perfusión , Accidente Cerebrovascular/cirugía , Trombectomía , Anciano , Isquemia Encefálica/diagnóstico por imagen , Isquemia Encefálica/cirugía , Angiografía Cerebral , Terapia Combinada , Procedimientos Endovasculares , Femenino , Humanos , Masculino , Persona de Mediana Edad , Método Simple Ciego , Accidente Cerebrovascular/diagnóstico por imagen , Accidente Cerebrovascular/tratamiento farmacológico , Accidente Cerebrovascular/mortalidad , Tiempo de Tratamiento
2.
Stat Med ; 38(4): 613-624, 2019 02 20.
Artículo en Inglés | MEDLINE | ID: mdl-30277591

RESUMEN

After an overview of the Food and Drugs Administration's 2012 draft guidance on enrichment strategies for clinical trials to support drug/biologic approval, we describe subsequent advances in adaptive enrichment designs in this direction. We also provide a concrete application in the enrichment design of the Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution 3 trial comparing a new endovascular treatment with standard of care for ischemic stroke patients.


Asunto(s)
Ensayos Clínicos como Asunto/métodos , Ensayos Clínicos como Asunto/normas , Aprobación de Drogas/métodos , Humanos , Modelos Estadísticos , Tamaño de la Muestra , Estados Unidos , United States Food and Drug Administration/normas
3.
JAMA ; 321(9): 869-879, 2019 03 05.
Artículo en Inglés | MEDLINE | ID: mdl-30835308

RESUMEN

Importance: Coexisting obesity and depression exacerbate morbidity and disability, but effective treatments remain elusive. Objective: To test the hypothesis that an integrated collaborative care intervention would significantly improve both obesity and depression at 12 months compared with usual care. Design, Setting, and Participants: The Research Aimed at Improving Both Mood and Weight (RAINBOW) randomized clinical trial enrolled 409 adults with body mass indices (BMIs) of 30 or greater (≥27 for Asian adults) and 9-item Patient Health Questionnaire (PHQ-9) scores of 10 or greater. Primary care patients at a health system in Northern California were recruited from September 30, 2014, to January 12, 2017; the date of final 12-month follow-up was January 17, 2018. Interventions: All participants randomly assigned to the intervention (n = 204) or the usual care control group (n = 205) received medical care from their personal physicians as usual, received information on routine services for obesity and depression at their clinic, and received wireless physical activity trackers. Intervention participants also received a 12-month intervention that integrated a Diabetes Prevention Program-based behavioral weight loss treatment with problem-solving therapy for depression and, if indicated, antidepressant medications. Main Outcomes and Measures: The co-primary outcome measures were BMI and 20-item Depression Symptom Checklist (SCL-20) scores (range, 0 [best] to 4 [worst]) at 12 months. Results: Among 409 participants randomized (mean age of 51.0 years [SD, 12.1 years]; 70% were women; mean BMI of 36.7 [SD, 6.4]; mean PHQ-9 score of 13.8 [SD, 3.1]; and mean SCL-20 score of 1.5 [SD, 0.5]), 344 (84.1%) completed 12-month follow-up. At 12 months, mean BMI declined from 36.7 (SD, 6.9) to 35.9 (SD, 7.1) among intervention participants compared with a change in mean BMI from 36.6 (SD, 5.8) to 36.6 (SD, 6.0) among usual care participants (between-group mean difference, -0.7 [95% CI, -1.1 to -0.2]; P = .01). Mean SCL-20 score declined from 1.5 (SD, 0.5) to 1.1 (SD, 1.0) at 12 months among intervention participants compared with a change in mean SCL-20 score from 1.5 (SD, 0.6) to 1.4 (SD, 1.3) among usual care participants (between-group mean difference, -0.2 [95% CI, -0.4 to 0]; P = .01). There were 47 adverse events or serious adverse events that involved musculoskeletal injuries (27 in the intervention group and 20 in the usual care group). Conclusions and Relevance: Among adults with obesity and depression, a collaborative care intervention integrating behavioral weight loss treatment, problem-solving therapy, and as-needed antidepressant medications significantly improved weight loss and depressive symptoms at 12 months compared with usual care; however, the effect sizes were modest and of uncertain clinical importance. Trial Registration: ClinicalTrials.gov Identifier: NCT02246413.


