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1.
BMC Geriatr ; 24(1): 369, 2024 Apr 24.
Article En | MEDLINE | ID: mdl-38658827

BACKGROUND: Regular exercise is emphasized for the improvement of functional capacity and independence of older adults. This study aimed to compare the effects of a dual-task resistance exercise program and resistance exercise on cognition, mood, depression, physical function, and activities of daily living (ADL) in older adults with cognitive impairment. METHODS: A total of 44 older adults participated in the study. Participants were randomly allocated to an experimental group (n = 22) performing a dual-task resistance exercise program for cognitive function improvement and a control group (n = 22) performing a resistance exercise program. Both groups performed the exercise for 40 min per session, three times a week, for 6 weeks (18 sessions). Cognition, mood, depression, functional fitness, and ADL were quantified before and after the intervention using the Mini-Mental State Examination (MMSE), profile of mood states (POMS), geriatric depression scale (GDS), senior fitness test (SFT), and Korean version of ADL, respectively. RESULTS: There was a significant time and group interaction on the MMSE (p = 0.044). There were no significant time and group interactions in the POMS, GDS, SFT, or ADL. Cognitive function (p < 0.001), mood (p < 0.001), depression (p < 0.001), functional fitness (p < 0.001), and ADL (p < 0.001) significantly improved after dual-task resistance exercise, and cognitive function (p < 0.001), mood (p < 0.001), depression (p < 0.001), functional fitness (p < 0.001), and ADL (p < 0.001) significantly improved after resistance exercise. CONCLUSIONS: Dual-task resistance exercise is more effective than resistance exercise in improving cognitive function in older adults with cognitive impairment. Both dual-task resistance exercise and resistance exercise improves mood, depression, functional fitness, and ADL after the intervention. We propose using dual-task resistance exercises for cognitive and physical health management in the older adults with cognitive impairment. TRIAL REGISTRATION: This study was registered with the Clinical Research Information Service (WHO International Clinical Trials Registry Platform) (Registration ID, KCT0005389; Registration date, 09/09/2020).


Activities of Daily Living , Affect , Cognition , Cognitive Dysfunction , Depression , Physical Fitness , Resistance Training , Humans , Aged , Male , Activities of Daily Living/psychology , Female , Cognitive Dysfunction/therapy , Cognitive Dysfunction/psychology , Resistance Training/methods , Depression/therapy , Depression/psychology , Cognition/physiology , Physical Fitness/physiology , Physical Fitness/psychology , Affect/physiology , Single-Blind Method , Aged, 80 and over
2.
Phys Rev Lett ; 131(17): 170602, 2023 Oct 27.
Article En | MEDLINE | ID: mdl-37955505

We present experimental demonstrations of accurate and unambiguous single-shot discrimination between three quantum channels using a single trapped ^{40}Ca^{+} ion. The three channels cannot be distinguished unambiguously using repeated single channel queries, the natural classical analogue. We develop techniques for using the six-dimensional D_{5/2} state space for quantum information processing, and we implement protocols to discriminate quantum channel analogues of phase shift keying and amplitude shift keying data encodings used in classical radio communication. The demonstrations achieve discrimination accuracy exceeding 99% in each case, limited entirely by known experimental imperfections.

3.
Stat Sci ; 38(2): 185-208, 2023 May.
Article En | MEDLINE | ID: mdl-37324576

Response-Adaptive Randomization (RAR) is part of a wider class of data-dependent sampling algorithms, for which clinical trials are typically used as a motivating application. In that context, patient allocation to treatments is determined by randomization probabilities that change based on the accrued response data in order to achieve experimental goals. RAR has received abundant theoretical attention from the biostatistical literature since the 1930's and has been the subject of numerous debates. In the last decade, it has received renewed consideration from the applied and methodological communities, driven by well-known practical examples and its widespread use in machine learning. Papers on the subject present different views on its usefulness, and these are not easy to reconcile. This work aims to address this gap by providing a unified, broad and fresh review of methodological and practical issues to consider when debating the use of RAR in clinical trials.

