ABSTRACT
BACKGROUND AND OBJECTIVE: Feasibility studies are increasingly being used to support the development of, and investigate uncertainties around, future large-scale trials. The future trial can be designed with either a pragmatic or explanatory mindset. Whereas pragmatic trials aim to inform the choice between different care options and thus, are designed to resemble conditions outside of a clinical trial environment, explanatory trials examine the benefit of a treatment under more controlled conditions. There is existing guidance for designing feasibility studies, but none that explicitly considers the goals of pragmatic designs. We aimed to identify unique areas of uncertainty that are relevant to planning a pragmatic trial. RESULTS: We identified ten relevant domains, partly based on the pragmatic-explanatory continuum indicator summary-2 (PRECIS-2) framework, and describe potential questions of uncertainty within each: intervention development, research ethics, participant identification and eligibility, recruitment of individuals, setting, organization, flexibility of delivery, flexibility of adherence, follow-up, and importance of primary outcome to patients and decision-makers. We present examples to illustrate how uncertainty in these domains might be addressed within a feasibility study. CONCLUSION: Researchers planning a feasibility study in advance of a pragmatic trial should consider feasibility objectives specifically relevant to areas of uncertainty for pragmatic trials.
Subject(s)
Biomedical Research/statistics & numerical data , Biomedical Research/standards , Pragmatic Clinical Trials as Topic/statistics & numerical data , Pragmatic Clinical Trials as Topic/standards , Research Design/statistics & numerical data , Research Design/standards , Uncertainty , Feasibility Studies , Guidelines as Topic , Humans , Pilot ProjectsABSTRACT
OBJECTIVES: To use the Theoretical Domains Framework (TDF) to identify barriers and enablers to participant retention in trials requiring questionnaire return and/or attendance at follow-up clinics. STUDY DESIGN AND SETTING: We invited participants (n = 607) from five pragmatic effectiveness trials, who missed at least one follow-up time point (by not returning a questionnaire and/or not attending a clinic visit), to take part in semistructured telephone interviews. The TDF informed both data collection and analysis. To establish what barriers and enablers most likely influence the target behavior the domain relevance threshold was set at >75% of participants mentioning the domain. RESULTS: Sixteen participants (out of 25 showing interest) were interviewed. Overall, seven theoretical domains were identified as both barriers and enablers to the target behaviors of attending clinic appointments and returning postal questionnaires. Barriers frequently reported in relation to both target behaviours stemmed from participants' knowledge, beliefs about their capabilities and the consequences of performing (or not performing) the behavior. Two domains were identified as salient for questionnaire return only: goals; and memory, attention and decision-making. Emotion was identified as relevant for clinic attendance only. CONCLUSION: This is the first study informed by behavioural science to explore trial participants' accounts of trial retention. Findings will serve as a guiding framework when designing trials to limit barriers and enhance enablers of retention within clinical trials.
Subject(s)
Attitude to Health , Clinical Trials as Topic/statistics & numerical data , Research Subjects/statistics & numerical data , Humans , Pragmatic Clinical Trials as Topic/statistics & numerical dataABSTRACT
OBJECTIVES: To assess gout and asymptomatic hyperuricemia in Japan and review treatment conditions. METHODS: This retrospective cross-sectional study analyzed the prevalence of hyperuricemia and gout, and characteristics and treatment of patients with those conditions, using Japanese health insurance claims and medical check-up data collected from April 2016 through March 2017. RESULTS: Among 2,531,383 persons registered in the database, 1.1% (men 1.9%, women <0.1%) were diagnosed with gout and 2.6% (4.1%, 0.4%) with asymptomatic hyperuricemia. Medical check-ups showed 13.4% (19.6%, 1.0%) of patients with hyperuricemia (serum uric acid [sUA] > 7.0 mg/dL). Urate-lowering therapy (ULT) was prescribed for 80.7% of patients identified with gout and 72.4% identified with asymptomatic hyperuricemia. ULT adherence was satisfactory, but most patients were treated with low-dose ULT. Less than half of patients receiving ULT achieved the sUA target (≤6.0 mg/dL). In gout patients, the incidence of gout flare was 47.8% (0.74 flares/person-year). CONCLUSIONS: Although hyperuricemia prevalence is similar in Japan and worldwide, gout is comparatively rare in Japan. Gout and asymptomatic hyperuricemia are often treated with low-dose ULT, and many patients fail to reach target sUA, suggesting that gout management is suboptimal in Japan. Patients would benefit from stricter focus on a treat-to-target approach for gout management.