Asunto(s)
Antidepresivos/uso terapéutico , Terapia Conductista , Depresión/terapia , Obesidad/terapia , Solución de Problemas , Pérdida de Peso , Actigrafía , Adulto , Análisis de Varianza , Índice de Masa Corporal , Terapia Combinada , Depresión/complicaciones , Depresión/tratamiento farmacológico , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Obesidad/psicología , Método Simple Ciego
4.
Stroke ; 47(12): 2931-2937, 2016 12.
Artículo en Inglés | MEDLINE | ID: mdl-27895297

RESUMEN

BACKGROUND AND PURPOSE: Adaptive trial designs that allow enrichment of the study population through subgroup selection can increase the chance of a positive trial when there is a differential treatment effect among patient subgroups. The goal of this study is to illustrate the potential benefit of adaptive subgroup selection in endovascular stroke studies. METHODS: We simulated the performance of a trial design with adaptive subgroup selection and compared it with that of a traditional design. Outcome data were based on 90-day modified Rankin Scale scores, observed in IMS III (Interventional Management of Stroke III), among patients with a vessel occlusion on baseline computed tomographic angiography (n=382). Patients were categorized based on 2 methods: (1) according to location of the arterial occlusive lesion and onset-to-randomization time and (2) according to onset-to-randomization time alone. The power to demonstrate a treatment benefit was based on 10 000 trial simulations for each design. RESULTS: The treatment effect was relatively homogeneous across categories when patients were categorized based on arterial occlusive lesion and time. Consequently, the adaptive design had similar power (47%) compared with the fixed trial design (45%). There was a differential treatment effect when patients were categorized based on time alone, resulting in greater power with the adaptive design (82%) than with the fixed design (57%). CONCLUSIONS: These simulations, based on real-world patient data, indicate that adaptive subgroup selection has merit in endovascular stroke trials as it substantially increases power when the treatment effect differs among subgroups in a predicted pattern.


Asunto(s)
Ensayos Clínicos como Asunto/estadística & datos numéricos , Procedimientos Endovasculares/estadística & datos numéricos , Evaluación de Resultado en la Atención de Salud/estadística & datos numéricos , Proyectos de Investigación/estadística & datos numéricos , Accidente Cerebrovascular/diagnóstico por imagen , Accidente Cerebrovascular/terapia , Ensayos Clínicos como Asunto/normas , Simulación por Computador , Humanos , Evaluación de Resultado en la Atención de Salud/normas , Proyectos de Investigación/normas , Accidente Cerebrovascular/clasificación
5.
Eur Respir J ; 47(1): 122-32, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26493792

RESUMEN

Rigorous research on the benefit of healthy eating patterns for asthma control is lacking.We randomised 90 adults with objectively confirmed uncontrolled asthma and a low-quality diet (Dietary Approaches to Stop Hypertension (DASH) scores <6 out of 9) to a 6-month DASH behavioural intervention (n=46) or usual-care control (n=44). Intention-to-treat analyses used repeated-measures mixed models.Participants were middle-aged, 67% female and multiethnic. Compared with controls, intervention participants improved on DASH scores (mean change (95% CI) 0.6 (0, 1.1) versus -0.3 (-0.8, 0.2); difference 0.8 (0.2, 1.5)) and the primary outcome, Asthma Control Questionnaire scores (-0.2 (-0.5, 0) versus 0 (-0.3, 0.3); difference -0.2 (-0.5, 0.1)) at 6 months. The mean group differences in changes in Mini Asthma Quality of Life Questionnaire overall and subdomain scores consistently favoured the intervention over the control group: overall 0.4 (95% CI 0, 0.8), symptoms 0.5 (0, 0.9), environment 0.4 (-0.1, 1.0), emotions 0.4 (-0.2, 0.9) and activities 0.3 (0, 0.7). These differences were modest, but potentially clinical significant.The DASH behavioural intervention improved diet quality with promising clinical benefits for better asthma control and functional status among adults with uncontrolled asthma. A full-scale efficacy trial is warranted.


Asunto(s)
Asma/dietoterapia , Terapia Conductista/métodos , Dieta con Restricción de Grasas/métodos , Dieta Hiposódica/métodos , Fibras de la Dieta , Adulto , Antiasmáticos/uso terapéutico , Asma/tratamiento farmacológico , Asma/fisiopatología , Progresión de la Enfermedad , Femenino , Volumen Espiratorio Forzado , Frutas , Humanos , Análisis de Intención de Tratar , Masculino , Persona de Mediana Edad , Proyectos Piloto , Calidad de Vida , Encuestas y Cuestionarios , Resultado del Tratamiento , Verduras , Capacidad Vital
6.
Annu Rev Pharmacol Toxicol ; 52: 101-10, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-21838549

RESUMEN

We review adaptive designs for clinical trials, giving special attention to the control of the Type I error in late-phase confirmatory trials, when the trial planner wishes to adjust the final sample size of the study in response to an unblinded analysis of interim estimates of treatment effects. We point out that there is considerable inefficiency in using the adaptive designs that employ conditional power calculations to reestimate the sample size and that maintain the Type I error by using certain weighted test statistics. Although these adaptive designs have little advantage over familiar group-sequential designs, our review also describes recent developments in adaptive designs that are both flexible and efficient. We also discuss the use of Bayesian designs, when the context of use demands control over operating characteristics (Type I and II errors) and correction of the bias of estimated treatment effects.


