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PubMed1985

Termination of clinical trials: the beta-blocker heart attack trial and the hypertension detection and follow-up program experience.

The close-out of clinical trials that end ahead of schedule often involves problems that differ from those of trials that end as planned. The Beta-Blocker Heart Attack Trial (BHAT), a double-blind study of 3837 post-myocardial infarction patients, was a multicenter clinical trial that ended early because therapeutic benefit had been demonstrated. The Hypertension Detection and Follow-up Program (HDFP), a randomized unblinded study of 10,940 hypertensive individuals, was a multicenter trial that ended as planned. Using these trials as illustrations, the issues arising in multicenter trials that end ahead of schedule are contrasted to those that arise in trials that end as scheduled. Close-out activities that are discussed include documentation of close-out procedures, release of trial information, preparation of trial participants and staff, ascertaining vital status, continuing patient care, data collection and coding, and publication of trial results. Because of the possibility a study might end early, advance planning for close-out is essential.

Adult↗
PubMed2005

Predicting the outcome of phase III trials using phase II data: a case study of clinical trial simulation in late stage drug development.

Maximizing the likelihood of success in Phase III is the ultimate goal of the use of modelling and simulation in the drug development process. The success in Phase III depends primarily on two questions: 1) Is the drug regimen actually efficacious and safe in the targeted patient population?, and 2) Will the planned Phase III clinical trial(s) be successful in demonstrating this? Traditionally, the first question is addressed in a qualitative, overall interpretation of available study results. Integrating this information into a formal statistical model of the action of the drug, allows running simulations to investigate the impact of uncertainties and imprecision in this knowledge. The second question is related to having an adequately designed clinical trial. Clinical trial simulation, using a drug action model, supplemented with appropriate models for disease progression and trial execution, allows assessing the impact of typical design features such as doses, sample size, in-/exclusion criteria, drop-out and trial duration on the trial outcome and thus optimising trial design. In this contribution, the use of modelling and simulation in the Phase II to Phase III transition is illustrated using real data of a drug for symptom relief in a chronic condition. A dose-response model of the clinical response was developed using data from Phase II. Simulations were performed to 1) generate the range of possible outcomes of ongoing Phase III trials and compare these to the blinded data being generated from these trials; 2) assess the robustness of the ongoing Phase III trials with respect to uncertainty of the true dose-response, patient variability in baseline severity and drug-response, and 3) assess the likelihood of achieving a clinically relevant response with a dose lower than those included in the trials.

Clinical Trials, Phase II as Topic↗
PubMed2006

Guidelines for the conduct of clinical trials for spinal cord injury as developed by the ICCP panel: spontaneous recovery after spinal cord injury and statistical power needed for therapeutic clinical trials.

The International Campaign for Cures of Spinal Cord Injury Paralysis (ICCP) supported an international panel tasked with reviewing the methodology for clinical trials in spinal cord injury (SCI), and making recommendations on the conduct of future trials. This is the first of four papers. Here, we examine the spontaneous rate of recovery after SCI and resulting consequences for achieving statistically significant results in clinical trials. We have reanalysed data from the Sygen trial to provide some of this information. Almost all people living with SCI show some recovery of motor function below the initial spinal injury level. While the spontaneous recovery of motor function in patients with motor-complete SCI is fairly limited and predictable, recovery in incomplete SCI patients (American spinal injury Association impairment scale (AIS) C and AIS D) is both more substantial and highly variable. With motor complete lesions (AIS A/AIS B) the majority of functional return is within the zone of partial preservation, and may be sufficient to reclassify the injury level to a lower spinal level. The vast majority of recovery occurs in the first 3 months, but a small amount can persist for up to 18 months or longer. Some sensory recovery occurs after SCI, on roughly the same time course as motor recovery. Based on previous data of the magnitude of spontaneous recovery after SCI, as measured by changes in ASIA motor scores, power calculations suggest that the number of subjects required to achieve a significant result from a trial declines considerably as the start of the study is delayed after SCI. Trials of treatments that are most efficacious when given soon after injury will therefore, require larger patient numbers than trials of treatments that are effective at later time points. As AIS B patients show greater spontaneous recovery than AIS A patients, the number of AIS A patients requiring to be enrolled into a trial is lower. This factor will have to be balanced against the possibility that some treatments will be more effective in incomplete patients. Trials involving motor incomplete SCI patients, or trials where an accurate assessment of AIS grade cannot be made before the start of the trial, will require large subject numbers and/or better objective assessment methods.