4.
Am J Health Behav ; 47(1): 21-29, 2023 02 28.
Article En | MEDLINE | ID: mdl-36945096

Objectives: The primary purpose of this study was to explore the mediating roles of resilience and physical activity (PA) levels on the subjective health of people with spinal cord injury(SCI) during the COVID-19 pandemic.Methods: A total of 201 Koreans with SCI completed a survey between February and April 2021. The questionnaire measured participants' PA levels before and during the COVID-19 pandemic, resilience, and subjective health assessment. The data were analyzed using SPSS, and PROCESS macro (Model 6) was used to determine the dual mediation effects. Results: PA levels before COVID-19 positively affected resilience and PA levels during COVID-19, and resilience positively affected PA levels during COVID-19 and subjective health. PA levels during COVID-19 had a positive influence on subjective health. Moreover, resilience and PA levels during COVID-19 were independent mediators of the relationship between PA levels before COVID-19 and subjective health. PA levels before COVID-19 indirectly affected subjective health through a dual-mediated pathway of resilience and PA levels during COVID-19. Conclusion: We suggest that it is necessary to promote regular PA for people with physical disabilities to enhance resilience, and thus, maintain a healthy life even during a public health crisis.


COVID-19 , Spinal Cord Injuries , Humans , East Asian People , Pandemics , Exercise
5.
Stat Med ; 42(8): 1156-1170, 2023 04 15.
Article En | MEDLINE | ID: mdl-36732886

In some clinical scenarios, for example, severe sepsis caused by extensively drug resistant bacteria, there is uncertainty between many common treatments, but a conventional multiarm randomized trial is not possible because individual participants may not be eligible to receive certain treatments. The Personalised Randomized Controlled Trial design allows each participant to be randomized between a "personalised randomization list" of treatments that are suitable for them. The primary aim is to produce treatment rankings that can guide choice of treatment, rather than focusing on the estimates of relative treatment effects. Here we use simulation to assess several novel analysis approaches for this innovative trial design. One of the approaches is like a network meta-analysis, where participants with the same personalised randomization list are like a trial, and both direct and indirect evidence are used. We evaluate this proposed analysis and compare it with analyses making less use of indirect evidence. We also propose new performance measures including the expected improvement in outcome if the trial's rankings are used to inform future treatment rather than random choice. We conclude that analysis of a personalized randomized controlled trial can be performed by pooling data from different types of participants and is robust to moderate subgroup-by-intervention interactions based on the parameters of our simulation. The proposed approach performs well with respect to estimation bias and coverage. It provides an overall treatment ranking list with reasonable precision, and is likely to improve outcome on average if used to determine intervention policies and guide individual clinical decisions.


Randomized Controlled Trials as Topic , Research Design , Humans , Precision Medicine , Patient Participation
6.
Health Care Women Int ; 44(1): 28-45, 2023 01.
Article En | MEDLINE | ID: mdl-32275487

Although leisure provides numerous advantages, people sometimes feel guilty while engaging in leisure. The study objective was to explore the gender differences in the effects of socio-demographic factors and motivational factors on leisure guilt in Korea. Results showed that socio-demographic factors and leisure motivations influenced leisure guilt and the influence of these factors was different by gender. While age, number of children, and household income significantly influenced men's leisure guilt, only leisure expenditure did for women. When motivation was entered, only development and separation motivation were significant for men and adventure and relaxation motivation were significant for women.


