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Ferreira MLV, Castro A, de Oliveira Nunes SG, Dos Santos MVMA, Cavaglieri CR, Tanaka H, Chacon-Mikahil MPT. Hypotensive effects of exercise training: are postmenopausal women with hypertension non-responders or responders? Hypertens Res 2024:10.1038/s41440-024-01721-8. [PMID: 38778171 DOI: 10.1038/s41440-024-01721-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 03/28/2024] [Accepted: 04/17/2024] [Indexed: 05/25/2024]
Abstract
We tested the hypothesis that increasing the exercise dose or changing the exercise mode would augment hypotensive effects when traditional aerobic exercise training failed to produce it in postmenopausal women. Sixty-five postmenopausal women with essential hypertension were randomly allocated into the continuous aerobic training (CAT) and non-exercising control (CON) groups. CAT group cycled at moderate intensity 3 times a week for 12 weeks. Individuals who failed to decrease systolic blood pressure (BP) were classified as non-responders (n = 34) and performed an additional 12 weeks of exercise training with either increasing the exercise dose or changing the exercise mode. The 3 follow-up groups were continuous aerobic training 3 times a week, continuous aerobic training 4 times a week, and high-intensity interval training. After the first 12 weeks of exercise training, systolic BP decreased by 1.5 mmHg (NS) with a wide range of inter-individual responses (-23 to 23 mmHg). Sixty-seven percent of women who were initially classified as non-responders participated in the second training period. Sixty percent of women who participated in continuous exercise training 3 or 4 times a week at greater exercise intensities reduced systolic BP. All (100%) of the women who performed high-intensity interval training experienced significant reductions in systolic BP. Traditional aerobic exercise was not sufficient to decrease BP significantly in the majority of postmenopausal women. However, those women who were not sensitive to recommended exercise may reduce BP if they were exposed to continuous aerobic exercise at higher intensities and/or volumes or a different mode of exercise.
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Affiliation(s)
- Marina Lívia Venturini Ferreira
- Laboratory of Exercise Physiology, School of Physical Education, University of Campinas, Campinas, São Paulo, Brazil.
- Cardiovascular Aging Research Laboratory, Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, TX, USA.
| | - Alex Castro
- Laboratory of Exercise Physiology, School of Physical Education, University of Campinas, Campinas, São Paulo, Brazil
- Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | | | | | - Cláudia Regina Cavaglieri
- Laboratory of Exercise Physiology, School of Physical Education, University of Campinas, Campinas, São Paulo, Brazil
| | - Hirofumi Tanaka
- Cardiovascular Aging Research Laboratory, Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, TX, USA
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2
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Luh WM, Guo JH. Unequal allocation of sample/event sizes with considerations of sampling cost for testing equality, non-inferiority/superiority, and equivalence of two Poisson rates. Int J Biostat 2024; 20:143-156. [PMID: 36583245 DOI: 10.1515/ijb-2022-0039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Accepted: 12/09/2022] [Indexed: 12/31/2022]
Abstract
For non-inferiority/superiority and equivalence tests of two Poisson rates, the determination of the required number of sample sizes has been studied but the studies for the number of events to be observed are very limited. To fill the gap, the present study first is aimed toward determining the number of events to be observed for testing non-inferiority/superiority and equivalence of two Poisson rates, respectively. Also, considering the cost for each event, the second purpose is to apply an exhaustive search to find the unequal but optimal allocation of events for each group such that the budget is minimal for a user-specified power level, or the statistical power is maximal for a user-specified budget. Four R Shiny apps were developed to obtain the number of events needed for each group. A simulation study showed the proposed approach to be valid in terms of Type I error and statistical power. A comparison of the proposed approach with extant methods from various disciplines was performed, and an illustrative example of comparing the adverse reactions to the COVID-19 vaccines was demonstrated. By applying the proposed approach, researchers also can estimate the most economical number of subjects or time intervals after determining the number of events.