Clinical Trials as Topic↗
PubMed2006

Guidelines for the conduct of clinical trials for spinal cord injury as developed by the ICCP panel: clinical trial design.

The International Campaign for Cures of Spinal Cord Injury Paralysis established a panel tasked with reviewing the methodology for clinical trials for spinal cord injury (SCI), and making recommendations on the conduct of future trials. This is the fourth of four papers. Here, we examine the phases of a clinical trial program, the elements, types, and protocols for valid clinical trial design. The most rigorous and valid SCI clinical trial would be a prospective double-blind randomized control trial utilizing appropriate placebo control subjects. However, in specific situations, it is recognized that other trial procedures may have to be considered. We review the strengths and limitations of the various types of clinical trials with specific reference to SCI. It is imperative that the design and conduct of SCI clinical trials should meet appropriate standards of scientific inquiry to insure that meaningful conclusions about efficacy and safety can be achieved and that the interests of trial subjects are protected. We propose these clinical trials guidelines for use by the SCI clinical research community.

Clinical Trials as Topic↗
PubMed2006

Sequential meta-analysis of past clinical trials to determine the use of a new trial.

BACKGROUND: Clinical trials can be stopped early based on interim analyses or sequential analyses. In principle, sequential analyses can also be used to decide whether enough evidence has been gathered in completed trials to make further trials unnecessary. We demonstrate such an application through a retrospective analysis of clinical trials comparing ventilation methods for the treatment of preterm newborns. METHODS: We identified 5 recent trials that compared high-frequency ventilation with conventional mechanical ventilation in the treatment of preterm newborns. Death or chronic lung disease and chronic lung disease in survivors were the primary clinical outcomes of interest. We applied sequential meta-analyses to these 5 studies. RESULTS: After including the first study of the last 5 trials in a sequential meta-analysis, the boundary of "no clinically relevant effect" was crossed for both outcomes (death or chronic lung disease). A sensitivity analysis using a reduction in the size of assumed clinically relevant effect showed the same findings after 2 trials. CONCLUSIONS: Sequential meta-analyses showed that a lack of clinically relevant effect had been established after the first of the 5 trials. If such an analysis had been conducted after the first or second of these clinical trials, it might have led to changes in the study design of subsequent trials or even to a reassessment of the need for further trials.

High-Frequency Ventilation↗
PubMedDate not supplied

Key methodological features of randomized controlled trials of Alzheimer's disease therapy. Minimal clinically important difference, sample size and trial duration.