Guilt , Motivation , Male , Child , Humans , Female , Leisure Activities , Demography , Republic of Korea
7.
PLoS One ; 17(9): e0274272, 2022.
Article En | MEDLINE | ID: mdl-36094920

When comparing the performance of multi-armed bandit algorithms, the potential impact of missing data is often overlooked. In practice, it also affects their implementation where the simplest approach to overcome this is to continue to sample according to the original bandit algorithm, ignoring missing outcomes. We investigate the impact on performance of this approach to deal with missing data for several bandit algorithms through an extensive simulation study assuming the rewards are missing at random. We focus on two-armed bandit algorithms with binary outcomes in the context of patient allocation for clinical trials with relatively small sample sizes. However, our results apply to other applications of bandit algorithms where missing data is expected to occur. We assess the resulting operating characteristics, including the expected reward. Different probabilities of missingness in both arms are considered. The key finding of our work is that when using the simplest strategy of ignoring missing data, the impact on the expected performance of multi-armed bandit strategies varies according to the way these strategies balance the exploration-exploitation trade-off. Algorithms that are geared towards exploration continue to assign samples to the arm with more missing responses (which being perceived as the arm with less observed information is deemed more appealing by the algorithm than it would otherwise be). In contrast, algorithms that are geared towards exploitation would rapidly assign a high value to samples from the arms with a current high mean irrespective of the level observations per arm. Furthermore, for algorithms focusing more on exploration, we illustrate that the problem of missing responses can be alleviated using a simple mean imputation approach.


Algorithms , Computer Simulation , Humans , Research , Reward
8.
Stat Methods Med Res ; 31(11): 2104-2121, 2022 11.
Article En | MEDLINE | ID: mdl-35876412

Covariate adjustment via a regression approach is known to increase the precision of statistical inference when fixed trial designs are employed in randomized controlled studies. When an adaptive multi-arm design is employed with the ability to select treatments, it is unclear how covariate adjustment affects various aspects of the study. Consider the design framework that relies on pre-specified treatment selection rule(s) and a combination test approach for hypothesis testing. It is our primary goal to evaluate the impact of covariate adjustment on adaptive multi-arm designs with treatment selection. Our secondary goal is to show how the Uniformly Minimum Variance Conditionally Unbiased Estimator can be extended to account for covariate adjustment analytically. We find that adjustment with different sets of covariates can lead to different treatment selection outcomes and hence probabilities of rejecting hypotheses. Nevertheless, we do not see any negative impact on the control of the familywise error rate when covariates are included in the analysis model. When adjusting for covariates that are moderately or highly correlated with the outcome, we see various benefits to the analysis of the design. Conversely, there is negligible impact when including covariates that are uncorrelated with the outcome. Overall, pre-specification of covariate adjustment is recommended for the analysis of adaptive multi-arm design with treatment selection. Having the statistical analysis plan in place prior to the interim and final analyses is crucial, especially when a non-collapsible measure of treatment effect is considered in the trial.


Research Design , Probability , Treatment Outcome , Patient Selection , Computer Simulation
9.
Article En | MEDLINE | ID: mdl-35742452

Due to the ongoing COVID-19 pandemic, many online programs for social meetings, education, leisure, and physical activities have been developed and provided; however, children with cerebral palsy (CP) cannot enjoy online programs in the same way that those without disabilities can. The aim of this study was to investigate the differences in reintegration to normal living (RNL), social interaction, and quality of life among school-age children with CP after participation in a game-based online−offline hybrid group exercise program. The current study was conducted on 26 children with CP who participated in a hybrid exercise program. The RNL, social interaction, and quality of life were measured before and after the six-week program. The scores of RNL and quality of life were improved (p < 0.05) after program participation. Online or hybrid exercise programs incorporating interactive methods (i.e., competition and cooperating) could enhance RNL and quality of life of children with CP. Thus, well-designed online or hybrid exercise programs should be developed and provided for children with CP to enhance overall quality of life during the pandemic.