Subject(s)
Gout Suppressants/therapeutic use , Gout/drug therapy , Hyperuricemia/drug therapy , Adult , Female , Gout Suppressants/administration & dosage , Humans , Insurance, Health/statistics & numerical data , Japan , Male , Middle Aged , Pragmatic Clinical Trials as Topic/statistics & numerical dataABSTRACT
Although Evidence-based medicine (EBM) and Patient-centered medicine (PCM) are often perceived as two conflicting paradigms that speak the language of populations and the language of individuals, respectively, both share the common objective of improving the care of individual patients. As physicians should not practice an EBM that is away from the individual patient nor a PCM that is not based on the best available evidence, it is crucial to connect and combine both movements, promoting the fruitful and natural interaction between research and care. Achieving such interaction requires developing new individual-patient centric research methods. In this commentary, we propose an innovative clinical research design oriented to personalize point-of-care trials-integrating clinical research and medical care-through the incorporation of individual patients' preferences to build personalized research protocols. Building on the framework of N-of-1 studies, in "individual point-of-care trials," each protocol could be personalized for each patient so that the therapeutic objectives, the outcome variables analyzed, and the (operationalization of the) compared interventions would be based not only on the clinical and biological characteristics of each patient but also on their individual preferences, goals, and values. If patient preferences are being progressively integrated into medical practice, it makes sense that they also are incorporated into clinical trials embedded in care delivery. The proposal to perform individual point of care trials may be an optimal way to combine EBM and PCM while preserving their foundational principles, and to ensure the connection between "personalized" and "personal" care.
Subject(s)
Clinical Trials as Topic/statistics & numerical data , Clinical Trials as Topic/standards , Evidence-Based Medicine/standards , Patient Preference/statistics & numerical data , Point-of-Care Systems/standards , Pragmatic Clinical Trials as Topic/statistics & numerical data , Pragmatic Clinical Trials as Topic/standards , Adult , Aged , Aged, 80 and over , Biomedical Research/standards , Biomedical Research/statistics & numerical data , Evidence-Based Medicine/statistics & numerical data , Female , Humans , Male , Middle Aged , Point-of-Care Systems/statistics & numerical data , Practice Guidelines as Topic , Research Design/standards , Research Design/statistics & numerical dataABSTRACT
In this paper, a propensity score-integrated composite likelihood (PSCL) approach is developed for cases in which the control arm of a two-arm randomized controlled trial (RCT) (treated vs control) is augmented with patients from real-world data (RWD) containing both clinical outcomes and covariates at the patient-level. RWD patients who were treated with the same therapy as the control arm of the RCT are considered for the augmentation. The PSCL approach first estimates the propensity score for every patient as the probability of the patient being in the RCT rather than the RWD, and then stratifies all patients into strata based on the estimated propensity scores. Within each propensity score stratum, a composite likelihood function is specified and utilized to down-weight the information contributed by the RWD source. Estimates of the stratum-specific parameters are obtained by maximizing the composite likelihood function. These stratum-specific estimates are then combined to obtain an overall population-level estimate of the parameter of interest. The performance of the proposed approach is evaluated via a simulation study. A hypothetical two-arm RCT and a hypothetical RWD source are used to illustrate the implementation of the proposed approach.
