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1.
Pharm Stat ; 20(3): 462-484, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33474798

RESUMO

A standard two-arm randomised controlled trial usually compares an intervention to a control treatment with equal numbers of patients randomised to each treatment arm and only data from within the current trial are used to assess the treatment effect. Historical data are used when designing new trials and have recently been considered for use in the analysis when the required number of patients under a standard trial design cannot be achieved. Incorporating historical control data could lead to more efficient trials, reducing the number of controls required in the current study when the historical and current control data agree. However, when the data are inconsistent, there is potential for biased treatment effect estimates, inflated type I error and reduced power. We introduce two novel approaches for binary data which discount historical data based on the agreement with the current trial controls, an equivalence approach and an approach based on tail area probabilities. An adaptive design is used where the allocation ratio is adapted at the interim analysis, randomising fewer patients to control when there is agreement. The historical data are down-weighted in the analysis using the power prior approach with a fixed power. We compare operating characteristics of the proposed design to historical data methods in the literature: the modified power prior; commensurate prior; and robust mixture prior. The equivalence probability weight approach is intuitive and the operating characteristics can be calculated exactly. Furthermore, the equivalence bounds can be chosen to control the maximum possible inflation in type I error.


Assuntos
Projetos de Pesquisa , Teorema de Bayes , Humanos , Probabilidade , Tamanho da Amostra
2.
Trials ; 21(1): 251, 2020 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-32143729

RESUMO

BACKGROUND: For many disease areas, there are often treatments in different stages of the development process. We consider the design of a two-arm parallel group trial where it is planned to add a new experimental treatment arm during the trial. This could potentially save money, patients, time and resources; however, the addition of a treatment arm creates a multiple comparison problem. Current practice in trials when a new treatment arm has been added is to compare the new treatment only to controls randomised concurrently, and this is the setting we consider here. Furthermore, for standard multi-arm trials, optimal allocation randomises a larger number of patients to the control arm than to each experimental treatment arm. METHODS: In this paper we propose an adaptive design, the aim of which is to adapt the sample size of the trial when the new treatment arm is added to control the family-wise error rate (FWER) in the strong sense, whilst maintaining the marginal power of each treatment-to-control comparison at the level of the original study. We explore optimal allocation for designs where a treatment arm is added with the aim of increasing the overall power of the study, where we define the overall power to be the probability of detecting all treatments that are better than the control. RESULTS AND CONCLUSIONS: An increase in sample size is required to maintain the marginal power for each pairwise comparison when adding a treatment arm if control of the FWER is required at the level of the type I error in the original study. When control of the FWER is required in a single trial which adds an additional experimental treatment arm, but control of the FWER is not required in separate trials, depending on the design characteristics, it may be better to run a separate trial for each experimental treatment, in terms of the number of patients required. An increase in overall power can be achieved when optimal allocation is used once a treatment arm has been added to the trial, rather than continuing with equal allocation to all treatment arms.


Assuntos
Ensaios Clínicos como Assunto/estatística & dados numéricos , Modelos Estatísticos , Projetos de Pesquisa , Interpretação Estatística de Dados , Humanos , Tamanho da Amostra
3.
Sleep Med Rev ; 27: 108-24, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26163056

RESUMO

Obstructive sleep apnoea-hypopnoea (OSAH) causes excessive daytime sleepiness, impairs quality-of-life, and increases cardiovascular disease and road traffic accident risks. Continuous positive airway pressure (CPAP) treatment and mandibular advancement devices (MAD) have been shown to be effective in individual trials but their effectiveness particularly relative to disease severity is unclear. A MEDLINE, Embase and Science Citation Index search updating two systematic reviews to August 2013 identified 77 RCTs in adult OSAH patients comparing: MAD with conservative management (CM); MAD with CPAP; or CPAP with CM. Overall MAD and CPAP significantly improved apnoea-hypopnoea index (AHI) (MAD -9.3/hr (p < 0.001), CPAP -25.4 (p < 0.001)). In direct comparisons mean AHI and Epworth sleepiness scale score were lower (7.0/hr (p < 0.001) and 0.67 (p = 0.093) respectively) for CPAP. There were no CPAP vs. MAD trials in mild OSAH but in comparisons with CM, MAD and CPAP reduced ESS similarly (MAD 2.01 (p < 0.001); CPAP 1.23 (p = 0.012). Both MAD and CPAP are clinically effective in the treatment of OSAH. Although CPAP has a greater treatment effect, MAD is an appropriate treatment for patients who are intolerant of CPAP and may be comparable to CPAP in mild disease.