BACKGROUND: The results of clinical trials are routinely presented in terms of statistical significance, which may or may not indicate clinical significance. Analysis of the minimal clinically important difference (MCID) of cognitive scales has received little attention to date. OBJECTIVES: By reviewing the key methodological features (sample size, duration, statistical and clinical significance) of clinical trials examining the efficacy of tacrine in the treatment of Alzheimer's disease (AD), we assessed their ability to detect clinically important changes in cognition. DESIGN: The value for the MCID of the Mini-Mental State Examination (MMSE) was determined by surveying specialists in neurology and geriatric medicine. This value was then used to interpret the clinical significance of the results of published randomized controlled trials (RCTs) assessing the efficacy of tacrine in the treatment of AD and to retrospectively determine their optimal sample size and trial duration. RESULTS: The mean survey MCID for the MMSE was 3.72 (95% confidence interval 3.50-3.95) points. Only 2 of 12 tacrine RCTs using the MMSE found a statistically significant difference in MMSE scores for patients taking tacrine compared with those taking placebo. These improvements were not clinically significant when compared with the survey MMSE MCID. For parallel trials of tacrine in AD, the smallest sample size and minimum trial duration required to demonstrate a clinically significant difference were calculated to be 53 subjects and 1 year, respectively. Five of the 7 parallel trials met the required sample size; however, none of them met the criteria for trial duration. CONCLUSIONS: When using the MMSE as an outcome measure, no tacrine trial reported results that were clinically significant as perceived by clinicians working with dementia patients. Application of a range of plausible MCIDs to the parallel design RCTs also demonstrated that 2 of 7 of these trials did not have sufficient sample size, and none had sufficient duration of treatment to reliably detect clinically meaningful changes in cognition. Future clinical trials in this area will need to incorporate the evolving knowledge of MCIDs in order to increase their chance of detecting clinically relevant results. CopyrightCopyright 1999S.KargerAG,Basel

Aged↗
PubMed2001

Concentration-controlled or effect-controlled trials: useful alternatives to conventional dose-controlled trials?

Historically, dose-finding trials have been confirmatory in nature despite the fact that these trials represent an important and essential 'learning' phase in the drug development process. About 10 years ago 2 alternatives to the randomised dose-controlled trial (RDCT) were proposed as being more informative trial types. Controlling systemic drug exposure in order to improve efficiency of a trial forms the basis for the suggestion of a randomised concentration-controlled trial (RCCT). For the common instance where pharmacodynamic variability is larger than pharmacokinetic variability, the randomised effect-controlled trial (RECT), where patients are randomised to the effect of interest was suggested as even more informative. A survey of the literature shows that the RCCT has been sparsely applied and RECT not at all. For RCCT, the practical complications of carrying out the study seldom makes it the study type of choice. For RECT, the limited number of suitable situations for its application and the fact that the same effect is used for randomisation and analysis may explain the lack of applications. As a somewhat more favourable trial type, we suggest the randomised biomarker-controlled trial (RBCT), where patients are randomised to a certain value or range of a biomarker whereas the analysis is performed on another, clinically more relevant, effect. Although the RBCT has some attractive features, for example contributing to validation of a biomarker as a surrogate for clinical outcome, it is unlikely to be extensively used. Instead, the main shift from confirming to learning in dose-finding trials is coming from the incorporation of well-known learning components into the RDCT (e.g. sparse concentration measurements combined with population pharmacokinetic-pharmacodynamic, biomarker measurements and analysis of effect measures throughout the entire trial period).

Dose-Response Relationship, Drug↗
PubMedDate not supplied

Safety outcomes in meta-analyses of phase 2 vs phase 3 randomized trials: Intracranial hemorrhage in trials of bolus thrombolytic therapy.

CONTEXT: Recent studies have reported disagreement between meta-analysis of small trials and subsequent large trials addressing the same question. However, disagreement for uncommon but serious adverse safety outcomes has not been examined. OBJECTIVE: To explore disagreement for serious adverse safety (intracranial hemorrhage [ICH]) and efficacy outcomes between meta-analysis of phase 2 (small) vs meta-analysis of phase 3 (large) randomized controlled trials comparing the efficacy of bolus thrombolytic therapy with infusion for acute myocardial infarction (AMI). DATA SOURCES: Electronic databases (MEDLINE, Cochrane Database of Clinical Trials) between January 1980 and December 1999 using the search terms thrombolysis, thrombolytic therapy, and myocardial infarction; conference proceedings; and reference lists. STUDY SELECTION: Fifteen randomized trials comparing thrombolytic agents administered by bolus injection with standard infusion therapy in patients with AMI. DATA EXTRACTION: Data on ICH, other causes of stroke, total mortality, and reinfarction were independently extracted from each study by 2 observers. DATA SYNTHESIS: Meta-analysis of 9 phase 2 trials (n = 3956) revealed a lower risk of ICH with bolus thrombolytic therapy (odds ratio [OR], 0.53; 95% confidence interval [CI], 0.27-1.01), which was not statistically significant. Meta-analysis of 6 phase 3 trials (n = 62 673) indicated a significant increase in risk of ICH (OR, 1.25; 95% CI, 1.06-1.49). These results were significantly different (P =.01). There was no disagreement for efficacy outcomes. Phase 2 trials included younger and heavier patients with lower baseline blood pressures, and were more often open-label. Subgroup analyses suggested that each of these factors was associated with a lower estimate of risk of ICH with bolus agents. CONCLUSIONS: Our results suggest that when therapeutic interventions are associated with a potential for uncommon but serious adverse safety outcomes, there may be differences between small phase 2 and large phase 3 trials that result in their disagreement for safety but not necessarily efficacy outcomes. Further investigation of the frequency and causes of disagreement between small and large trials for safety outcomes is warranted.