Subject(s)
Computer Simulation/statistics & numerical data , Pragmatic Clinical Trials as Topic/statistics & numerical data , Propensity Score , Randomized Controlled Trials as Topic/statistics & numerical data , Registries/statistics & numerical data , Heart Failure/epidemiology , Heart Failure/therapy , Humans , Likelihood Functions , Pragmatic Clinical Trials as Topic/methods , Randomized Controlled Trials as Topic/methodsABSTRACT
Ixazomib, the first oral proteasome inhibitor (PI), has been approved for the treatment of relapsed refractory multiple myeloma (RRMM) in combination with lenalidomide and dexamethasone, based on the TOURMALINE-MM1 phase 3 trial, which demonstrated the efficacy and safety of this all-oral triplet, compared with lenalidomide-dexamethasone. However, clinical trial outcomes do not always translate into real-world outcomes. The aim of this study was to assess the outcomes of ixazomib-based combination for treatment of patients with RRMM in a real-world setting. All consecutive RRMM patients who received at least one cycle of ixazomib-based treatment combination between June 2013 and June 2018 were identified. Data was extracted from medical charts focusing on demographics, disease characteristics, prior treatment, and responses. Primary endpoint was progression-free survival (PFS); secondary endpoints included overall response rate (ORR), overall survival (OS), safety, and tolerability. A total of 78 patients across 7 sites were retrospectively included. Median follow-up was 22 months. Median age was 68 (range 38-90). Sixty-four percent received ixazomib in 2nd line, 19% in 3rd line. Overall, 89% of patients had been exposed to PIs (bortezomib 87%) prior to IRd, 41% to IMiDs. Twenty-nine (48%, of 60 available) had high (t(4:14), t(14:16), del17p) or intermediate (+1q21) risk aberrations. Most patients (82%) received ixazomib in combination with lenalidomide and dexamethasone. An exploratory assessment for disease aggressiveness at diagnosis was classified by a treating physician as indolent (rapid control to protect from target organ damage not required) vs aggressive (imminent target organ damage) in 63% vs 37%, respectively. Treatment was well tolerated, with a low discontinuation rate (11%). Median PFS on ixazomib therapy was 24 months (95% CI 17-30). PFS was 77% and 47% at 12 and 24 months, respectively. Median OS was not reached; OS was 91% and 80% at 12 and 24 months, respectively. Higher LDH, older age, and worse clinical aggressiveness were associated with worse PFS, whereas a deeper response to ixazomib (≥ VGPR) and a longer response to first-line bortezomib (≥ 24 m) were associated with an improved PFS on ixazomib. No effect on PFS was found for cytogenetic risk by FISH, ISS/rISS, and prior anti-myeloma treatment. Ixazomib-based combinations are efficacious and safe regimens in RRMM patients in the real-world setting, regardless to cytogenetic risk, with a PFS of 24 months comparable with clinical trial data. This regimen had most favorable outcomes among patients who remained progression-free more than 24 months after a bortezomib induction and for those who have a more indolent disease phenotype.
Subject(s)
Antineoplastic Agents/administration & dosage , Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Boron Compounds/administration & dosage , Glycine/analogs & derivatives , Multiple Myeloma/drug therapy , Pragmatic Clinical Trials as Topic/methods , Registries , Adult , Aged , Aged, 80 and over , Data Analysis , Female , Follow-Up Studies , Glycine/administration & dosage , Humans , Israel/epidemiology , Male , Middle Aged , Multiple Myeloma/diagnosis , Multiple Myeloma/epidemiology , Pragmatic Clinical Trials as Topic/statistics & numerical data , Recurrence , Treatment OutcomeABSTRACT
One of the most challenges for rare diseases drug development is probably the availability of subjects with the diseases under a small patient population. It is then a great concern how to conduct clinical trials with the limited number of subjects available for obtaining substantial evidence regarding effectiveness and safety for approval of the drug product under investigation. For rare diseases drug development, FDA indicated that the Agency does not have the intention to create a statutory standard for approval of orphan drugs that is different from the standard for approval of drugs in common conditions. In this case, innovative thinking and approach for obtaining substantial evidence for approval of rare diseases drug products are necessarily applied. In this article, basic considerations for rare disease drug development are discussed. The innovative thinking of demonstrating not-ineffectiveness rather than effectiveness with a limited number of subjects available is outlined. In addition, an innovative approach utilizing a two-stage adaptive seamless trial design in conjunction with the concept of real-world data and real-world evidence is proposed not only to obtain substantial evidence for approval of rare diseases drug products, but also to meet the same standard as those drug products in common conditions. Under the two-stage adaptive seamless trial design, sample size calculation for rare diseases clinical trials based on the innovative probability monitoring procedure is also discussed.