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Affiliation(s)
- Wei-Ming Luh
- National Cheng Kung University, Tainan, 70101, Taiwan
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3
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Bertoni S, Andreola C, Mascheretti S, Franceschini S, Ruffino M, Trezzi V, Molteni M, Sali ME, Salandi A, Gaggi O, Palazzi C, Gori S, Facoetti A. Action video games normalise the phonemic awareness in pre-readers at risk for developmental dyslexia. NPJ SCIENCE OF LEARNING 2024; 9:25. [PMID: 38514689 PMCID: PMC10957868 DOI: 10.1038/s41539-024-00230-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Accepted: 02/26/2024] [Indexed: 03/23/2024]
Abstract
Action video-games (AVGs) could improve reading efficiency, enhancing not only visual attention but also phonological processing. Here we tested the AVG effects upon three consolidated language-based predictors of reading development in a sample of 79 pre-readers at-risk and 41 non-at-risk for developmental dyslexia. At-risk children were impaired in either phonemic awareness (i.e., phoneme discrimination task), phonological working memory (i.e., pseudoword repetition task) or rapid automatized naming (i.e., RAN of colours task). At-risk children were assigned to different groups by using an unequal allocation randomization: (1) AVG (n = 43), (2) Serious Non-Action Video Game (n = 11), (3) treatment-as-usual (i.e., speech therapy, n = 11), and (4) waiting list (n = 14). Pre- and post-training comparisons show that only phonemic awareness has a significantly higher improvement in the AVG group compared to the waiting list, the non-AVG, and the treatment-as-usual groups, as well as the combined active groups (n = 22). This cross-modal plastic change: (i) leads to a recovery in phonemic awareness when compared to the not-at-risk pre-readers; (ii) is present in more than 80% of AVG at-risk pre-readers, and; (iii) is maintained at a 6-months follow-up. The present findings indicate that this specific multisensory attentional training positively affects how phonemic awareness develops in pre-readers at risk for developmental dyslexia, paving the way for innovative prevention programs.
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Affiliation(s)
- Sara Bertoni
- Università di Bergamo, Department of Human and Social Sciences, Bergamo, Italy.
- Università di Padova, Developmental Cognitive Neuroscience Lab, Department of General Psychology, Padova, Italy.
| | - Chiara Andreola
- Université Paris Cité, Laboratoire de Psychologie de Développement et de l'Éducation de l'Enfant (LaPsyDÉ), UMR CNRS 8240, Paris, France
| | - Sara Mascheretti
- Università di Pavia, Department of Brain and Behavioral Sciences, Pavia, Italy
- Scientific Institute, IRCCS E. Medea, Bosisio Parini, Child Psychopathology Unit, Lecco, Italy
| | | | - Milena Ruffino
- ASST Valle Olona, Neuropsychiatric Unit, Saronno, Varese, Italy
| | - Vittoria Trezzi
- Scientific Institute, IRCCS E. Medea, Bosisio Parini, Child Psychopathology Unit, Lecco, Italy
| | - Massimo Molteni
- Scientific Institute, IRCCS E. Medea, Bosisio Parini, Child Psychopathology Unit, Lecco, Italy
| | - Maria Enrica Sali
- Scientific Institute, IRCCS E. Medea, Bosisio Parini, Child Psychopathology Unit, Lecco, Italy
| | - Antonio Salandi
- Scientific Institute, IRCCS E. Medea, Bosisio Parini, Child Psychopathology Unit, Lecco, Italy
| | | | | | - Simone Gori
- Università di Bergamo, Department of Human and Social Sciences, Bergamo, Italy
| | - Andrea Facoetti
- Università di Padova, Developmental Cognitive Neuroscience Lab, Department of General Psychology, Padova, Italy.
- Sigmund Freud University, Milano, Italy.