Asunto(s)
Sesgo , Ensayos Clínicos como Asunto , Interpretación Estadística de Datos , Proyectos de Investigación , Tamaño de la Muestra , Teorema de Bayes , Humanos , Modelos Estadísticos
7.
Blood ; 121(24): 4955-62, 2013 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-23652802

RESUMEN

Steroid refractory gastrointestinal (GI) acute graft-versus-host disease (aGVHD) is a major cause of mortality in hematopoietic stem cell transplantation (HCT) without immune markers to establish a diagnosis or guide therapy. We found that T-cell receptor ß (TCRß) complementarity-determining region 3 repertoire sequencing reveals patterns that could eventually serve as a disease biomarker of T-cell alloreactivity in aGVHD. We identified T-cell clones in GI biopsies in a heterogeneous group of 15 allogeneic HCT patients with GI aGVHD symptoms. Seven steroid-refractory aGVHD patients showed a more conserved TCRß clonal structure between different biopsy sites in the GI tract than 8 primary therapy-responsive patients. Tracking GI clones identified longitudinally at endoscopy in the blood also revealed an increased clonal expansion in patients with steroid-refractory disease. Immune repertoire sequencing-based methods could enable a novel personalized way to guide diagnosis and therapy in diseases where T-cell activity is a major determinant.


Asunto(s)
Regiones Determinantes de Complementariedad/genética , Enfermedades Gastrointestinales/genética , Enfermedad Injerto contra Huésped/genética , Trasplante de Células Madre Hematopoyéticas , Receptores de Antígenos de Linfocitos T alfa-beta/genética , Adulto , Anciano , Regiones Determinantes de Complementariedad/inmunología , Femenino , Enfermedades Gastrointestinales/diagnóstico , Enfermedades Gastrointestinales/etiología , Enfermedades Gastrointestinales/inmunología , Enfermedades Gastrointestinales/terapia , Enfermedad Injerto contra Huésped/diagnóstico , Enfermedad Injerto contra Huésped/etiología , Enfermedad Injerto contra Huésped/inmunología , Enfermedad Injerto contra Huésped/terapia , Neoplasias Hematológicas/genética , Neoplasias Hematológicas/inmunología , Neoplasias Hematológicas/terapia , Humanos , Masculino , Persona de Mediana Edad , Receptores de Antígenos de Linfocitos T alfa-beta/inmunología , Índice de Severidad de la Enfermedad , Trasplante Homólogo
8.
Stat Med ; 34(9): 1441-53, 2015 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-25581413

RESUMEN

Nonadherence to assigned treatment jeopardizes the power and interpretability of intent-to-treat comparisons from clinical trial data and continues to be an issue for effectiveness studies, despite their pragmatic emphasis. We posit that new approaches to design need to complement developments in methods for causal inference to address nonadherence, in both experimental and practice settings. This paper considers the conventional study design for psychiatric research and other medical contexts, in which subjects are randomized to treatments that are fixed throughout the trial and presents an alternative that converts the fixed treatments into an adaptive intervention that reflects best practice. The key element is the introduction of an adaptive decision point midway into the study to address a patient's reluctance to remain on treatment before completing a full-length trial of medication. The clinical uncertainty about the appropriate adaptation prompts a second randomization at the new decision point to evaluate relevant options. Additionally, the standard 'all-or-none' principal stratification (PS) framework is applied to the first stage of the design to address treatment discontinuation that occurs too early for a midtrial adaptation. Drawing upon the adaptive intervention features, we develop assumptions to identify the PS causal estimand and to introduce restrictions on outcome distributions to simplify expectation-maximization calculations. We evaluate the performance of the PS setup, with particular attention to the role played by a binary covariate. The results emphasize the importance of collecting covariate data for use in design and analysis. We consider the generality of our approach beyond the setting of psychiatric research.