Subject(s)
Drug Approval/statistics & numerical data , Drug Development/statistics & numerical data , Orphan Drug Production/statistics & numerical data , Rare Diseases/drug therapy , Research Design/statistics & numerical data , United States Food and Drug Administration/statistics & numerical data , Clinical Trials as Topic/methods , Clinical Trials as Topic/statistics & numerical data , Drug Approval/methods , Drug Development/methods , Humans , Orphan Drug Production/methods , Pragmatic Clinical Trials as Topic/methods , Pragmatic Clinical Trials as Topic/statistics & numerical data , Rare Diseases/epidemiology , United StatesABSTRACT
OBJECTIVE: To determine the proportion of Phase III clinical trials given a favourable opinion by a research ethics committee in the UK that provided trial results to those who participated. DESIGN: Audit of records. SETTING: Phase III clinical trials registered on the UK's research permissions system (Integrated Research Application System) between the 1 January 2012 to 31 December 2017. MAIN OUTCOME MEASURES: Proportion of trial investigators that intended to provide results to trial participants compared against what trials reported to ethics committees at the end of study. RESULTS: Out of 1404 Phase III trials, 87.7% (n=1231) trials stated they intended to disseminate results to participants while 12.3% (n=173) trials stated they would not. Out of these 1231 trials, 18.8% (n=231) trials intended to actively communicate trial results or a means of accessing results to their participants, a further 80.5% (n=991) reported passive intention to disseminate and for the remainder (n=9) the process was unclear. Of the 370 End of Study reports (30% of all included studies) that could be accessed 10 (2.7%) explicitly mentioned activities related to dissemination of findings to participants with the majority (74.9%) having no mention and a further 22.4% of reports not being accessible. Of the 10 which did report dissemination of results to participants the majority (n=6) were through a lay summary or letter. CONCLUSIONS: Reported intention to disseminate results to trial participants among trial investigators is high, however, reporting of feedback methods is lacking. In addition, mechanisms to ensure intentions to disseminate trial results are translated into actual behaviour need to be put in place to ensure those who participate in trials have the opportunity to find out about the results.
Subject(s)
Clinical Audit , Clinical Trials, Phase III as Topic/statistics & numerical data , Information Dissemination/methods , Pragmatic Clinical Trials as Topic/statistics & numerical data , Randomized Controlled Trials as Topic/statistics & numerical data , Humans , United KingdomABSTRACT
Real-world data and patient-level data from completed randomized controlled trials are becoming available for secondary analysis on an unprecedented scale. A range of novel methodologies and study designs have been proposed for their analysis or combination. However, to make novel analytical methods acceptable for regulators and other decision makers will require their testing and validation in broadly the same way one would evaluate a new drug: prospectively, well-controlled, and according to a pre-agreed plan. From a European regulators' perspective, the established methods qualification advice procedure with active participation of patient groups and other decision makers is an efficient and transparent platform for the development and validation of novel study designs.
Subject(s)
Data Collection/standards , Decision Making , Pragmatic Clinical Trials as Topic/standards , Randomized Controlled Trials as Topic/standards , Data Collection/methods , Humans , Pragmatic Clinical Trials as Topic/methods , Pragmatic Clinical Trials as Topic/statistics & numerical data , Prospective Studies , Randomized Controlled Trials as Topic/methods , Randomized Controlled Trials as Topic/statistics & numerical data , Reproducibility of ResultsABSTRACT
AIM: To be in accord with the Consolidated Standards of Reporting Trials (CONSORT) Statement, all important adverse events in randomised controlled trials (RCTs) should be reported, as well as trial registration. Neither concern has been investigated in venous leg ulcer trials. We therefore aimed to quantify and explore compliance with adverse event reporting and trials registration in RCTs that reported interventions for treating venous leg ulceration. MATERIALS AND METHODS: We searched the Cochrane Controlled Trials Register, Medline, Embase, and CINAHL for studies reported between 2001 and 2017. Included studies must have been described as randomised controlled trials evaluating any intervention in a VLU population. Data was then extracted by one author into a standard form and checked by a second author. RESULTS: We screened 3100 titles and identified 204 trials involving pharmaceuticals (82), medicated and non-medicated devices (102), organisational (5) or other interventions (15) published in 76 journals. Eighty-four trials reported adverse events (41.2%), while 18 reported no events occurred (8.8%) and 78 did not report adverse events (38.2%). Types of adverse events reported included all-cause (20.1%), ulcer-related only (38.2%), treatment-related only (11.3%) and serious adverse events only (1.0%). Only 38 trials were registered (18.6%). Trial registration was associated with reporting of any adverse events (Odds Ratio 3.0, 95%CI 1.1-7.9), as was the trial being a pharmaceutical trial (Odds Ratio 2.9, 95%CI 1.5-5.7) or a multicentre trial (Odds Ratio 4.2, 95%CI 2.2-8.1). CONCLUSION: Adverse event reporting in VLU trials is variable with about one third of trials not reporting on adverse events at all. Trials registration is a the modifiable factor associated with better reporting of adverse events. Journal editors could explore how they can promote trials registration to enhance better reporting of harms in VLU trials.