COVID-19 , Cerebral Palsy , Wheelchairs , COVID-19/epidemiology , Cerebral Palsy/epidemiology , Cerebral Palsy/therapy , Child , Exercise , Exercise Therapy/methods , Humans , Pandemics , Quality of Life , Republic of Korea/epidemiology
10.
Insights Imaging ; 13(1): 80, 2022 Apr 25.
Article En | MEDLINE | ID: mdl-35467253

Endometrial carcinoma is the most common gynaecological cancer in developed countries. Most cases are low-volume/low-grade tumour at presentation; however, high-grade subtypes may present with locally advanced disease with higher propensity for spread outside of the pelvis. MRI has a role in local staging of the tumour and helping the clinicians in treatment decision making. This pictorial essay gives examples of endometrial carcinoma at different stages with histological correlation. It also explores the potential limitations and pitfalls of imaging in this context.

11.
Stat Med ; 41(5): 877-890, 2022 02 28.
Article En | MEDLINE | ID: mdl-35023184

Adapting the final sample size of a trial to the evidence accruing during the trial is a natural way to address planning uncertainty. Since the sample size is usually determined by an argument based on the power of the trial, an interim analysis raises the question of how the final sample size should be determined conditional on the accrued information. To this end, we first review and compare common approaches to estimating conditional power, which is often used in heuristic sample size recalculation rules. We then discuss the connection of heuristic sample size recalculation and optimal two-stage designs, demonstrating that the latter is the superior approach in a fully preplanned setting. Hence, unplanned design adaptations should only be conducted as reaction to trial-external new evidence, operational needs to violate the originally chosen design, or post hoc changes in the optimality criterion but not as a reaction to trial-internal data. We are able to show that commonly discussed sample size recalculation rules lead to paradoxical adaptations where an initially planned optimal design is not invariant under the adaptation rule even if the planning assumptions do not change. Finally, we propose two alternative ways of reacting to newly emerging trial-external evidence in ways that are consistent with the originally planned design to avoid such inconsistencies.


Friends , Research Design , Humans , Sample Size , Uncertainty
12.
Anesthesiology ; 136(1): 148-161, 2022 01 01.
Article En | MEDLINE | ID: mdl-34724559

BACKGROUND: The relationship between late clinical outcomes after injury and early dynamic changes between fibrinolytic states is not fully understood. The authors hypothesized that temporal transitions in fibrinolysis states using rotational thromboelastometry (ROTEM) would aid stratification of adverse late clinical outcomes and improve understanding of how tranexamic acid modulates the fibrinolytic response and impacts mortality. METHODS: The authors conducted a secondary analysis of previously collected data from trauma patients enrolled into an ongoing prospective cohort study (International Standard Randomised Controlled Trial Number [ISRCTN] 12962642) at a major trauma center in the United Kingdom. ROTEM was performed on admission and at 24 h with patients retrospectively grouped into three fibrinolysis categories: tissue factor-activated ROTEM maximum lysis of less than 5% (low); tissue factor-activated ROTEM maximum lysis of 5 to 15% (normal); or tissue factor-activated ROTEM maximum lysis of more than 15% (high). Primary outcomes were multiorgan dysfunction syndrome and 28-day mortality. RESULTS: Seven-hundred thirty-one patients were included: 299 (41%) were treated with tranexamic acid and 432 (59%) were untreated. Two different cohorts with low-maximum lysis at 24 h were identified: (1) severe brain injury and (2) admission shock and hemorrhage. Multiple organ dysfunction syndrome was greatest in those with low-maximum lysis on admission and at 24 h, and late mortality was four times higher than in patients who remained normal during the first 24 h (7 of 42 [17%] vs. 9 of 223 [4%]; P = 0.029). Patients that transitioned to or remained in low-maximum lysis had increased odds of organ dysfunction (5.43 [95% CI, 1.43 to 20.61] and 4.85 [95% CI, 1.83 to 12.83], respectively). Tranexamic acid abolished ROTEM hyperfibrinolysis (high) on admission, increased the frequency of persistent low-maximum lysis (67 of 195 [34%]) vs. 8 of 79 [10%]; P = 0.002), and was associated with reduced early mortality (28 of 195 [14%] vs. 23 of 79 [29%]; P = 0.015). No increase in late deaths, regardless of fibrinolysis transition patterns, was observed. CONCLUSIONS: Adverse late outcomes are more closely related to 24-h maximum lysis, irrespective of admission levels. Tranexamic acid alters early fibrinolysis transition patterns, but late mortality in patients with low-maximum lysis at 24 h is not increased.