Clinical Trials, Phase II as Topic↗
PubMed2005

Orthodontic Clinical Trials III: reporting of ethical issues associated with clinical trials published in three orthodontic journals between 1989 and 1998.

AIMS: The aims of this study were to assess whether reports of orthodontic clinical trials complied with the requirements of the Declaration of Helsinki. DESIGN: A retrospective observational study. SETTING: The American Journal of Orthodontics and Dentofacial Orthopedics (AJODO), Journal of Orthodontics (formerly and up until 1999 known as the British Journal of Orthodontics, BJO) and European Journal of Orthodontics (EJO). DATA SOURCE: Clinical trials published between 1989 and 1998. METHODS: A hand search was performed to identify all clinical trials. Each trial report was assessed for inclusion of a statement that ethical approval and/or informed consent had been obtained. RESULTS: One-hundred-and-fifty-five papers were identified, of which 85 (54.8%) were reports of randomized controlled trials (RCTs) and 70 (45.2%) of controlled clinical trials (CCTs). 16.1% (25/155), of the trial reports stated that ethical approval had been obtained and a quarter (39/155, 25.1%) indicated that informed consent had been obtained. CONCLUSIONS: Most orthodontic clinical trial reports failed to state whether ethical approval and/or informed consent had been obtained. The reporting of the ethical issues associated with orthodontic clinical trials could be improved further not only by the instructions to authors in orthodontic journals stating the need for studies to comply with the Declaration of Helsinki, but also by Journal editors refusing to publish trials that do not comply.

Clinical Trials as Topic↗
PubMed2026

Timing of OMERACT core domain measurement in gout clinical trials: a systematic review of randomised trials.

AIMS: The Outcome Measures in Rheumatology (OMERACT) initiative has endorsed core domain sets for gout trials. The aims of this study were to evaluate the time points and frequencies at which the gout core domains are measured in existing gout urate-lowering therapy and gout flare trials, and whether all collected measurements were reported. METHODS: Urate-lowering therapy (n = 29) and gout flare randomised clinical trials (n = 14) from 2005 were identified from a prior systematic review of core domain reporting. Data were extracted for the time points and frequencies at which each core domain was measured, as well as whether all collected measurements were reported. RESULTS: In urate-lowering therapy trials, the core domains were measured at seven different frequencies. Serum urate and gout flares were most commonly measured monthly, and tophus burden was most commonly measured three monthly. Reporting of all collected measurements varied, from 24/29 (83%) trials for serum urate to 0/2 (0%) trials for activity limitation. In gout flare trials, core domains were measured at nine different frequencies. Pain, joint tenderness and joint swelling were most commonly measured monthly. Reporting of all collected measurements varied, from 13/14 (93%) trials for pain to 3/8 (37.5%) trials for joint tenderness. CONCLUSION: In both urate-lowering therapy and gout flare trials, there is substantial variability in when the core domains are measured, and reporting of collected measurements is inconsistent. This work provides the foundation for a consensus process to establish standardised time points and frequencies for measuring the OMERACT-endorsed gout core domains.