Asunto(s)
Análisis de Intención de Tratar/métodos , Ensayos Clínicos Controlados Aleatorios como Asunto/métodos , Teorema de Bayes , Causalidad , Simulación por Computador , Toma de Decisiones , Humanos , Trastornos Mentales/terapia , Cooperación del Paciente
9.
Biol Blood Marrow Transplant ; 20(6): 837-43, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24607552

RESUMEN

Allogeneic hematopoietic cell transplantation (allo HCT) is the only curative therapy for the myelodysplastic syndromes (MDS) and myeloproliferative neoplasms (MPN), but treatment toxicity has been a barrier to its more widespread use. The nonmyeloablative regimen of total lymphoid irradiation (TLI) and antithymocyte globulin (ATG) permits the establishment of donor hematopoiesis necessary for the graft-versus-malignancy effect and is protective against acute graft-versus-host disease (aGVHD), but it has minimal direct cytotoxicity against myeloid diseases. We explored the use of TLI-ATG conditioning to treat 61 patients with allo HCT for MDS (n = 32), therapy-related myeloid neoplasms (n = 15), MPN (n = 9), and chronic myelomonocytic leukemia (n = 5). The median age of all patients was 63 years (range, 50 to 73). The cumulative incidence of aGVHD grades II to IV was 14% (95% confidence interval [CI], 4% to 23%) and for grades III to IV, 4% (95% CI, 0 to 9%), and it did not differ between patients who received allografts from related or unrelated donors. The cumulative incidence of nonrelapse mortality (NRM) at 100 days, 12 months, and 36 months was 0%, 7%, and 11%. Overall survival and progression-free survival were 41% (95% CI, 29% to 53%) and 35% (95% CI, 23% to 48%), respectively. The safety and tolerability of TLI-ATG, as exemplified by its low NRM, provides a foundation for further risk-adapted or prophylactic interventions to prevent disease progression.


Asunto(s)
Suero Antilinfocítico/administración & dosificación , Trasplante de Células Madre Hematopoyéticas/métodos , Irradiación Linfática/métodos , Síndromes Mielodisplásicos/terapia , Trastornos Mieloproliferativos/terapia , Acondicionamiento Pretrasplante/métodos , Anciano , Análisis de Varianza , Femenino , Humanos , Estimación de Kaplan-Meier , Irradiación Linfática/efectos adversos , Masculino , Persona de Mediana Edad , Quimera por Trasplante , Trasplante Homólogo
11.
Clin Trials ; 11(4): 393-399, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-24784487

RESUMEN

BACKGROUND: In June 2013, a 1-day workshop on Dynamic Treatment Strategies (DTSs) and Sequential Multiple Assignment Randomized Trials (SMARTs) was held at the University of Pennsylvania in Philadelphia, Pennsylvania. These two linked topics have generated a great deal of interest as researchers have recognized the importance of comparing entire strategies for managing chronic disease. A number of articles emerged from that workshop. PURPOSE: The purpose of this survey of the DTS/SMART methodology (which is taken from the introductory talk in the workshop) is to provide the reader the collected articles presented in this volume with sufficient background to appreciate the more detailed discussions in the articles. METHODS: The way that the DTS arises naturally in clinical practice is described, along with its connection to the well-known difficulties of interpreting the analysis by intention-to-treat. The SMART methodology for comparing DTS is described, and the basics of estimation and inference presented. RESULTS: The DTS/SMART methodology can be a flexible and practical way to optimize ongoing clinical decision making, providing evidence (based on randomization) for comparative effectiveness. LIMITATIONS: The DTS/SMART methodology is not a solution for unstandardized study protocols. CONCLUSIONS: The DTS/SMART methodology has growing relevance to comparative effectiveness research and the needs of the learning healthcare system.

12.
Sci Transl Med ; 16(763): eadh3172, 2024 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-39231241

RESUMEN

Mechanistically targeted behavioral interventions are a much-needed strategy for improving outcomes in depression, especially for vulnerable populations with comorbidities such as obesity. Such interventions may change behavior and outcome by changing underlying neural circuit function. However, it is unknown how these circuit-level modifications unfold over intervention and how individual differences in early circuit-level modifications may explain the heterogeneity of treatment effects. We addressed this need within a clinical trial of problem-solving therapy for participants with depression symptoms and comorbid obesity, focusing on the cognitive control circuit as a putative neural mechanism of action. Functional magnetic resonance imaging was applied to measure the cognitive control circuit activity at five time points over 24 months. Compared with participants who received usual care, those receiving problem-solving therapy showed that attenuations in cognitive control circuit activity were associated with enhanced problem-solving ability, which suggests that this circuit plays a key role in the mechanisms of problem-solving therapy. Attenuations in circuit activity were also associated with improved depression symptoms. Changes in cognitive control circuit activity at 2 months better predicted changes in problem-solving ability and depression symptoms at 6, 12, and 24 months, with predictive improvements ranging from 17.8 to 104.0%, exceeding baseline demographic and symptom characteristics. Our findings suggest that targeting the circuit mechanism of action could enhance the prediction of treatment outcomes, warranting future model refinement and improvement to pave the way for its clinical application.