Subject(s)
Pragmatic Clinical Trials as Topic/statistics & numerical data , Pressure Ulcer/therapy , Risk Management/methods , Humans , Risk Management/standardsABSTRACT
In medical product development, there has been an increased interest in utilizing real-world data which have become abundant with recent advances in biomedical science, information technology, and engineering. High-quality real-world data may be analyzed to generate real-world evidence that can be utilized in the regulatory and healthcare decision-making. In this paper, we consider the case in which a single-arm clinical study, viewed as the primary data source, is supplemented with patients from a real-world data source containing both clinical outcome and covariate data at the patient-level. Propensity score methodology is used to identify real-world data patients that are similar to those in the single-arm study in terms of the baseline characteristics, and to stratify these patients into strata based on the proximity of the propensity scores. In each stratum, a composite likelihood function of a parameter of interest is constructed by down-weighting the information from the real-world data source, and an estimate of the stratum-specific parameter is obtained by maximizing the composite likelihood function. These stratum-specific estimates are then combined to obtain an overall population-level estimate of the parameter of interest. The performance of the proposed approach is evaluated via a simulation study. A hypothetical example based on our experience is provided to illustrate the implementation of the proposed approach.
Subject(s)
Computer Simulation/statistics & numerical data , Data Interpretation, Statistical , Pragmatic Clinical Trials as Topic/statistics & numerical data , Propensity Score , Humans , Likelihood Functions , Pragmatic Clinical Trials as Topic/methodsSubject(s)
Informed Consent , Pragmatic Clinical Trials as Topic/methods , Uncertainty , Humans , Observational Studies as Topic/methods , Pragmatic Clinical Trials as Topic/classification , Pragmatic Clinical Trials as Topic/statistics & numerical data , Prospective Studies , Random Allocation , Risk AssessmentABSTRACT
We are now at an amazing time for medical product development in drugs, biological products and medical devices. As a result of dramatic recent advances in biomedical science, information technology and engineering, ``big data'' from health care in the real-world have become available. Although big data may not necessarily be attuned to provide the preponderance of evidence to a clinical study, high-quality real-world data can be transformed into scientific evidence for regulatory and healthcare decision-making using proven analytical methods and techniques, such as propensity score methodology and Bayesian inference. In this paper, we extend the Bayesian power prior approach for a single-arm study (the current study) to leverage external real-world data. We use propensity score methodology to pre-select a subset of real-world data containing patients that are similar to those in the current study in terms of covariates, and to stratify the selected patients together with those in the current study into more homogeneous strata. The power prior approach is then applied in each stratum to obtain stratum-specific posterior distributions, which are combined to complete the Bayesian inference for the parameters of interest. We evaluate the performance of the proposed method as compared to that of the ordinary power prior approach by simulation and illustrate its implementation using a hypothetical example, based on our regulatory review experience.