Gout↗
PubMed2003

Clinical trials in orthodontics I: demographic details of clinical trials published in three orthodontic journals between 1989 and 1998.

AIM: To test the hypothesis that there is insufficient evidence available, from clinical trials, to allow evidence-based decisions to be made on the effectiveness of orthodontic treatment. OBJECTIVES: To identify reports of orthodontic clinical trials and assess their demographic characteristics. DESIGN: A retrospective, observational study. SETTING: The American Journal of Orthodontics and Dentofacial Orthopedics, British Journal of Orthodontics, and European Journal Orthodontics. DATA SOURCE: Clinical trials published between 1989 and 1998. METHOD: A hand-search was performed to identify all clinical trials. The journal and year of publication, research method, interventions, and sample size of the trials reported were recorded. RESULTS: One-hundred-and-fifty-five trial reports were identified of which 56 (36.1%) were published from 1989 to 1993 and 99 (69%) from 1994 to 1998. Ninety-nine (69%) reports were published in the AJO-DO, 18 (11.6%) in the BJO and 38 (24.5%) in the EJO. Eighty-five (54.8%) were reports of randomized controlled trials and 70 (45.2%) of controlled clinical trials. The interventions most frequently assessed were bonding materials (21.9%), growth modification treatments (21.3%), and oral hygiene procedures (9.0%). The median sample size was 32 (IQR 19.5, 50). CONCLUSION: There is sufficient evidence available from clinical trials to warrant doing systematic reviews of orthodontic clinical trials to aid decision-making.

Controlled Clinical Trials as Topic↗
PubMedDate not supplied

Dextroamphetamine pilot crossover trials and n of 1 trials in patients with chronic tension-type and migraine headache.

OBJECTIVE: To examine the preventive effects of dextroamphetamine in select small groups of patients with chronic tension-type and migraine headache. BACKGROUND: Neither amphetamine nor methylphenidate is used as a headache preventive. This study was undertaken after a chance observation led one of us to prescribe dextroamphetamine with apparent successes in specific patients with chronic tension-type or migraine headaches. METHODS: Two pilot trials were done. Trial 1 tested patients who were taking dextroamphetamine, while Trial 2 tested patients who had never taken this drug. Each trial obtained full data on eight subjects with chronic tension-type headache and eight subjects with migraine headache. A randomized, double-blinded, controlled, multiple-crossover design was used. Subjects took capsules containing dextroamphetamine or equi-stimulatory caffeine (the control) during four alternating 20-day periods. Trial 1 subjects took their pretrial dextroamphetamine dose at breakfast and lunch. Trial 2 subjects took 10 mg at these times. Subjects recorded the integer from 0 to 3 that represented their headache intensity during the previous 24 hours. The subject's data were the average daily headache grade for the two dextroamphetamine periods and for the two caffeine periods. The differential effect of amphetamine and caffeine on each group of eight subjects and on each individual was analyzed by t-tests. RESULTS: In both trials, the tension-type and migraine groups had lower mean daily headache grades in the amphetamine than in the caffeine periods. P values for these differences indicated that there were real drug effects, on the average, in the migraine groups (P<.05) and suggestive but inconclusive effects in the tension-type groups (P<.10). The individual n of 1 analyses showed that five tension-type and three migraine subjects in Trial 1 and three tension-type and three migraine subjects in Trial 2 had considerably lower mean daily headache grades on amphetamine with P values indicating, at various levels of significance (from P<.05 to P<.001), real amphetamine effects. Twelve of the remaining 18 patients had lower, albeit not significant, mean daily grades with amphetamine. No subject in either trial had a significantly lower mean daily headache grade on caffeine. CONCLUSIONS: Dextroamphetamine had real preventive effects on chronic tension-type and migraine headaches in some subjects. These results should encourage other investigators to study its effects on these headaches.

Adolescent↗
PubMed1991

Aspects of the science of cancer prevention trials: lessons from the conduct and planning of clinical trials of a low-fat diet intervention among women.