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Sverdlov O, Ryeznik Y, Anisimov V, Kuznetsova OM, Knight R, Carter K, Drescher S, Zhao W. Selecting a randomization method for a multi-center clinical trial with stochastic recruitment considerations. BMC Med Res Methodol 2024; 24:52. [PMID: 38418968 PMCID: PMC10900599 DOI: 10.1186/s12874-023-02131-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Accepted: 12/19/2023] [Indexed: 03/02/2024] Open
Abstract
BACKGROUND The design of a multi-center randomized controlled trial (RCT) involves multiple considerations, such as the choice of the sample size, the number of centers and their geographic location, the strategy for recruitment of study participants, amongst others. There are plenty of methods to sequentially randomize patients in a multi-center RCT, with or without considering stratification factors. The goal of this paper is to perform a systematic assessment of such randomization methods for a multi-center 1:1 RCT assuming a competitive policy for the patient recruitment process. METHODS We considered a Poisson-gamma model for the patient recruitment process with a uniform distribution of center activation times. We investigated 16 randomization methods (4 unstratified, 4 region-stratified, 4 center-stratified, 3 dynamic balancing randomization (DBR), and a complete randomization design) to sequentially randomize n = 500 patients. Statistical properties of the recruitment process and the randomization procedures were assessed using Monte Carlo simulations. The operating characteristics included time to complete recruitment, number of centers that recruited a given number of patients, several measures of treatment imbalance and estimation efficiency under a linear model for the response, the expected proportions of correct guesses under two different guessing strategies, and the expected proportion of deterministic assignments in the allocation sequence. RESULTS Maximum tolerated imbalance (MTI) randomization methods such as big stick design, Ehrenfest urn design, and block urn design result in a better balance-randomness tradeoff than the conventional permuted block design (PBD) with or without stratification. Unstratified randomization, region-stratified randomization, and center-stratified randomization provide control of imbalance at a chosen level (trial, region, or center) but may fail to achieve balance at the other two levels. By contrast, DBR does a very good job controlling imbalance at all 3 levels while maintaining the randomized nature of treatment allocation. Adding more centers into the study helps accelerate the recruitment process but at the expense of increasing the number of centers that recruit very few (or no) patients-which may increase center-level imbalances for center-stratified and DBR procedures. Increasing the block size or the MTI threshold(s) may help obtain designs with improved randomness-balance tradeoff. CONCLUSIONS The choice of a randomization method is an important component of planning a multi-center RCT. Dynamic balancing randomization with carefully chosen MTI thresholds could be a very good strategy for trials with the competitive policy for patient recruitment.
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Affiliation(s)
| | - Yevgen Ryeznik
- Department of Pharmacy, Uppsala University, Uppsala, Sweden
| | | | | | - Ruth Knight
- Liverpool Clinical Trials Centre, University of Liverpool, Merseyside, Liverpool, UK
| | - Kerstine Carter
- Boehringer-Ingelheim Pharmaceuticals Inc, Ridgefield, CT, USA
| | - Sonja Drescher
- Boehringer-Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
| | - Wenle Zhao
- Medical University of South Carolina, Charleston, SC, USA
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Moerbeek M. Optimal allocation of clusters in stepped wedge designs with a decaying correlation structure. PLoS One 2023; 18:e0289275. [PMID: 37585398 PMCID: PMC10431648 DOI: 10.1371/journal.pone.0289275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 07/15/2023] [Indexed: 08/18/2023] Open
Abstract
The cluster randomized stepped wedge design is a multi-period uni-directional switch design in which all clusters start in the control condition and at the beginning of each new period a random sample of clusters crosses over to the intervention condition. Such designs often use uniform allocation, with an equal number of clusters at each treatment switch. However, the uniform allocation is not necessarily the most efficient. This study derives the optimal allocation of clusters to treatment sequences in the cluster randomized stepped wedge design, for both cohort and cross-sectional designs. The correlation structure is exponential decay, meaning the correlation decreases with the time lag between two measurements. The optimal allocation is shown to depend on the intraclass correlation coefficient, the number of subjects per cluster-period and the cluster and (in the case of a cohort design) individual autocorrelation coefficients. For small to medium values of these autocorrelations those sequences that have their treatment switch earlier or later in the study are allocated a larger proportion of clusters than those clusters that have their treatment switch halfway the study. When the autocorrelation coefficients increase, the clusters become more equally distributed across the treatment sequences. For the cohort design, the optimal allocation is almost equal to the uniform allocation when both autocorrelations approach the value 1. For almost all scenarios that were studied, the efficiency of the uniform allocation is 0.8 or higher. R code to derive the optimal allocation is available online.
