Few studies have employed a controlled experimental design to test the effectiveness of unconditional cash incentives on the rates of participation in web surveys. Even fewer studies have looked at ...the effects of these incentives on nonresponse bias in web surveys. This article addresses these two underresearched areas by utilizing two separate sources of data on a random sample of college students. Specifically, we examine the impact of prepaid token incentives on response rates to a web survey and compare survey data on respondents to administrative records of all sampled persons. Results support the use of unconditional incentives in web surveys as an effective way to improve response. However, contrary to several studies on the relationship between token incentives and nonresponse bias, our findings suggest that prepaid cash incentives may actually produce data that are less representative of the target population.
Abstract The purpose of this study was to assess the intra-rater and inter-rater reliability of electronic and manual dynamometry and goniometry in healthy volunteers, and the inter-instrument ...reliability in the assessment of healthy volunteers and patients recovering after a fracture of the distal radius. Grip strength, grip fatigue, pinch strength and range of motion were assessed in all participants with both the manual and electronic instruments by two physiotherapists and orthopaedic specialist trainee. The measures of dynamometry demonstrated excellent reliability (intra-class correlation coefficient >0.90), with the instruments found to be interchangeable with the exception of the grip fatigue. Variable intra-rater and inter-rater reliability was demonstrated with all planes of movement for the goniometry measures regardless of the instrument used. The results of this study support the continued use of dynamometry in the clinical setting, but raise questions regarding the use of goniometry measurements. Level of evidence Diagnostic level III
Regulatory authorities require that the sample size of a confirmatory trial is calculated prior to the start of the trial. However, the sample size quite often depends on parameters that might not be ...known in advance of the study. Misspecification of these parameters can lead to under‐ or overestimation of the sample size. Both situations are unfavourable as the first one decreases the power and the latter one leads to a waste of resources. Hence, designs have been suggested that allow a re‐assessment of the sample size in an ongoing trial. These methods usually focus on estimating the variance. However, for some methods the performance depends not only on the variance but also on the correlation between measurements. We develop and compare different methods for blinded estimation of the correlation coefficient that are less likely to introduce operational bias when the blinding is maintained. Their performance with respect to bias and standard error is compared to the unblinded estimator. We simulated two different settings: one assuming that all group means are the same and one assuming that different groups have different means. Simulation results show that the naïve (one‐sample) estimator is only slightly biased and has a standard error comparable to that of the unblinded estimator. However, if the group means differ, other estimators have better performance depending on the sample size per group and the number of groups.
Background
A balloon spacer is a relatively simple addition to an arthroscopic debridement procedure for irreparable rotator cuff tears.
Objective
To evaluate the clinical and cost-effectiveness of a ...subacromial balloon spacer for individuals undergoing arthroscopic debridement for irreparable rotator cuff tears.
Design
A multicentre participant-and assessor-blinded randomised controlled trial comparing arthroscopic debridement with the InSpace
®
(Stryker, Kalamazoo, MI, USA) balloon to arthroscopic debridement alone, using a novel adaptive design. Pretrial simulations informed stopping boundaries for two interim analyses, using outcome data from early and late time points.
Setting
A total of 24 NHS centres.
Participants
Adults with a symptomatic, irreparable rotator cuff tear for whom conservative management had been unsuccessful.
Interventions
Arthroscopic debridement of the subacromial space plus insertion of the InSpace balloon compared with arthroscopic debridement alone.
Main outcome measures
Oxford Shoulder Score at 12 months.
Results
A predefined stopping boundary was met at the first interim analysis. Recruitment stopped with 117 participants randomised. We obtained primary outcome data on 114 participants (97%). The mean Oxford Shoulder Score at 12 months was 34.3 in the debridement-only group (59 participants of 61 randomised) and 30.3 in the debridement with balloon group (55 participants of 56 randomised; mean difference: −4.2; 95% confidence interval −8.2 to −0.26;
p
= 0.037). There was no difference in safety events. In the cost-effectiveness analysis, debridement-only dominated with a probability of <1% that the device is cost-effective.
Magnetic resonance imaging substudy
To evaluate the function of the balloon, we developed a dynamic magnetic resonance imaging protocol to induce humeral movement by activating the deltoid. The pandemic restricted recruitment, so the sample size was small (
n
= 17).
Statistical methodology study
We applied the novel adaptive design approach to data from seven previous randomised controlled trials. The method would have been applicable to five of these trials and would have made substantial savings in time to recruitment, without compromising the main findings of the included trials.
Interim analysis interpretation study
We asked potential data monitoring committee members to review interim analysis reports presented using Bayesian and frequentist frameworks. They did not always follow the stopping rules and would benefit from additional information to support decision-making.
