[Group allocation by random procedure in field trial (Latin square in working out the list for random allocation) (author's transl)].
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Adolescent↗
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Random allocation or allocation at random? Patients' perspectives of participation in a randomised controlled trial.
OBJECTIVES: To explore trial participants' understandings of randomisation. DESIGN: In this exploratory study, which used qualitative research methods, in-depth, semistructured interviews were carried out with 20 participants from the CLasP randomised controlled trial. Interviews were recorded on audio tape and fully transcribed. Data were analysed by comparing transcripts and describing emergent themes, using a grounded theory approach. SETTING: The CLasP study comprises three linked multicentre, pragmatic randomised controlled trials evaluating the effectiveness and cost effectiveness of laser therapy, standard surgery, and conservative management for men with lower urinary tract symptoms or urinary retention, or both, related to benign prostatic disease. SUBJECTS: 20 participants in the CLasP study were interviewed. Sampling was purposeful: men were included from each of the treatment arms, the two major centres, and at different points in the trial. INTERVENTIONS AND OUTCOME MEASURES: Interviews used a checklist of topics to encourage participants to describe their experiences. Narratives concerning randomisation were compared to identify common themes, retaining the context of the discussion to allow detailed interpretation. RESULTS: Most participants recalled and described aspects of randomisation, such as the involvement of chance, comparison, and concealed allocation. Many found the concept of randomisation difficult, however, and developed alternative lay explanations to make sense of their experiences. Inaccurate patient information and lay interpretations of common trial terms caused confusion. CONCLUSIONS: The provision of clear and accurate patient information is important, but this alone will not ensure consistent interpretation of concepts such as randomisation. Patients may need to discuss the purposes of randomisation in order to understand them fully enough to give truly informed consent.
Attitude to Health↗
Lay conceptions of the ethical and scientific justifications for random allocation in clinical trials.
Randomised controlled trials (RCTs) play a central role in modern medical advance, and they require participants who understand and accept the procedures involved. Published evidence suggests that RCT participants often fail to understand that treatments are allocated at random and that clinicians are in equipoise about which treatment is best. We examine background assumptions that members of the public might draw upon if invited to take part in a RCT. Four studies (N=82; 67; 67; 128), in the UK, identified whether members of the public (i). accept that an individual clinician might be genuinely unsure which of two treatments was better; (ii). judge that when there is uncertainty it is acceptable to suggest deciding at random; (iii). recognise scientific benefits of random allocation to treatment conditions in a trial. Around half the participants were loathe to accept that a clinician could be completely uncertain, and this was no different whether the context was one of individual treatment or research. Most participants found it unacceptable to suggest allocating treatment at random, though there was weak evidence that a research context may reduce the unacceptability. Participants did not judge that more certain knowledge would be gained about which treatment was best when treatments were allocated at random rather than by patient/doctor choice: scientific benefits of randomisation were apparently not recognised. Judgements were no different in non-medical contexts. Results suggest a large mismatch between the assumptions underlying the trial design, and the assumptions that lay participants can bring to bear when they try to make sense of descriptive information about randomisation and equipoise. Previous attempts to improve understanding by improving the clarity or salience of trial information, or of making explicit the research context, while helpful, may need to be supplemented with accessible explanations for random allocation.
Adult↗
Random allocation software for parallel group randomized trials.
BACKGROUND: Typically, randomization software should allow users to exert control over the different aspects of randomization including block design, provision of unique identifiers and control over the format and type of program output. While some of these characteristics have been addressed by available software, none of them have all of these capabilities integrated into one package. The main objective of the Random Allocation Software project was to enhance the user's control over different aspects of randomization in parallel group trials, including output type and format, structure and ordering of generated unique identifiers and enabling users to specify group names for more than two groups. RESULTS: The program has different settings for: simple and blocked randomizations; length, format and ordering of generated unique identifiers; type and format of program output; and saving sessions for future use. A formatted random list generated by this program can be used directly (without further formatting) by the coordinator of the research team to prepare and encode different drugs or instruments necessary for the parallel group trial. CONCLUSIONS: Random Allocation Software enables users to control different attributes of the random allocation sequence and produce qualified lists for parallel group trials.