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Affiliation(s)
- Mirjam Moerbeek
- Department of Methodology and Statistics, Utrecht University, Utrecht, The Netherlands
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6
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Kanchanathepsak T, Pukrittayakamee NC, Woratanarat P, Tawonsawatruk T, Angsanuntsukh C. Limb occlusion pressure versus standard tourniquet inflation pressure in minor hand surgery: a randomized controlled trial. J Orthop Surg Res 2023; 18:539. [PMID: 37507745 PMCID: PMC10386602 DOI: 10.1186/s13018-023-04000-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 07/11/2023] [Indexed: 07/30/2023] Open
Abstract
BACKGROUND In minor hand surgery, tourniquet is typically inflated to 250 mmHg. The pressure may be too high and cause unnecessary adverse effects. Limb occlusion pressure plus safety margin or recommended tourniquet pressure (RTP), has been reported as optimal pressure to provide bloodless field in limb surgeries. This study aimed to compare the RTP with the standard tourniquet pressure of 250 mmHg in minor hand surgery. METHODS A double-blinded randomized control trial was conducted from July to December 2019 and June 2020 to May 2021. Patients were randomly assigned into two groups: RTP and 250 mmHg with 3:1 ratio allocation. The outcomes were measurement of cuff pressure reduction, time to develop of tourniquet pain and discomfort, pain score, discomfort score, motionless and bloodless of operative field determined by the surgeon's satisfaction. RESULTS A total of 112 patients were included, 84 were in RTP and 28 were in 250 mmHg group. Mean of tourniquet pressure was significantly lower in the RTP group (228.3 ± 17.2 mmHg) (P < 0.001). Even though, time to develop pain was not significantly different, the RTP group reported significantly less pain and discomfort, according to the pain score (P = 0.02) and discomfort score (P = 0.017). The RTP group provided better motionless field, while both groups equally created a bloodless field. CONCLUSION The RTP significantly reduced tourniquet related pain and discomfort during minor hand surgeries. It provided better motionless operative field and adequate bloodless field. Therefore, the RTP should be considered as optimal tourniquet pressure for minor hand surgeries. TRIAL REGISTRATION TCTR20210519001 (retrospectively registered). LEVEL OF EVIDENCE I.
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Affiliation(s)
- Thepparat Kanchanathepsak
- Department of Orthopaedics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, 270 Rama VI Road, Ratchathewi, Bangkok, 10400, Thailand
| | - Natsuda Chua Pukrittayakamee
- Department of Orthopaedics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, 270 Rama VI Road, Ratchathewi, Bangkok, 10400, Thailand
| | - Patarawan Woratanarat
- Department of Orthopaedics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, 270 Rama VI Road, Ratchathewi, Bangkok, 10400, Thailand
| | - Tulyapruek Tawonsawatruk
- Department of Orthopaedics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, 270 Rama VI Road, Ratchathewi, Bangkok, 10400, Thailand
| | - Chanika Angsanuntsukh
- Department of Orthopaedics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, 270 Rama VI Road, Ratchathewi, Bangkok, 10400, Thailand.
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7
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Liu T, Leung DKY, Lu S, Kwok WW, Sze LCY, Tse SSK, Ng SM, Wong PWC, Lou VWQ, Tang JYM, Wong DFK, Chan WC, Kwok RYK, Lum TYS, Wong GHY. Collaborative community mental health and aged care services with peer support to prevent late-life depression: study protocol for a non-randomised controlled trial. Trials 2022; 23:280. [PMID: 35410292 PMCID: PMC8996671 DOI: 10.1186/s13063-022-06122-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 02/18/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Late-life depression is common, modifiable, yet under-treated. Service silos and human resources shortage contribute to insufficient prevention and intervention. We describe an implementation research protocol of collaborative stepped care and peer support model that integrates community mental health and aged care services to address service fragmentation, using productive ageing and recovery principles to involve older people as peer supporters to address human resource issue.