Subject(s)
Biological Products , Pragmatic Clinical Trials as Topic/methods , Pragmatic Clinical Trials as Topic/statistics & numerical data , Propensity Score , Bayes Theorem , Biological Products/chemistry , Biological Products/therapeutic use , HumansABSTRACT
BACKGROUND: The paper opens with a brief history of two of the major intellectual components of the recent utilitarian turn in clinical research, namely 'pragmatic trials' and 'implementation science'. The two schools of thought developed independently and the paper scrutinises their mutual compatibilities and incompatibilities, asking: i) what do the leading advocates of pragmatic trials assume about the transfer of research findings to real-world practice and ii) what role pragmatic trials can and should play in the evaluation of implementation science strategies. METHODS: The paper utilises 'explication de texte': i) providing a close reading of the inferential logics contained in major published expositions of the two paradigms, and ii) interrogating the conclusions of a pragmatic trial of an intervention providing guidelines on retinal screening aimed at family practitioners. RESULTS: The paper is in two parts. Part 1 unearths some significant incommensurability - the pragmatic trial literature retains an antiquated view of knowledge transfer and is overly optimistic about the wide applicability the findings of pragmatic trials to 'real world' conditions. Part 2 of the paper outlines an empirical strategy to better penetrate the mechanisms of knowledge transfer and to tackle the issue of the generalisabilty of research findings in implementation science. CONCLUSIONS: Pragmatism, classically, is about problem solving and the melding of perspectives. The core research requirement in implementation science is a fundamental shift from the narrow shoulders of pragmatic trials to a model of explanation building based upon a multi-case, multi-method body of evidence.
Subject(s)
Biomedical Research/methods , Evidence-Based Practice/methods , Implementation Science , Pragmatic Clinical Trials as Topic/methods , Research Design , Biomedical Research/standards , Biomedical Research/statistics & numerical data , Evidence-Based Practice/standards , Evidence-Based Practice/statistics & numerical data , Humans , Pragmatic Clinical Trials as Topic/standards , Pragmatic Clinical Trials as Topic/statistics & numerical data , Reproducibility of ResultsABSTRACT
OBJECTIVES: European regulations do not allow modification or waiver of informed consent for medicines randomized controlled trials (RCTs) where the three 2016 Council for International Organizations of Medical Sciences (CIOMS) provisions are met (consent would be impractical or unfeasible, yet the trial would have high social value and pose no or minimal risk to participants). We aimed to identify whether any such trials of medicines were being conducted in Europe. STUDY DESIGN AND SETTING: This is a survey of all phase 4 "ongoing" RCTs on the EU clinical trial register between July 1, 2016 and June 30, 2018, to identify those with potentially high levels of pragmatism. Trials that were excluded were as follows: those conducted on rare diseases; conducted on healthy volunteers (except those assessing vaccines); masked (single-, double-blind) trials; single-center trials; those where one could expect to lead patients to prefer one intervention over the other; and miscellaneous reasons. The degree of pragmatism of the RCTs was self-assessed by trials' investigators by means of the PRECIS-2 tool. Investigators of those trials considered to be highly pragmatic assessed the fulfillment of the three CIOMS provisions. Seven patients assessed the social value of the RCTs. Finally, 33 members of 11 research ethics committees (RECs) assessed the social value of the trials and whether they posed no more than minimal risk to participants. Investigators, patients, and REC members assessed the fulfillment of the CIOMS provisions as "yes," "not sure" or "no." RESULTS: Of the 638 phase 4 trials, 420 were RCTs, and 21 of these (5%) were candidates to be pragmatic. Investigators of 15 of these 21 RCTs self-assessed their trial's degree of pragmatism: 14 were highly pragmatic. Of these 14, eight fulfilled the three CIOMS provisions. Assessments by patients and RECs were inconsistent for several trials. CONCLUSIONS: We found few low-risk participant-level pragmatic RCTs that could be suitable for modified or waived participants' informed consent. European regulators should consider amending the current regulation and encouraging the conduct of such trials.