Fibrinolysis/physiology , Hemorrhage/blood , Hemorrhage/mortality , Wounds and Injuries/blood , Wounds and Injuries/mortality , Adult , Antifibrinolytic Agents/administration & dosage , Blood Coagulation Tests/trends , Cohort Studies , Female , Fibrinolysis/drug effects , Hemorrhage/prevention & control , Humans , Male , Middle Aged , Prospective Studies , Retrospective Studies , Thrombelastography/drug effects , Thrombelastography/trends , Time Factors , Tranexamic Acid/administration & dosage , United Kingdom/epidemiology , Wounds and Injuries/drug therapy
13.
Int J Qual Stud Health Well-being ; 16(1): 1945725, 2021 Dec.
Article En | MEDLINE | ID: mdl-34261425

Purpose: Prior research provides limited information on the roles that leisure can play among Western international students studying in Eastern countries. Exploring this directional difference can provide its implications for Western international student support. Therefore, the purpose of this study is to explore leisure behaviours and leisure benefits associated with acculturation among Western international students residing in South Korea.Method: Using a purposeful criterion sampling strategy, a total of 18 participants (7 males and 11 females) were recruited. This study employed semi-structured in-depth interviews and a content mapping and content mining question strategy was incorporated.Results: The following core themes were associated with the health benefits of leisure activities experienced by international students living in South Korea: (a) promoting mental health, (b) experiencing dynamics of inter-and intra-group friendships, and (c) facilitating acculturation.Conclusions: The findings showed that participants developed friendships with the host individuals and other international students, became well acculturated into a new culture and experienced benefits to their mental health, indicating that leisure participation can be instrumental in improving social and psychological wellbeing.


Acculturation , Leisure Activities , Female , Humans , Male , Mental Health , Republic of Korea , Students
14.
J Clin Med ; 10(11)2021 May 28.
Article En | MEDLINE | ID: mdl-34071351

OBJECTIVE: Pelvic alignment asymmetry in stroke patients negatively affects postural control ability. This study aimed to investigate the effect of posterior pelvic tilt taping on pelvic inclination, muscle strength, and gait ability in stroke patients. METHODS: Forty stroke patients were recruited and randomly divided into the following two groups: the posterior pelvic tilt taping (PPTT) group (n = 20) and the control group (n = 20). All participants underwent sitting-to-standing, indoor walking, and stair walking training (30 min per day, 5 days per week, for 6 weeks). The PPTT group applied posterior pelvic tilt taping during the training period, while the control group did not receive a tape intervention. Pelvic inclination was measured using a palpation meter (PALM). A hand-held dynamometer and the 10-meter walk test were used to measure muscle strength and gait ability. RESULTS: Significantly greater improvements in the pelvic anterior tilt were observed in the PPTT group than in the control group (p < 0.05). Muscle strength in the PPTT group was significantly increased compared to the control group (p < 0.05). Significantly greater improvements in gait speed were observed in the PPTT group than the control group. CONCLUSIONS: According to our results, posterior pelvic tilt taping may be used to improve the anterior pelvic inclination, muscle strength, and gait ability in stroke patients.

15.
Trials ; 22(1): 203, 2021 Mar 10.
Article En | MEDLINE | ID: mdl-33691748

BACKGROUND: Platform trials improve the efficiency of the drug development process through flexible features such as adding and dropping arms as evidence emerges. The benefits and practical challenges of implementing novel trial designs have been discussed widely in the literature, yet less consideration has been given to the statistical implications of adding arms. MAIN: We explain different statistical considerations that arise from allowing new research interventions to be added in for ongoing studies. We present recent methodology development on addressing these issues and illustrate design and analysis approaches that might be enhanced to provide robust inference from platform trials. We also discuss the implication of changing the control arm, how patient eligibility for different arms may complicate the trial design and analysis, and how operational bias may arise when revealing some results of the trials. Lastly, we comment on the appropriateness and the application of platform trials in phase II and phase III settings, as well as publicly versus industry-funded trials. CONCLUSION: Platform trials provide great opportunities for improving the efficiency of evaluating interventions. Although several statistical issues are present, there are a range of methods available that allow robust and efficient design and analysis of these trials.