Methods/design
This is a non-randomised controlled trial examining the effectiveness and cost-effectiveness of the “Jockey Club Holistic Support Project for Elderly Mental Wellness” (JC JoyAge) model versus care as usual (CAU) in community aged care and community mental health service units in 12 months. Older people aged 60 years and over with mild to moderate depressive symptoms or risk factors for developing depression will be included. JoyAge service users will receive group-based activities and psychoeducation, low-intensity psychotherapy, or high-intensity psychotherapy according to the stepped care protocol in addition to usual community mental health or aged care, with support from an older peer supporter. The primary clinical outcome, depressive symptoms, and secondary outcomes, self-harm risk, anxiety symptoms, and loneliness, will be measured with the Patient Health Questionnaire-9 (PHQ-9), Self-Harm Inventory, Generalized Anxiety Disorder 7-item scale (GAD-7), and UCLA Loneliness 3-item scale (UCLA-3) respectively. Cost-effectiveness analysis will assess health-related quality of life using the EQ-5D-5L and service utilisation using the Client Service Receipt Inventory (CSRI). We use multilevel linear mixed models to compare outcomes change between groups and calculate the incremental cost-effectiveness ratio in terms of quality-adjusted life years.
Discussion
This study will provide evidence about outcomes for older persons with mental health needs receiving collaborative stepped care service without silos and with trained young-old volunteers to support engagement, treatment, and transitions. Cost-effectiveness findings from this study will inform resource allocation in this under-treated population.
Trial registration
ClinicalTrials.gov NCT03593889. Registered on 20 July 2018.
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Morciano A, Moerbeek M. Optimal allocation to treatments in a sequential multiple assignment randomized trial. Stat Methods Med Res 2021; 30:2471-2484. [PMID: 34554015 PMCID: PMC8649474 DOI: 10.1177/09622802211037066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
One of the main questions in the design of a trial is how many subjects should be
assigned to each treatment condition. Previous research has shown that equal
randomization is not necessarily the best choice. We study the optimal
allocation for a novel trial design, the sequential multiple assignment
randomized trial, where subjects receive a sequence of treatments across various
stages. A subject's randomization probabilities to treatments in the next stage
depend on whether he or she responded to treatment in the current stage. We
consider a prototypical sequential multiple assignment randomized trial design
with two stages. Within such a design, many pairwise comparisons of treatment
sequences can be made, and a multiple-objective optimal design strategy is
proposed to consider all such comparisons simultaneously. The optimal design is
sought under either a fixed total sample size or a fixed budget. A Shiny App is
made available to find the optimal allocations and to evaluate the efficiency of
competing designs. As the optimal design depends on the response rates to
first-stage treatments, maximin optimal design methodology is used to find
robust optimal designs. The proposed methodology is illustrated using a
sequential multiple assignment randomized trial example on weight loss
management.
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Affiliation(s)
| | - Mirjam Moerbeek
- Department of Methodology and Statistics, Utrecht University, the Netherlands
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9
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Ryeznik Y, Sverdlov O, Svensson EM, Montepiedra G, Hooker AC, Wong WK. Pharmacometrics meets statistics-A synergy for modern drug development. CPT-PHARMACOMETRICS & SYSTEMS PHARMACOLOGY 2021; 10:1134-1149. [PMID: 34318621 PMCID: PMC8520751 DOI: 10.1002/psp4.12696] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 05/17/2021] [Accepted: 07/02/2021] [Indexed: 01/20/2023]
Abstract
Modern drug development problems are very complex and require integration of various scientific fields. Traditionally, statistical methods have been the primary tool for design and analysis of clinical trials. Increasingly, pharmacometric approaches using physiology-based drug and disease models are applied in this context. In this paper, we show that statistics and pharmacometrics have more in common than what keeps them apart, and collectively, the synergy from these two quantitative disciplines can provide greater advances in clinical research and development, resulting in novel and more effective medicines to patients with medical need.