Assuntos
Pressão Positiva Contínua nas Vias Aéreas/métodos , Avanço Mandibular/instrumentação , Apneia Obstrutiva do Sono/terapia , Doenças Cardiovasculares/etiologia , Humanos , Avanço Mandibular/métodos , Ensaios Clínicos Controlados Aleatórios como Assunto
4.
Health Technol Assess ; 18(67): 1-296, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25359435

RESUMO

BACKGROUND: Obstructive sleep apnoea-hypopnoea (OSAH) causes excessive daytime sleepiness (EDS), impairs quality of life (QoL) and increases cardiovascular disease and road traffic accident risks. Continuous positive airway pressure (CPAP) treatment is clinically effective but undermined by intolerance, and its cost-effectiveness is borderline in milder cases. Mandibular advancement devices (MADs) are another option, but evidence is lacking regarding their clinical effectiveness and cost-effectiveness in milder disease. OBJECTIVES: (1) Conduct a randomised controlled trial (RCT) examining the clinical effectiveness and cost-effectiveness of MADs against no treatment in mild to moderate OSAH. (2) Update systematic reviews and an existing health economic decision model with data from the Trial of Oral Mandibular Advancement Devices for Obstructive sleep apnoea-hypopnoea (TOMADO) and newly published results to better inform long-term clinical effectiveness and cost-effectiveness of MADs and CPAP in mild to moderate OSAH. TOMADO: A crossover RCT comparing clinical effectiveness and cost-effectiveness of three MADs: self-moulded [SleepPro 1™ (SP1); Meditas Ltd, Winchester, UK]; semibespoke [SleepPro 2™ (SP2); Meditas Ltd, Winchester, UK]; and fully bespoke [bespoke MAD (bMAD); NHS Oral-Maxillofacial Laboratory, Addenbrooke's Hospital, Cambridge, UK] against no treatment, in 90 adults with mild to moderate OSAH. All devices improved primary outcome [apnoea-hypopnoea index (AHI)] compared with no treatment: relative risk 0.74 [95% confidence interval (CI) 0.62 to 0.89] for SP1; relative risk 0.67 (95% CI 0.59 to 0.76) for SP2; and relative risk 0.64 (95% CI 0.55 to 0.76) for bMAD (p < 0.001). Differences between MADs were not significant. Sleepiness [as measured by the Epworth Sleepiness Scale (ESS)] was scored 1.51 [95% CI 0.73 to 2.29 (SP1)] to 2.37 [95% CI 1.53 to 3.22 (bMAD)] lower than no treatment (p < 0.001), with SP2 and bMAD significantly better than SP1. All MADs improved disease-specific QoL. Compliance was lower for SP1, which was unpopular at trial exit. At 4 weeks, all devices were cost-effective at £20,000/quality-adjusted life-year (QALY), with SP2 the best value below £39,800/QALY. META-ANALYSIS: A MEDLINE, EMBASE and Science Citation Index search updating two existing systematic reviews (one from November 2006 and the other from June 2008) to August 2013 identified 77 RCTs in adult OSAH patients comparing MAD with conservative management (CM), MADs with CPAP or CPAP with CM. MADs and CPAP significantly improved AHI [MAD -9.3/hour (p < 0.001); CPAP -25.4/hour (p < 0.001)]. Effect difference between CPAP and MADs was 7.0/hour (p < 0.001), favouring CPAP. No trials compared CPAP with MADs in mild OSAH. MAD and CPAP reduced the ESS score similarly [MAD 1.6 (p < 0.001); CPAP 1.6 (p < 0.001)]. LONG-TERM COST-EFFECTIVENESS: An existing model assessed lifetime cost-utility of MAD and CPAP in mild to moderate OSAH, using the revised meta-analysis to update input values. The TOMADO provided utility estimates, mapping ESS score to European Quality of Life-5 Dimensions three-level version for device cost-utility. Using SP2 as the standard device, MADs produced higher mean costs and mean QALYs than CM [incremental cost-effectiveness ratio (ICER) £6687/QALY]. From a willingness to pay (WTP) of £15,367/QALY, CPAP is cost-effective, although the likelihood of MADs (p = 0.48) and CPAP (p = 0.49) being cost-effective is very similar. Both were better than CM, but there was much uncertainty in the choice between CPAP and MAD (at a WTP £20,000/QALY, the probability of being the most cost-effective was 47% for MAD and 52% for CPAP). When SP2 lifespan increased to 18 months, the ICER for CPAP compared with MAD became £44,066. The ICER for SP1 compared with CM was £1552, and for bMAD compared with CM the ICER was £13,836. The ICER for CPAP compared with SP1 was £89,182, but CPAP produced lower mean costs and higher mean QALYs than bMAD. Differential compliance rates for CPAP reduces cost-effectiveness so MADs become less costly and more clinically effective with CPAP compliance 90% of SP2. CONCLUSIONS: Mandibular advancement devices are clinically effective and cost-effective in mild to moderate OSAH. A semi-bespoke MAD is the appropriate first choice in most patients in the short term. Future work should explore whether or not adjustable MADs give additional clinical and cost benefits. Further data on longer-term cardiovascular risk and its risk factors would reduce uncertainty in the health economic model and improve precision of effectiveness estimates. TRIAL REGISTRATION: This trial is registered as ISRCTN02309506. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 18, No. 67. See the NIHR Journals Library website for further project information.