Asunto(s)
Cognición , Depresión , Imagen por Resonancia Magnética , Solución de Problemas , Humanos , Solución de Problemas/fisiología , Depresión/terapia , Depresión/fisiopatología , Cognición/fisiología , Femenino , Masculino , Resultado del Tratamiento , Adulto , Persona de Mediana Edad
13.
N Engl J Med ; 363(17): 1608-20, 2010 Oct 21.
Artículo en Inglés | MEDLINE | ID: mdl-20961244

RESUMEN

BACKGROUND: Warfarin anticoagulation reduces thromboembolic complications in patients with atrial fibrillation or mechanical heart valves, but effective management is complex, and the international normalized ratio (INR) is often outside the target range. As compared with venous plasma testing, point-of-care INR measuring devices allow greater testing frequency and patient involvement and may improve clinical outcomes. METHODS: We randomly assigned 2922 patients who were taking warfarin because of mechanical heart valves or atrial fibrillation and who were competent in the use of point-of-care INR devices to either weekly self-testing at home or monthly high-quality testing in a clinic. The primary end point was the time to a first major event (stroke, major bleeding episode, or death). RESULTS: The patients were followed for 2.0 to 4.75 years, for a total of 8730 patient-years of follow-up. The time to the first primary event was not significantly longer in the self-testing group than in the clinic-testing group (hazard ratio, 0.88; 95% confidence interval, 0.75 to 1.04; P=0.14). The two groups had similar rates of clinical outcomes except that the self-testing group reported more minor bleeding episodes. Over the entire follow-up period, the self-testing group had a small but significant improvement in the percentage of time during which the INR was within the target range (absolute difference between groups, 3.8 percentage points; P<0.001). At 2 years of follow-up, the self-testing group also had a small but significant improvement in patient satisfaction with anticoagulation therapy (P=0.002) and quality of life (P<0.001). CONCLUSIONS: As compared with monthly high-quality clinic testing, weekly self-testing did not delay the time to a first stroke, major bleeding episode, or death to the extent suggested by prior studies. These results do not support the superiority of self-testing over clinic testing in reducing the risk of stroke, major bleeding episode, and death among patients taking warfarin therapy. (Funded by the Department of Veterans Affairs Cooperative Studies Program; ClinicalTrials.gov number, NCT00032591.).


Asunto(s)
Anticoagulantes/uso terapéutico , Monitoreo de Drogas/métodos , Relación Normalizada Internacional , Autocuidado , Warfarina/uso terapéutico , Anciano , Anticoagulantes/efectos adversos , Fibrilación Atrial/tratamiento farmacológico , Femenino , Estudios de Seguimiento , Prótesis Valvulares Cardíacas , Hemorragia/epidemiología , Hemorragia/prevención & control , Humanos , Estimación de Kaplan-Meier , Masculino , Persona de Mediana Edad , Mortalidad , Infarto del Miocardio/epidemiología , Estudios Prospectivos , Accidente Cerebrovascular/epidemiología , Accidente Cerebrovascular/prevención & control , Trombosis/prevención & control , Warfarina/efectos adversos
14.
Biostatistics ; 13(1): 142-52, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21765180

RESUMEN

Clinical demand for individualized "adaptive" treatment policies in diverse fields has spawned development of clinical trial methodology for their experimental evaluation via multistage designs, building upon methods intended for the analysis of naturalistically observed strategies. Because often there is no need to parametrically smooth multistage trial data (in contrast to observational data for adaptive strategies), it is possible to establish direct connections among different methodological approaches. We show by algebraic proof that the maximum likelihood (ML) and optimal semiparametric (SP) estimators of the population mean of the outcome of a treatment policy and its standard error are equal under certain experimental conditions. This result is used to develop a unified and efficient approach to design and inference for multistage trials of policies that adapt treatment according to discrete responses. We derive a sample size formula expressed in terms of a parametric version of the optimal SP population variance. Nonparametric (sample-based) ML estimation performed well in simulation studies, in terms of achieved power, for scenarios most likely to occur in real studies, even though sample sizes were based on the parametric formula. ML outperformed the SP estimator; differences in achieved power predominately reflected differences in their estimates of the population mean (rather than estimated standard errors). Neither methodology could mitigate the potential for overestimated sample sizes when strong nonlinearity was purposely simulated for certain discrete outcomes; however, such departures from linearity may not be an issue for many clinical contexts that make evaluation of competitive treatment policies meaningful.