Limitations
The InSpace balloon could be beneficial in a different population although we are not aware of it being widely used for other purposes. As a result of the pandemic, we were not able to complete data collection for objective measures.
Conclusions
In this efficient adaptive trial, clinical and cost-effectiveness favoured the control treatment without the InSpace balloon. Therefore, we do not recommend this device for the treatment of irreparable rotator cuff tears.
Future work
There is an urgent need for high-quality research into interventions for people with irreparable rotator cuff tears as there is a lack of good evidence for all available treatment options at present.
Trial registration
This trial is registered as ISRCTN17825590.
Funding
This project (project reference 16/61/18) was funded by the Efficacy and Mechanism Evaluation (EME) Programme, a Medical Research Council and National Institute for Health and Care Research (NIHR) partnership. The trial is co-sponsored by the University of Warwick and University Hospitals Coventry and Warwickshire NHS Trust. This study will be published in full in
Efficacy and Mechanism Evaluation
; Vol. 10, No 3. See the NIHR Journals Library website for further project information.
Distal femoral fractures are a source of considerable morbidity and best treatment is currently uncertain. The Trial of Acute Femoral Fracture Fixation (TrAFFix) is a randomised, parallel-group ...feasibility study designed to inform the design of a later, definitive clinical trial comparing intramedullary nails and locking plates for the treatment of distal femoral fractures.
Patients aged 50 years and older with a femoral fracture within the distal two Müller squares are potentially eligible for inclusion. Participants are randomly allocated to receive fixation with either an intramedullary nail or a distal locking plate. Measurements (EuroQol 5 Dimensions, Dementia Quality of Life, Disability Rating Index) are collected at baseline, 6 weeks and 4 months. The recruitment rate will be assessed across seven participating centres over a total of 52 centre-months which is expected after 10 months of recruitment. Objectives are - feasibility phase, to assess recruitment rate and completion rate of the primary outcome measure; process evaluation, to assess the generalisability and likely success of a future trial; definitive trial, quantify and draw inferences on observed differences in health-related quality of life at 4 months between the study intervention groups (nail versus plate). A favourable opinion was granted by the Wales Research Ethics Committee (16/WA/0225), study-wide NHS approval was given by the Health Research Authority (IRAS 206745), and participating NHS trusts provided local approvals. This study was funded by the National Institute for Health Research Health Technology Assessment (HTA 15/59/22).
This is the protocol for a feasibility study conducted prior to any future definitive trial. The estimates of participant recruitment rate and proportion of data completion will be coupled with outputs from the process evaluation to make a final decision regarding feasibility TRIAL REGISTRATIONS: The study is registered with the National Institute for Health Research Portfolio (CPMS ID: 32536) and the ISRCTN registry ( ISRCTN92089567 ) on 26 May 2016.
Microvascular blood flow in normal and pathologic rotator cuffs Karthikeyan, Shanmugam, MRCS; Griffin, Damian R., MPhil, FRCS (Tr & Orth); Parsons, Nicholas, PhD ...
Journal of shoulder and elbow surgery,
12/2015, Letnik:
24, Številka:
12
Journal Article
Recenzirano
Background Microvascular blood flow in the tendon plays an important role in the pathogenesis of rotator cuff abnormalities. There are conflicting views about the presence of a hypovascular zone in ...the supraspinatus tendon. Besides, no studies have looked at the pattern of blood flow around a partial-thickness tear. Our aim was to measure microvascular blood flow in normal and a range of pathologic rotator cuff tendons using laser doppler flowmetry. Methods A total of 120 patients having arthroscopic shoulder surgery were divided into 4 equal groups on the basis of their intraoperative diagnosis: normal rotator cuff, subacromial impingement syndrome, and partial-thickness or full-thickness rotator cuff tear. Microvascular blood flow was measured at 5 different regions of each cuff using a laser doppler probe. The values were compared to assess variability within and between individuals. Results Total blood flow was greater in the normal rotator cuff group compared with the groups with pathologic rotator cuffs, with the largest difference seen in the subacromial impingement group. Within individuals, blood flow was highest at the musculotendinous junction and lowest at the lateral insertional part of the tendon. Among groups, the blood flow was significantly lower at the anteromedial and posteromedial cuff in the groups with impingement and full-thickness tears compared with the group with normal cuff. Conclusion Real-time in vivo laser doppler analysis has shown that microvascular blood flow is not uniform throughout the supraspinatus tendon. Blood flow in the pathologic supraspinatus tendon was significantly lower compared with the normal tendon.