Algorithms↗
An easily customized, random allocation system using the minimization method for multi-institutional clinical trials.
In a randomized clinical trial, random allocation of patients to treatment groups should be done to balance in the distribution of prognostic factors. Random allocation in a multi-institutional randomized clinical trial is conducted by a coordinating center, independent of the medical institution the attending doctor uses for his/her practice. This study provides a sophisticated system for doing an exact random allocation of patients to treatment groups. The minimization method proposed by Pocock was applied to this system to balance the distribution of prognostic factors between two treatment groups, even when the number of registered patients is relatively small (S.J. Pocock, Allocation of patients to treatment in clinical trial, Biometrics 35 (1979) 183-197). Furthermore, Zelen's method is used to balance the number of patients allocated to the two groups within each institution (M. Zelen, The randomization and stratification of patients to clinical trials, J. Chron. Dis. 27 (1974) 365-375.). This system was created by the 'PERL’ language for writing common gateway interface (CGI) script, and can therefore, be easily extended to include data entry function by attending doctors as well as the random allocation function. This system is being used effectively in thirteen multi-institutional randomized clinical trials for stomach, colon-rectum and breast cancers in Japan.
Clinical Trials as Topic↗
A generic minimization random allocation and blinding system on web.
BACKGROUND: Minimization is a dynamic randomization method for clinical trials. Although recommended by many researchers, the utilization of minimization has been seldom reported in randomized trials mainly because of the controversy surrounding the validity of conventional analyses and its complexity in implementation. However, both the statistical and clinical validity of minimization were demonstrated in recent studies. Minimization random allocation system integrated with blinding function that could facilitate the implementation of this method in general clinical trials has not been reported. SYSTEM OVERVIEW: The system is a web-based random allocation system using Pocock and Simon minimization method. It also supports multiple treatment arms within a trial, multiple simultaneous trials, and blinding without further programming. METHODS: This system was constructed with generic database schema design method, Pocock and Simon minimization method and blinding method. It was coded with Microsoft Visual Basic and Active Server Pages (ASP) programming languages. And all dataset were managed with a Microsoft SQL Server database. Some critical programming codes were also provided. SIMULATIONS AND RESULTS: Two clinical trials were simulated simultaneously to test the system's applicability. Not only balanced groups but also blinded allocation results were achieved in both trials. DISCUSSIONS AND CONCLUSIONS: Practical considerations for minimization method, the benefits, general applicability and drawbacks of the technique implemented in this system are discussed. Promising features of the proposed system are also summarized.
Clinical Trials as Topic↗
The prophylactic use of diclofenac (Voltarol) suppositories in perineal pain after episiotomy. A random allocation double-blind study.
One hundred and ten patients who had episiotomies to aid normal vaginal delivery without epidural analgesia were = allocated at random to receive either diclofenac (n = 56) or = placebo (n = 54) suppositories. Pain after episiotomy was assessed at 24 and 48 hours using a combination of a visual analogue scale, a modified pain score and a review of additional analgesia required. All patients in both groups were allowed routine hospital analgesia on request. Our data suggests that very few patients suffered severe pain, even in the placebo group. However, the prophylactic use of diclofenac suppositories significantly reduced perineal pain in the first 24 hours, although the difference was less marked by 48 hours. Overall additional analgesia requirement was correspondingly less in the diclofenac group.
Journal Article↗
Blastomeres from somatic cell nuclear transfer embryos are not allocated randomly in chimeric blastocysts.