Asunto(s)
Medicina de Precisión/métodos , Ensayos Clínicos Controlados Aleatorios como Asunto/estadística & datos numéricos , Antidepresivos/uso terapéutico , Bioestadística , Depresión/tratamiento farmacológico , Humanos , Funciones de Verosimilitud , Dinámicas no Lineales , Medicina de Precisión/estadística & datos numéricos , Tamaño de la Muestra
15.
Biol Psychiatry Glob Open Sci ; 3(3): 430-442, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37519462

RESUMEN

Background: Integrated treatments for comorbid depression (often with anxiety) and obesity are lacking; mechanisms are poorly investigated. Methods: In a mechanistic pilot trial, adults with body mass index ≥30 and Patient Health Questionnaire-9 scores ≥10 were randomized to usual care (n = 35) or an integrated behavioral intervention (n = 71). Changes at 6 months in body mass index and Depression Symptom Checklist-20 scores were co-primary outcomes, and Generalized Anxiety Disorder Scale-7 score was a secondary outcome. Changes at 2 months in the activation and functional connectivity of regions of interest in the negative affect circuit were primary neural targets, and secondary targets were in the cognitive control, default mode, and positive affect circuits. Results: Participants were 47.0 years (SD = 11.9 years), 76% women, 55% Black, and 20% Latino. Depression Symptom Checklist-20 (between-group difference, -0.3 [95% CI: -0.6 to -0.1]) and Generalized Anxiety Disorder Scale-7 (-2.9 [-4.7 to -1.1]) scores, but not body mass index, decreased significantly at 6 months in the intervention versus usual care groups. Only Generalized Anxiety Disorder Scale-7 score changes at 6 months significantly correlated with neural target changes at 2 months in the negative affect (anterior insula, subgenual/pregenual anterior cingulate cortex, amygdala) and cognitive control circuits (dorsal lateral prefrontal cortex, dorsal anterior cingulate cortex). Effects were medium to large (0.41-1.18 SDs). Neural target changes at 2 months in the cognitive control circuit only differed by treatment group. Effects were medium (0.58-0.79 SDs). Conclusions: Compared with usual care, the study intervention led to significantly improved depression but not weight loss, and the results on neural targets were null for both outcomes. The significant intervention effect on anxiety might be mediated through changes in the cognitive control circuit, but this warrants replication.

16.
Stat Med ; 31(18): 1944-60, 2012 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-22422502

RESUMEN

Although traditional phase II cancer trials are usually single arm, with tumor response as endpoint, and phase III trials are randomized and incorporate interim analyses with progression-free survival or other failure time as endpoint, this paper proposes a new approach that seamlessly expands a randomized phase II study of response rate into a randomized phase III study of time to failure. This approach is based on advances in group sequential designs and joint modeling of the response rate and time to event. The joint modeling is reflected in the primary and secondary objectives of the trial, and the sequential design allows the trial to adapt to increase in information on response and survival patterns during the course of the trial and to stop early either for conclusive evidence on efficacy of the experimental treatment or for the futility in continuing the trial to demonstrate it, on the basis of the data collected so far.


Asunto(s)
Ensayos Clínicos Fase II como Asunto/métodos , Ensayos Clínicos Fase III como Asunto/métodos , Antineoplásicos/uso terapéutico , Neoplasias Óseas/secundario , Simulación por Computador , Supervivencia sin Enfermedad , Humanos , Masculino , Modelos Estadísticos , Neoplasias Hormono-Dependientes/tratamiento farmacológico , Neoplasias Hormono-Dependientes/patología , Neoplasias de la Próstata/tratamiento farmacológico , Neoplasias de la Próstata/patología , Proyectos de Investigación
17.
Clin Trials ; 9(2): 141-54, 2012 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-22397801