Data Interpretation, Statistical , Research Design , Clinical Trials as Topic , Humans
16.
Am Stat ; 75(4): 424-432, 2021.
Article En | MEDLINE | ID: mdl-34992303

Sample size derivation is a crucial element of planning any confirmatory trial. The required sample size is typically derived based on constraints on the maximal acceptable Type I error rate and minimal desired power. Power depends on the unknown true effect and tends to be calculated either for the smallest relevant effect or a likely point alternative. The former might be problematic if the minimal relevant effect is close to the null, thus requiring an excessively large sample size, while the latter is dubious since it does not account for the a priori uncertainty about the likely alternative effect. A Bayesian perspective on sample size derivation for a frequentist trial can reconcile arguments about the relative a priori plausibility of alternative effects with ideas based on the relevance of effect sizes. Many suggestions as to how such "hybrid" approaches could be implemented in practice have been put forward. However, key quantities are often defined in subtly different ways in the literature. Starting from the traditional entirely frequentist approach to sample size derivation, we derive consistent definitions for the most commonly used hybrid quantities and highlight connections, before discussing and demonstrating their use in sample size derivation for clinical trials.

17.
Reprod Fertil ; 2(1): 69-80, 2021 01.
Article En | MEDLINE | ID: mdl-35128434

BACKGROUND: Up to 28% of endometriosis patients do not get pain relief from therapeutic laparoscopy but this subgroup is not defined. OBJECTIVES: To identify any prognostic patient-specific factors (such as but not limited to patients' type or location of endometriosis, sociodemographics and lifestyle) associated with a clinically meaningful reduction in post-surgical pain response to operative laparoscopic surgery for endometriosis. SEARCH STRATEGY: PubMed, Cochrane and Embase databases were searched from inception to 19 May 2020 without language restrictions. Backward and forward citation tracking was used. SELECTION CRITERIA DATA COLLECTION AND ANALYSIS: Cohort studies reporting prognostic factors, along with scores for domains of pain associated with endometriosis before and after surgery, were included. Studies that compared surgeries, or laboratory tests, or outcomes without stratification were excluded. Results were synthesised but variation in study designs and inconsistency of outcome reporting precluded us from doing a meta-analysis. MAIN RESULTS: Five studies were included. Quality assessment using the Newcastle-Ottawa scale graded three studies as high, one as moderate and one as having a low risk of bias. Four of five included studies separately reported that a relationship exists between more severe endometriosis and stronger pain relief from laparoscopic surgery. CONCLUSION: Currently, there are few studies of appropriate quality to answer the research question. We recommend future studies report core outcome sets to enable meta-analysis. LAY SUMMARY: Endometriosis is a painful condition caused by displaced cells from the lining of the womb, causing inflammation and scarring inside the body. It affects 6-10% of women and there is no permanent cure. Medical and laparoscopic surgical treatments are available, but about 28% of patients do not get the hoped-for pain relief after surgery. Currently, there is no way of predicting who gets better and who does not. We systematically searched the world literature to establish who may get better, in order to improve counselling when women choose treatment options. We identified five studies of variable quality showing: More complex disease (in specialist hands) responds better to surgery than less, but more studies needed.