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Affiliation(s)
- Yevgen Ryeznik
- BioPharma Early Biometrics and Statistical Innovation, Data Science & AI, R&D Biopharmaceuticals, AstraZeneca, Gothenburg, Sweden
| | - Oleksandr Sverdlov
- Early Development Analytics, Novartis Pharmaceuticals Corporation, East Hanover, New Jersey, USA
| | - Elin M Svensson
- Department of Pharmacy, Uppsala University, Uppsala, Sweden.,Department of Pharmacy, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Grace Montepiedra
- Center for Biostatistics in AIDS Research, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | | | - Weng Kee Wong
- Department of Biostatistics, University of California Los Angeles, Los Angeles, California, USA
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10
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Optimal allocations for two treatment comparisons within the proportional odds cumulative logits model. PLoS One 2021; 16:e0250119. [PMID: 33882086 PMCID: PMC8059828 DOI: 10.1371/journal.pone.0250119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 03/30/2021] [Indexed: 12/02/2022] Open
Abstract
This paper studies optimal treatment allocations for two treatment comparisons when the outcome is ordinal and analyzed by a proportional odds cumulative logits model. The variance of the treatment effect estimator is used as optimality criterion. The optimal design is sought so that this variance is minimal for a given total sample size or a given budget, meaning that the power for the test on treatment effect is maximal, or it is sought so that a required power level is achieved at a minimal total sample size or budget. Results are presented for three, five and seven ordered response categories, three treatment effect sizes and a skewed, bell-shaped or polarized distribution of the response probabilities. The optimal proportion subjects in the intervention condition decreases with the number of response categories and the costs for the intervention relative to those for the control. The relation between the optimal proportion and effect size depends on the distribution of the response probabilities. The widely used balanced design is not always the most efficient; its efficiency as compared to the optimal design decreases with increasing cost ratio. The optimal design is highly robust to misspecification of the response probabilities and treatment effect size. The optimal design methodology is illustrated using two pharmaceutical examples. A Shiny app is available to find the optimal treatment allocation, to evaluate the efficiency of the balanced design and to study the relation between budget or sample size and power.
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11
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Frieri R, Zagoraiou M. Optimal and ethical designs for hypothesis testing in multi-arm exponential trials. Stat Med 2021; 40:2578-2603. [PMID: 33687086 DOI: 10.1002/sim.8919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 01/25/2021] [Accepted: 02/03/2021] [Indexed: 11/06/2022]
Abstract
Multi-arm clinical trials are complex experiments which involve several objectives. The demand for unequal allocations in a multi-treatment context is growing and adaptive designs are being increasingly used in several areas of medical research. For uncensored and censored exponential responses, we propose a constrained optimization approach in order to derive the design maximizing the power of the multivariate test of homogeneity, under a suitable ethical constraint. In the absence of censoring, we obtain a very simple closed-form solution that dominates the balanced design in terms of power and ethics. Our suggestion can also accommodate delayed responses and staggered entries, and can be implemented via response adaptive rules. While other targets proposed in the literature could present an unethical behavior, the suggested optimal allocation is frequently unbalanced by assigning more patients to the best treatment, both in the absence and presence of censoring. We evaluate the operating characteristics of our proposal theoretically and by simulations, also redesigning a real lung cancer trial, showing that the constrained optimal target guarantees very good performances in terms of ethical demands, power and estimation precision. Therefore, it is a valid and useful tool in designing clinical trials, especially oncological trials and clinical experiments for grave and novel infectious diseases, where the ethical concern is of primary importance.
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Affiliation(s)
- Rosamarie Frieri
- Department of Statistical Sciences, University of Bologna, Bologna, Italy
| | - Maroussa Zagoraiou
- Department of Statistical Sciences, University of Bologna, Bologna, Italy
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12
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Sverdlov O, Ryeznik Y, Wong WK. On Optimal Designs for Clinical Trials: An Updated Review. JOURNAL OF STATISTICAL THEORY AND PRACTICE 2019. [DOI: 10.1007/s42519-019-0073-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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