RESUMEN

BACKGROUND: Advances in molecular therapeutics in the past decade have opened up new possibilities for treating cancer patients with personalized therapies, using biomarkers to determine which treatments are most likely to benefit them, but there are difficulties and unresolved issues in the development and validation of biomarker-based personalized therapies. We develop a new clinical trial design to address some of these issues. The goal is to capture the strengths of the frequentist and Bayesian approaches to address this problem in the recent literature and to circumvent their limitations. METHODS: We use generalized likelihood ratio tests of the intersection null and enriched strategy null hypotheses to derive a novel clinical trial design for the problem of advancing promising biomarker-guided strategies toward eventual validation. We also investigate the usefulness of adaptive randomization (AR) and futility stopping proposed in the recent literature. RESULTS: Simulation studies demonstrate the advantages of testing both the narrowly focused enriched strategy null hypothesis related to validating a proposed strategy and the intersection null hypothesis that can accommodate to a potentially successful strategy. AR and early termination of ineffective treatments offer increased probability of receiving the preferred treatment and better response rates for patients in the trial, at the expense of more complicated inference under small-to-moderate total sample sizes and some reduction in power. LIMITATIONS: The binary response used in the development phase may not be a reliable indicator of treatment benefit on long-term clinical outcomes. In the proposed design, the biomarker-guided strategy (BGS) is not compared to 'standard of care', such as physician's choice that may be informed by patient characteristics. Therefore, a positive result does not imply superiority of the BGS to 'standard of care'. The proposed design and tests are valid asymptotically. Simulations are used to examine small-to-moderate sample properties. CONCLUSION: Innovative clinical trial designs are needed to address the difficulties and issues in the development and validation of biomarker-based personalized therapies. The article shows the advantages of using likelihood inference and interim analysis to meet the challenges in the sample size needed and in the constantly evolving biomarker landscape and genomic and proteomic technologies.


Asunto(s)
Biomarcadores , Ensayos Clínicos como Asunto/métodos , Medicina de Precisión , Proyectos de Investigación , Teorema de Bayes , Resistencia a Medicamentos , Terminación Anticipada de los Ensayos Clínicos , Femenino , Humanos , Modelos Estadísticos , Neoplasias Ováricas/tratamiento farmacológico , Platino (Metal)/uso terapéutico , Ensayos Clínicos Controlados Aleatorios como Asunto , Tamaño de la Muestra
18.
J Urol ; 185(2): 483-7, 2011 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-21167519

RESUMEN

PURPOSE: The prostate cancer risk calculator from the Prostate Cancer Prevention Trial estimates the risk of positive biopsy and 1 containing high grade disease (Gleason score 7 or greater) based on prostate specific antigen, digital rectal examination, family history, race and prior negative biopsy. Since data used to create the calculator came from an unreferred population that underwent mainly sextant biopsy, to our knowledge its usefulness in the contemporary urology practice is unknown. MATERIALS AND METHODS: We performed the same multivariate logistic regression used to derive the prostate cancer risk calculator in a cohort of men from the Stanford Prostate Needle Biopsy Database who underwent initial prostate needle biopsy using an extended 12-core scheme. RESULTS: Our predictions of overall prostate cancer risk did not differ significantly from those of the calculator. Prostate specific antigen, abnormal digital rectal examination and family history were independent risk factors. However, our model predicted a much greater risk of high grade disease than the prostate cancer risk calculator. Prostate specific antigen, abnormal digital rectal examination and age were independent risk factors for high grade disease. CONCLUSIONS: The difference between our estimated risk of high grade prostate cancer and that of the prostate cancer risk calculator can be potentially explained by 1) differences between the cohorts (referred vs unreferred) or 2) the difference in grading, ie grading accuracy due to the difference in biopsy schemes or to temporally related grade shifts. Caution should be used when applying the prostate cancer risk calculator to counsel patients referred for suspicion of prostate cancer since it underestimates the risk of high grade disease.


Asunto(s)
Tamizaje Masivo , Antígeno Prostático Específico/sangre , Neoplasias de la Próstata/diagnóstico , Neoplasias de la Próstata/prevención & control , Derivación y Consulta/estadística & datos numéricos , Medición de Riesgo , Adulto , Distribución por Edad , Anciano , Biomarcadores de Tumor/sangre , Biopsia con Aguja , California , Estudios de Cohortes , Tacto Rectal/métodos , Humanos , Incidencia , Modelos Logísticos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Estadificación de Neoplasias , Nomogramas , Oportunidad Relativa , Valor Predictivo de las Pruebas , Pronóstico , Modelos de Riesgos Proporcionales , Neoplasias de la Próstata/epidemiología
19.
Blood ; 114(5): 1099-109, 2009 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-19423725

RESUMEN

A hematopoietic cell transplantation regimen was adapted from a preclinical model that used reduced-intensity conditioning (RIC) and protected against graft-versus-host disease (GVHD) by skewing residual host T-cell subsets to favor regulatory natural killer T cells. One hundred eleven patients with lymphoid (64) and myeloid (47) malignancies received RIC using total lymphoid irradiation (TLI) and antithymocyte globulin (ATG) followed by the infusion of granulocyte colony-stimulating factor-mobilized grafts. Included were 34 patients at least 60 years of age, 32 patients at high risk of lymphoma relapse after disease recurrence following prior autologous transplantation, and 51 patients at high risk of developing GVHD due to lack of a fully human leukocyte antigen (HLA)-matched related donor. Durable chimerism was achieved in 97% of patients. Cumulative probabilities of acute GVHD (grades II-IV) were 2 and 10% of patients receiving related and unrelated donor grafts. Nonrelapse mortality (NRM) at 1 year was less than 4%. Cumulative incidence of chronic GVHD was 27%. The 36-month probability of overall and event-free survival was 60% and 40%, respectively. Disease status at start of conditioning and the level of chimerism achieved after transplantation significantly impacted clinical outcome. The high incidence of sustained remission among patients with active disease at time of transplantation suggests retained graft-versus-tumor reactions. Active trial registration currently at clinicaltrials.gov under IDs of NCT00185640 and NCT00186615.