Cancer prevention trials are contrasted with cancer therapy trials, cardiovascular disease prevention trials, epidemiologic cohort and case-control studies, and trials with surrogate endpoints, in order to highlight some of their unique features and in order to examine the role of such trials in the cancer prevention agenda. The implication of these features and this role are discussed with respect to trial rationale, trial design, and trial protocol, with planning exercises for proposed dietary fat intervention trials among women providing illustration. Finally, some considerations are mentioned for the planning of a primary prevention trial of breast cancer using tamoxifen.

Aged↗
PubMed2000

Information presentation and decisions to enter clinical trials: a hypothetical trial of hormone replacement therapy.

We examined recruitment to an imaginary trial of hormone replacement therapy (HRT) following two different styles of information about HRT. We predicted that for treatments which, like HRT, are available outside a trial, people offered the facts as currently known would be less likely to remain unsure about the relative costs and benefits, and so less likely to agree to enter a randomised trial. In contrast, when the information provided reflected the current state of uncertainty which justified the trial, we predicted that people would be less likely to form a preference for one treatment arm over the other, and so more likely to agree to enter a trial. One hundred women aged 25-40 years were informed about HRT via a video and an information leaflet. For half the participants the information was framed in a way which emphasised the current state of uncertainty about the relative costs and benefits of HRT, and in that respect it reflected the justification for a trial. This version was considered to be similar in style to information commonly provided to potential trial participants. For half the participants the same information was framed in a way which offered explicit numerical detail about currently known facts, and in that respect it was considered to be similar in style to information commonly available to doctors prior to a trial. Women learned as much about HRT in the two conditions, but women given the explicit versions were more likely (i) to hold a stronger view about whether or not they would take HRT (ratings were not elicited from the first 30 participants in this condition. N = 20, p < 0.05 1 tailed) and (ii) to refuse entry to the trial (N = 50, p < 0.05 2 tailed). Those who, given the explicit version, agreed rather than refused to enter the trial, scored higher on believing that others control their health (p < 0.01 2 tailed).

Adult↗
PubMed2005

Are clinical trials in rheumatoid arthritis generalizable to routine practice? A re-evaluation of trial entry criteria.

OBJECTIVE: Trials of disease-modifying anti-rheumatic drugs (DMARDs) enrol active rheumatoid arthritis patients identified using standard criteria (three out of four of: >/=6 tender joints, >/=6 swollen joints, ESR >/= 28 mm/h, >/=45 min morning stiffness). Concern has been expressed about generalizability, as many patients in routine practice have less active disease. Furthermore, these criteria do not map onto standard disease activity and treatment response measures. We examined how many routine patients were sufficiently active to meet trial recruitment criteria and whether alternative definitions of active disease were more appropriate. METHODS: We studied 504 patients in a cross-sectional study, 156 in a longitudinal study and 94 starting new DMARDs or biologics. Patients were classified as 'trial active' (met entry criteria), in remission or 'intermediately active' (between the two). We also evaluated the effect of amendments to criteria. RESULTS: Cross-sectionally only 38% patients were 'trial active', but longitudinally 68% were 'trial active' at least once. Thus, many clinic patients do have disease activity below the level required for trial entry, but over time most reach eligibility levels. More (62%) of the cohort starting new treatment were 'trial active', suggesting that recruitment criteria relate to clinical decisions. Criteria omitting morning stiffness and a disease activity score (DAS28) >/=5.4 replicated the classification given by current criteria. CONCLUSIONS: Trial results can be generalized to routine practice because most clinic patients are 'trial active' when their therapy is changed and most become 'trial active' over time. As DAS-based criteria are simpler and relate directly to response measures, their use should be considered in future.

Adolescent↗
PubMed2005

An evaluation of the introduction of Clinical Trial Officer roles into the cancer clinical trial setting in the UK.