Assuntos
Doenças Cardiovasculares/etiologia , Pressão Positiva Contínua nas Vias Aéreas/instrumentação , Distúrbios do Sono por Sonolência Excessiva/etiologia , Avanço Mandibular/instrumentação , Apneia Obstrutiva do Sono/terapia , Adulto , Idoso , Doenças Cardiovasculares/economia , Comorbidade , Pressão Positiva Contínua nas Vias Aéreas/economia , Pressão Positiva Contínua nas Vias Aéreas/métodos , Análise Custo-Benefício , Estudos Cross-Over , Inglaterra , Feminino , Humanos , Masculino , Avanço Mandibular/economia , Avanço Mandibular/métodos , Pessoa de Meia-Idade , Cooperação do Paciente/estatística & dados numéricos , Anos de Vida Ajustados por Qualidade de Vida , Análise de Regressão , Medição de Risco , Apneia Obstrutiva do Sono/complicações , Apneia Obstrutiva do Sono/economia , Medicina Estatal/economia
5.
Thorax ; 69(10): 938-45, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25035126

RESUMO

RATIONALE: Mandibular advancement devices (MADs) are used to treat obstructive sleep apnoea-hypopnoea syndrome (OSAHS) but evidence is lacking regarding their clinical and cost-effectiveness in less severe disease. OBJECTIVES: To compare clinical- and cost-effectiveness of a range of MADs against no treatment in mild to moderate OSAHS. MEASUREMENTS AND METHODS: This open-label, randomised, controlled, crossover trial was undertaken at a UK sleep centre. Adults with Apnoea-Hypopnoea Index (AHI) 5-<30/h and Epworth Sleepiness Scale (ESS) score ≥9 underwent 6 weeks of treatment with three non-adjustable MADs: self-moulded (SleepPro 1; SP1); semi-bespoke (SleepPro 2; SP2); fully-bespoke MAD (bMAD); and 4 weeks no treatment. Primary outcome was AHI scored by a polysomnographer blinded to treatment. Secondary outcomes included ESS, quality of life, resource use and cost. MAIN RESULTS: 90 patients were randomised and 83 were analysed. All devices reduced AHI compared with no treatment by 26% (95% CI 11% to 38%, p=0.001) for SP1, 33% (95% CI 24% to 41%) for SP2 and 36% (95% CI 24% to 45%, p<0.001) for bMAD. ESS was 1.51 (95% CI 0.73 to 2.29, p<0.001, SP1) to 2.37 (95% CI 1.53 to 3.22, p<0.001, bMAD) lower than no treatment (p<0.001 for all). Compliance was lower for SP1, which was the least preferred treatment at trial exit. All devices were cost-effective compared with no treatment at a £20,000/quality-adjusted life year (QALY) threshold. SP2 was the most cost-effective up to £39,800/QALY. CONCLUSIONS: Non-adjustable MADs achieve clinically important improvements in mild to moderate OSAHS and are cost-effective. Of those trialled, the semi-bespoke MAD is an appropriate first choice. TRIAL REGISTRATION NUMBER: ISRCTN02309506.


Assuntos
Avanço Mandibular/instrumentação , Apneia Obstrutiva do Sono/terapia , Sono/fisiologia , Adulto , Idoso , Análise Custo-Benefício , Estudos Cross-Over , Método Duplo-Cego , Feminino , Seguimentos , Humanos , Masculino , Avanço Mandibular/economia , Pessoa de Meia-Idade , Polissonografia , Qualidade de Vida , Estudos Retrospectivos , Índice de Gravidade de Doença , Apneia Obstrutiva do Sono/diagnóstico , Apneia Obstrutiva do Sono/fisiopatologia , Resultado do Tratamento
6.
Lancet ; 384(9948): 1118-27, 2014 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-24942631