Asunto(s)
Suero Antilinfocítico/administración & dosificación , Neoplasias Hematológicas/cirugía , Trasplante de Células Madre Hematopoyéticas , Donadores Vivos , Irradiación Linfática , Linfocitos T/inmunología , Acondicionamiento Pretrasplante/métodos , Adulto , Anciano , Antiinfecciosos/uso terapéutico , Ciclosporina/uso terapéutico , Supervivencia sin Enfermedad , Familia , Femenino , Enfermedad Injerto contra Huésped/epidemiología , Enfermedad Injerto contra Huésped/prevención & control , Factor Estimulante de Colonias de Granulocitos/uso terapéutico , Neoplasias Hematológicas/mortalidad , Humanos , Inmunosupresores/uso terapéutico , Masculino , Persona de Mediana Edad , Ácido Micofenólico/análogos & derivados , Ácido Micofenólico/uso terapéutico , Premedicación , Riesgo , Trasplante Homólogo , Resultado del Tratamiento
20.
Clin Trials ; 8(2): 183-95, 2011 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-21478329

RESUMEN

BACKGROUND: Clinical trials are widely considered the gold standard in comparative effectiveness research (CER) but the high cost and complexity of traditional trials and concerns about generalizability to broad patient populations and general clinical practice limit their appeal. Unsuccessful implementation of CER results limits the value of even the highest quality trials. Planning for a trial comparing two standard strategies of insulin administration for hospitalized patients led us to develop a new method for a clinical trial designed to be embedded directly into the clinical care setting thereby lowering the cost, increasing the pragmatic nature of the overall trial, strengthening implementation, and creating an integrated environment of research-based care. PURPOSE: We describe a novel randomized clinical trial that uses the informatics and statistics infrastructure of the Veterans Affairs Healthcare System (VA) to illustrate one key component (called the point-of-care clinical trial - POC-CT) of a 'learning healthcare system,' and settles a clinical question of interest to the VA. METHODS: This study is an open-label, randomized trial comparing sliding scale regular insulin to a weight-based regimen for control of hyperglycemia, using the primary outcome length of stay, in non-ICU inpatients within the northeast region of the VA. All non-ICU patients who require in-hospital insulin therapy are eligible for the trial, and the VA's automated systems will be used to assess eligibility and present the possibility of randomization to the clinician at the point of care. Clinicians will indicate their approval for informed consent to be obtained by study staff. Adaptive randomization will assign up to 3000 patients, preferentially to the currently 'winning' strategy, and all care will proceed according to usual practices. Based on a Bayesian stopping rule, the study has acceptable frequentist operating characteristics (Type I error 6%, power 86%) against a 12% reduction of median length of stay from 5 to 4.4 days. The adaptive stopping rule promotes implementation of a successful treatment strategy. LIMITATIONS: Despite clinical equipoise, individual healthcare providers may have strong treatment preferences that jeopardize the success and implementation of the trial design, leading to low rates of randomization. Unblinded treatment assignment may bias results. In addition, generalization of clinical results to other healthcare systems may be limited by differences in patient population. Generalizability of the POC-CT method depends on the level of informatics and statistics infrastructure available to a healthcare system. CONCLUSIONS: The methods proposed will demonstrate outcome-based evaluation of control of hyperglycemia in hospitalized veterans. By institutionalizing a process of statistically sound and efficient learning, and by integrating that learning with automatic implementation of best practice, the participating VA Healthcare Systems will accelerate improvements in the effectiveness of care.


Asunto(s)
Hiperglucemia/tratamiento farmacológico , Insulina/administración & dosificación , Tiempo de Internación , Sistemas de Entrada de Órdenes Médicas , Sistemas de Atención de Punto , Ensayos Clínicos Controlados Aleatorios como Asunto/métodos , Peso Corporal , Investigación sobre la Eficacia Comparativa , Relación Dosis-Respuesta a Droga , Registros Electrónicos de Salud , Humanos , Insulina/uso terapéutico , Proyectos de Investigación
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