Subject(s)
Clinical Trials, Phase IV as Topic/statistics & numerical data , Informed Consent , Pragmatic Clinical Trials as Topic/statistics & numerical data , Clinical Trials, Phase IV as Topic/legislation & jurisprudence , Europe , Government Regulation , Humans , Informed Consent/legislation & jurisprudence , Patient Selection , Pragmatic Clinical Trials as Topic/legislation & jurisprudence , Randomized Controlled Trials as Topic/legislation & jurisprudence , Randomized Controlled Trials as Topic/statistics & numerical data , Risk AssessmentABSTRACT
Stratified cluster randomization trials (CRTs) have been frequently employed in clinical and healthcare research. Comparing with simple randomized CRTs, stratified CRTs reduce the imbalance of baseline prognostic factors among different intervention groups. Due to the popularity, there has been a growing interest in methodological development on sample size estimation and power analysis for stratified CRTs; however, existing work mostly assumes equal cluster size within each stratum and uses multilevel models. Clusters are often naturally formed with random sizes in CRTs. With varying cluster size, commonly used ad hoc approaches ignore the variability in cluster size, which may underestimate (overestimate) the required number of clusters for each group per stratum and lead to underpowered (overpowered) clinical trials. We propose closed-form sample size formulas for estimating the required total number of subjects and for estimating the number of clusters for each group per stratum, based on Cochran-Mantel-Haenszel statistic for stratified cluster randomization design with binary outcomes, accounting for both clustering and varying cluster size. We investigate the impact of various design parameters on the relative change in the required number of clusters for each group per stratum due to varying cluster size. Simulation studies are conducted to evaluate the finite-sample performance of the proposed sample size method. A real application example of a pragmatic stratified CRT of a triad of chronic kidney disease, diabetes, and hypertension is presented for illustration.
Subject(s)
Randomized Controlled Trials as Topic/statistics & numerical data , Biostatistics , Clinical Protocols , Cluster Analysis , Computer Simulation , Diabetic Angiopathies/complications , Diabetic Angiopathies/therapy , Diabetic Nephropathies/complications , Diabetic Nephropathies/therapy , Humans , Hypertension/complications , Hypertension/therapy , Outcome Assessment, Health Care/statistics & numerical data , Pragmatic Clinical Trials as Topic/statistics & numerical data , Random Allocation , Renal Insufficiency, Chronic/complications , Renal Insufficiency, Chronic/therapy , Sample SizeABSTRACT
AIMS: The study aims to examine how therapists trained in motivational interviewing (MI) respond to resistance and whether this has an impact on subsequent client speech. METHODS: Fifty recorded Motivational Enhancement Therapy sessions were examined using a sequential behavioural coding method for speech. Client counter-change talk formed the baseline for coding and categorizing subsequent therapist speech and the following client speech. Transitional analysis identified the probable occurrence of specific therapist and client utterances at each stage. RESULTS: Following client expressed resistance or counter-change talk, MI consistent therapist utterances were most commonly observed. A moderate to strong predictive relationship was found between MI-consistent therapist speech and subsequent client change talk. A moderate predictive relationship was found between therapist MI-consistent behaviours and client ambivalence. A moderate to strong predictive relationship was found between MI-inconsistent therapist speech and subsequent client counter-change talk and a weak negative predictive relationship was found between MI-inconsistent therapist speech and client expressed ambivalence. CONCLUSIONS: In the face of initial expressed resistance to change, MI-consistent therapist speech appears to increase subsequent client utterances regarding intentions to change drinking behaviour.
Subject(s)
Alcohol Drinking/therapy , Motivational Interviewing/statistics & numerical data , Pragmatic Clinical Trials as Topic/statistics & numerical data , Professional-Patient Relations , Speech , Humans , MotivationABSTRACT
BACKGROUND: We use the example of the Gojjam Lymphoedema Best Practice Trial (GoLBeT), a pragmatic trial in a remote rural setting in northern Ethiopia, to extract lessons relevant to other investigators balancing the demands of practicality and community acceptability with internal and external validity in clinical trials. METHODS: We explain in detail the preparation for the trial, its setting in northern Ethiopia, the identification and selection of patients (inclusion and exclusion criterion, identifying and screening of patients at home, enrollment of patients at the health centres and health posts), and randomisation. RESULTS: We describe the challenges met, together with strategies employed to overcome them. CONCLUSIONS: Examples given in the previous section are contextualised and general principles extracted where possible. We conclude that it is possible to conduct a trial that balances approaches that support internal validity (e.g. careful design of proformas, accurate case identification, control over data quality and high retention rates) with those that favour generalisability (e.g. 'real world' setting and low rates of exclusion). Strategies, such as Rapid Ethical Assessment, that increase researchers' understanding of the study setting and inclusion of hard-to-reach participants are likely to have resource and time implications, but are vital in achieving an appropriate balance. TRIAL REGISTRATION: ISRCTN67805210, registered 24/01/2013.