Endometriosis , Laparoscopy , Female , Humans , Pelvic Pain , Uterus
18.
BMC Med Res Methodol ; 20(1): 165, 2020 06 24.
Article En | MEDLINE | ID: mdl-32580702

BACKGROUND: Platform trials allow adding new experimental treatments to an on-going trial. This feature is attractive to practitioners due to improved efficiency. Nevertheless, the operating characteristics of a trial that adds arms have not been well-studied. One controversy is whether just the concurrent control data (i.e. of patients who are recruited after a new arm is added) should be used in the analysis of the newly added treatment(s), or all control data (i.e. non-concurrent and concurrent). METHODS: We investigate the benefits and drawbacks of using non-concurrent control data within a two-stage setting. We perform simulation studies to explore the impact of a linear and a step trend on the inference of the trial. We compare several analysis approaches when one includes all the control data or only concurrent control data in the analysis of the newly added treatment. RESULTS: When there is a positive trend and all the control data are used, the marginal power of rejecting the corresponding hypothesis and the type one error rate can be higher than the nominal value. A model-based approach adjusting for a stage effect is equivalent to using concurrent control data; an adjustment with a linear term may not guarantee valid inference when there is a non-linear trend. CONCLUSIONS: If strict error rate control is required then non-concurrent control data should not be used; otherwise it may be beneficial if the trend is sufficiently small. On the other hand, the root mean squared error of the estimated treatment effect can be improved through using non-concurrent control data.


Computer Simulation , Humans
19.
Phys Rev Lett ; 125(24): 243602, 2020 Dec 11.
Article En | MEDLINE | ID: mdl-33412042

Laser decoherence limits the stability of optical clocks by broadening the observable resonance linewidths and adding noise during the dead time between clock probes. Correlation spectroscopy avoids these limitations by measuring correlated atomic transitions between two ensembles, which provides a frequency difference measurement independent of laser noise. Here, we apply this technique to perform stability measurements between two independent clocks based on the ^{1}S_{0}↔^{3}P_{0} transition in ^{27}Al^{+}. By stabilizing the dominant sources of differential phase noise between the two clocks, we observe coherence between them during synchronous Ramsey interrogations as long as 8 s at a frequency of 1.12×10^{15} Hz. The observed contrast in the correlation spectroscopy signal is consistent with the 20.6 s ^{3}P_{0} state lifetime and represents a measurement instability of (1.8±0.5)×10^{-16}/sqrt[τ/s] for averaging periods longer than the probe duration when dead time is negligible.

20.
Stat Med ; 38(18): 3305-3321, 2019 08 15.
Article En | MEDLINE | ID: mdl-31115078

Multiarm clinical trials, which compare several experimental treatments against control, are frequently recommended due to their efficiency gain. In practise, all potential treatments may not be ready to be tested in a phase II/III trial at the same time. It has become appealing to allow new treatment arms to be added into on-going clinical trials using a "platform" trial approach. To the best of our knowledge, many aspects of when to add arms to an existing trial have not been explored in the literature. Most works on adding arm(s) assume that a new arm is opened whenever a new treatment becomes available. This strategy may prolong the overall duration of a study or cause reduction in marginal power for each hypothesis if the adaptation is not well accommodated. Within a two-stage trial setting, we propose a decision-theoretic framework to investigate when to add or not to add a new treatment arm based on the observed stage one treatment responses. To account for different prospect of multiarm studies, we define utility in two different ways; one for a trial that aims to maximise the number of rejected hypotheses; the other for a trial that would declare a success when at least one hypothesis is rejected from the study. Our framework shows that it is not always optimal to add a new treatment arm to an existing trial. We illustrate a case study by considering a completed trial on knee osteoarthritis.


Adaptive Clinical Trials as Topic/methods , Controlled Clinical Trials as Topic/methods , Decision Theory , Adaptive Clinical Trials as Topic/statistics & numerical data , Biostatistics , Clinical Protocols , Controlled Clinical Trials as Topic/statistics & numerical data , Cryotherapy , Humans , Multivariate Analysis , Nerve Block , Osteoarthritis, Knee/physiopathology , Osteoarthritis, Knee/therapy
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