RESUMO

BACKGROUND: Malignant pleural mesothelioma incidence continues to rise, with few available evidence-based therapeutic options. Results of previous non-randomised studies suggested that video-assisted thoracoscopic partial pleurectomy (VAT-PP) might improve symptom control and survival. We aimed to compare efficacy in terms of overall survival, and cost, of VAT-PP and talc pleurodesis in patients with malignant pleural mesothelioma. METHODS: We undertook an open-label, parallel-group, randomised, controlled trial in patients aged 18 years or older with any subtype of confirmed or suspected mesothelioma with pleural effusion, recruited from 12 hospitals in the UK. Eligible patients were randomly assigned (1:1) to either VAT-PP or talc pleurodesis by computer-generated random numbers, stratified by European Organisation for Research and Treatment of Cancer risk category (high vs low). The primary outcome was overall survival at 1 year, analysed by intention to treat (all patients randomly assigned to a treatment group with a final diagnosis of mesothelioma). This trial is registered with ClinicalTrials.gov, number NCT00821860. FINDINGS: Between Oct 24, 2003, and Jan 24, 2012, we randomly assigned 196 patients, of whom 175 (88 assigned to talc pleurodesis, 87 assigned to VAT-PP) had confirmed mesothelioma. Overall survival at 1 year was 52% (95% CI 41-62) in the VAT-PP group and 57% (46-66) in the talc pleurodesis group (hazard ratio 1·04 [95% CI 0·76-1·42]; p=0·81). Surgical complications were significantly more common after VAT-PP than after talc pleurodesis, occurring in 24 (31%) of 78 patients who completed VAT-PP versus ten (14%) of 73 patients who completed talc pleurodesis (p=0·019), as were respiratory complications (19 [24%] vs 11 [15%]; p=0·22) and air-leak beyond 10 days (five [6%] vs one [1%]; p=0·21), although not significantly so. Median hospital stay was longer at 7 days (IQR 5-11) in patients who received VAT-PP compared with 3 days (2-5) for those who received talc pleurodesis (p<0·0001). INTERPRETATION: VAT-PP is not recommended to improve overall survival in patients with pleural effusion due to malignant pleural mesothelioma, and talc pleurodesis might be preferable considering the fewer complications and shorter hospital stay associated with this treatment. FUNDING: BUPA Foundation.


Assuntos
Neoplasias Pulmonares/terapia , Mesotelioma/terapia , Neoplasias Pleurais/terapia , Pleurodese/métodos , Talco/administração & dosagem , Cirurgia Torácica Vídeoassistida/métodos , Idoso , Custos e Análise de Custo , Feminino , Humanos , Estimativa de Kaplan-Meier , Neoplasias Pulmonares/economia , Masculino , Mesotelioma/economia , Mesotelioma Maligno , Neoplasias Pleurais/economia , Neoplasias Pleurais/mortalidade , Pleurodese/economia , Pleurodese/mortalidade , Anos de Vida Ajustados por Qualidade de Vida , Talco/economia , Cirurgia Torácica Vídeoassistida/economia , Cirurgia Torácica Vídeoassistida/mortalidade , Resultado do Tratamento
7.
Chest ; 144(2): 522-530, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23430021

RESUMO

BACKGROUND: The Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR) is a disease-specific assessment tool used for the evaluation and follow-up of patients with pulmonary hypertension (PH). We describe a novel use for this questionnaire in its potential to predict clinical deterioration (CD) in two patient cohorts with subtypes of PH, idiopathic pulmonary arterial hypertension (IPAH), and chronic thromboembolic pulmonary hypertension (CTEPH) during an 8-year period. METHODS: We retrospectively analyzed CAMPHOR scores obtained at baseline and at follow-up visits in patients under the care of our unit over an 8-year period to assess CD and survival, as well as 6-min walk distance (6MWD) and New York Heart Association (NYHA) class. RESULTS: Using Cox regression, we demonstrated a significant predictive effect of CD from total CAMPHOR scores at study enrollment in IPAH and CTEPH (hazard ratios, 1.03 [95% CI, 1.01-1.05] and 1.04 [95% CI, 1.02-1.06] per unit score increase, respectively), as well as from CAMPHOR subscales as independent predictors. This predictive effect is diluted after adjusting for the prognostic effect of 6MWD and NYHA class. Repeated CAMPHOR assessment over time appears not to add predictive value of CD to that obtained at diagnosis, although it still informs physicians of important changes in self-reported symptoms. CONCLUSIONS: When emphasis is placed on the evaluation of patient perceptions, CAMPHOR may represent an alternative method of estimating the likelihood of CD.


Assuntos
Hipertensão Pulmonar/etiologia , Hipertensão Pulmonar/fisiopatologia , Inquéritos e Questionários , Tromboembolia/complicações , Doença Crônica , Progressão da Doença , Hipertensão Pulmonar Primária Familiar , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Retrospectivos , Caminhada/fisiologia
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