The National Cancer Research Network (NCRN) was created in 2001 to improve the infrastructure for cancer research within the National Health Service (NHS) in the UK and ensure that research is better integrated with cancer care. The NCRN consists of 34 regional networks which map onto the 34 cancer networks that were established following the publication of the NHS Cancer Plan with its aim of improving the coordination and delivery of cancer care and treatment nationally. An objective of the NCRN is to increase recruitment into cancer trials through improved support. One cancer research network responded by introducing Clinical Trial Officers (CTOs) into the cancer clinical trial setting in order to combine the range of tasks required to support clinical trials into a single role with the ultimate aim of increasing recruitment into cancer clinical trials. Evaluation during the first 14 months of their introduction assessed the impact of the new CTO role on cancer trial recruitment, its acceptability to those involved in trials and its effectiveness in achieving increased recruitment. Evaluation identified appropriate induction and training programmes required to support these new roles and the identification of a model for the introduction of CTO posts in other networks across the country. The findings presented in this paper identify that CTO roles can effectively be introduced into a cancer network and have an impact on recruitment to clinical trials within that network. The data collected provided an in-depth insight into how these roles were perceived, have developed and what supporting structures need to be in place to enable them to flourish. Recruitment in the network has increased and there has been a raising of awareness of clinical trials and cancer research across the whole of the cancer network where the CTOs were based. We conclude that CTO roles can offer a creative alternative to staffing cancer clinical trial units and that such a model could be introduced across other networks. Similar models could also be introduced into other disease settings where clinical research is taking place.

Administrative Personnel↗
PubMed1996

Blinding and exclusions after allocation in randomised controlled trials: survey of published parallel group trials in obstetrics and gynaecology.

OBJECTIVE: To assess the methodological quality of approaches to blind ing and to handling of exclusions as reported in randomised trials from one medical specialty. DESIGN: Survey of published, parallel group randomised controlled trials. DATA SOURCES: A random sample of 110 reports in which allocation was described as randomised from 1990 and 1991 volumes of four journals of obstetrics and gynaecology. MAIN OUTCOME MEASURES: The adequacy of the descriptions of double blinding and exclusions after randomisation. RESULTS: Through 31 trials reported being double blind, about twice as many could have been. Of the 31 trials only eight (26%) provided information on the protection of the allocation schedule and only five (16%) provided some written assurance of successful implementation of double blinding. Of 38 trials in which the authors provided sufficient information for readers to infer that no exclusions after randomisation had occurred, six (16%) reported adequate allocation concealment and none stated that an intention to treat analysis had been performed. That compared with 14 (27%) and six (12%), respectively, for the 52 trials that reported exclusions. CONCLUSIONS: Investigators could have double blinded more often. When they did double blind, they reported poorly and rarely evaluated it. Paradoxically, trials that reported exclusions seemed generally of a higher methodological standard than those that had no apparent exclusions. Exclusions from analysis may have been made in some of the trials in which no exclusions were reported. Editors and readers of reports of randomised trials should understand that flawed reporting of exclusions may often provide a misleading impression of the quality of the trial.

Double-Blind Method↗
PubMedDate not supplied

Electronic trial banks: a complementary method for reporting randomized trials.

BACKGROUND: Randomized clinical trial (RCT) results are often difficult to find, interpret, or apply to clinical care. The authors propose that RCTs be reported into electronic knowledge bases-trial banks-in addition to being reported in text. What information should these trial-bank reports contain? METHODS: Using the competency decomposition method, the authors specified the ideal trial-bank contents as the information necessary and sufficient for completing the task of systematic reviewing. RESULTS: They decomposed the systematic reviewing task into four top-level tasks and 62 subtasks. 162 types of trial information were necessary and sufficient for completing these subtasks. These items relate to a trial's design, execution, administration, and results. CONCLUSION: Trial-bank publishing of these 162 items would capture into computer-understandable form all the trial information needed for critically appraising and synthesizing trial results. Decision-support systems that access shared, up-to-date trial banks could help clinicians manage, synthesize, and apply RCT evidence more effectively.

Databases, Factual↗