Political scientists and legal scholars have long argued that law “in
practice” is primarily dictated by non-legal factors in Indonesia. While
this remains largely true in post-Suharto Indonesia, it ...no longer appears to
describe accurately the operation of the legal system in all cases. Law is
becoming more relevant in new types of cases in which the state fights itself,
such as in disputes between central and regional government over jurisdiction.
However, the increasing space for and resort to law has highlighted major
shortcomings of the rules for delineating and enforcing the powers and
responsibilities of state institutions.
Randomised controlled trials are being increasingly used to evaluate new surgical interventions. There are a number of problematic methodological issues specific to surgical trials, the most ...important being identifying whether patients are eligible for recruitment into the trial. This is in part due to the diversity in practice patterns across institutions and the enormous range of available interventions that often leads to a low level of agreement between clinicians about both the value and the appropriate choice of intervention. We argue that a clinician should offer patients the option of recruitment into a trial, even if the clinician is not individually in a position of equipoise, if there is collective (clinical) equipoise amongst the wider clinical community about the effectiveness of a proposed intervention (the clinical equipoise principle). We show how this process can work using data collected from an ongoing trial of a surgical intervention.
We describe a statistical framework for the assessment of uncertainty prior to patient recruitment to a clinical trial using a panel of expert clinical assessors and techniques for eliciting, pooling and modelling of expert opinions. The methodology is illustrated using example data from the UK Heel Fracture Trial. The statistical modelling provided results that were clear and simple to present to clinicians and showed how decisions regarding recruitment were influenced by both the collective opinion of the expert panel and the type of decision rule selected.
The statistical framework presented has potential to identify eligible patients and assist in the simplification of eligibility criteria which might encourage greater participation in clinical trials evaluating surgical interventions.
IntroductionThe treatment of displaced, extra-articular fractures of the distal tibia remains controversial. These injuries are difficult to manage due to limited soft tissue cover, poor vascularity ...of the area and proximity to the ankle joint. Surgical treatment options are expanding and include locked intramedullary nails, plate and screw fixation and external fixator systems. The nail and plate options are most commonly used in the UK, but controversy exists over which treatment is most clinically and cost-effective. In this multicentre randomised controlled trial we aim to assess ratings of disability 6 months postinjury in patients who have sustained a distal tibia fracture treated with either an intramedullary nail or plate and locking screw fixation.Methods and analysisAdult patients presenting at trial centres with an acute fracture of the distal tibia will be considered for inclusion. A total of 320 patients will provide 90% power to detect a difference of 8 points in Disability Rating Index (DRI) score at 6 months at the 5% level. The randomisation sequence is stratified by trial centre and age, and administered via web-based service with 1:1 treatment allocation. Baseline demographic and pre-injury functional data and radiographs will be collected using the DRI, Olerud and Molander, and EuroQol EQ-5D questionnaire. Clinical assessment, early complications and radiographs will be recorded at 6–8 weeks. Functional outcome, health-related quality of life and resource use will be collected at 3, 6 and 12 months postoperatively. The main analysis will investigate differences in DRI 6 months postsurgery, between the two treatment groups, on an intention-to-treat basis. Tests will be two-sided and considered to provide evidence for a significant difference if p values are <0.05.Ethics and disseminationNRES Committee West-Midlands, 6/11/2012 (ref:12/WM/0340). The results of the trial will be disseminated via peer-reviewed publications and presentations at relevant conferences.Trial registration numberISRCTN99771224.
Adaptive seamless designs combine confirmatory testing, a domain of phase III trials, with features such as treatment or subgroup selection, typically associated with phase II trials. They promise to ...increase the efficiency of development programmes of new drugs, for example, in terms of sample size and/or development time. It is well acknowledged that adaptive designs are more involved from a logistical perspective and require more upfront planning, often in the form of extensive simulation studies, than conventional approaches. Here, we present a framework for adaptive treatment and subgroup selection using the same notation, which links the somewhat disparate literature on treatment selection on one side and on subgroup selection on the other. Furthermore, we introduce a flexible and efficient simulation model that serves both designs. As primary endpoints often take a long time to observe, interim analyses are frequently informed by early outcomes. Therefore, all methods presented accommodate interim analyses informed by either the primary outcome or an early outcome. The R package asd, previously developed to simulate designs with treatment selection, was extended to include subgroup selection (so‐called adaptive enrichment designs). Here, we describe the functionality of the R package asd and use it to present some worked‐up examples motivated by clinical trials in chronic obstructive pulmonary disease and oncology. The examples both illustrate various features of the R package and provide insights into the operating characteristics of adaptive seamless studies.
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