A marker has been developed to allow detection of blastomeres that originate from embryos produced by nuclear transfer (NT) of genetically engineered fetal fibroblasts. A plasmid (phEFnGFP) was constructed with a G418 resistance cassette for selection in fibroblasts and a nuclear localized green fluorescent protein (nGFP) expression cassette that expresses in every cell of day-6, -7, and -8 bovine embryos. This construct was utilized to follow the blastomere distribution in aggregation chimeras produced from fertilized embryos (in vitro produced, IVP) or parthenotes and NT embryos. Fluorescent and nonfluorescent NT embryos were aggregated early on day 4 and evaluated on day 8. Nuclei of blastomeres that carried the transgene were fluorescent under both UV epifluorescence (Hoechst 33342) and blue epifluorescence (nGFP). There was no bias in the distribution of green fluorescent blastomeres in the inner cell mass (ICM) or trophectoderm in NT<>NT chimeras. However, there was a strong bias for NT blastomeres to populate the ICM when aggregated with IVP embryos or parthenotes. There was also a strong bias against NT blastomeres in the trophectoderm when aggregated to IVP embryos. However, the bias against NT blastomeres in the trophectoderm was significantly less (p < 0.05) when aggregated with parthenotes as compared to aggregation with IVP embryos. In NT<>NT aggregates, no chimeric embryos were produced that had an ICM composed of blastomeres from a single origin. However, in NT<>Parthenote aggregates, 67% of the blastocysts had an ICM composed exclusively of NT origin. The remaining blastocysts ranged from 0% to 83% of the ICM that expressed nGFP. Similarly, in NT<>IVP aggregates 50% of the blastocysts had an ICM composed exclusively of NT origin. The remaining blastocysts ranged from 19% to 71% of the ICM being of NT origin. We conclude that production of divaricated chimeras from NT origin is feasible. Other applications of this technology are discussed.
Animals↗
Making sense of randomization; responses of parents of critically ill babies to random allocation of treatment in a clinical trial.
Randomized controlled trials (RCTs) are widely accepted by the scientific community as the most rigorous way of evaluating interventions in health care. Although their central feature, random allocation of treatment, is generally seen as methodologically appropriate, its application has caused much debate amongst health professionals and ethicists. This paper describes the views of parents who consented that their critically ill newborn baby should be enrolled in a neonatal trial. In-depth interviews were used to determine their response to the trial and randomization. The nature of the trial was often poorly understood. The random basis of the allocation of treatment and the rationale behind this approach were also problematic issues. Some parents did not perceive a random element in the process at all. These findings advance understanding of the perceptions of trial participants and raise important issues for those concerned with RCTs. Greater understanding of participants' views provides the potential to improve the management of future trials and so the experience of those agreeing to take part.
Adult↗
Bone metastasis: review and critical analysis of random allocation trials of local field treatment.
PURPOSE: Compare and contrast reports of random allocation clinical trials of local field radiation therapy of metastases to bone to determine the techniques producing the best results (frequency, magnitude, and duration of benefit), and relate these to the goals of complete relief of pain and prevention of disability for the remaining life of the patient. METHODS AND MATERIALS: Review all published reports of random allocation clinical trials, and perform a systematic analysis of the processes and outcomes of the several trial reports. RESULTS: All trials were performed on selected populations of patients with symptomatic metastases and most studies included widely diverse groups with regard to: (a) site of primary tumor, (b) location, extent, size, and nature of metastases, (c) duration of survival after treatment All trial reports lack sufficient detail for full and complete analysis. Much collected information is not now available for reanalysis and many important data sets were apparently never collected. Several of the variations in patient and tumor characteristics were found to be much more important than treatment dose in the outcome results. Treatment planning and delivery techniques were unsophisticated and probably resulted in a systematic delivery of less than the assigned dose to some metastases. In general the use and benefit of retreatment was greater in those patients who initially received lower doses but the basis and dose of retreatment was not documented. Follow-up of patients was varied with a large proportion of surviving patients lost to follow-up in several studies. The greatest difference in the reports is the method of calculation of results. The applicability of Kaplan-Meier actuarial analysis, censoring the lost and dead patients, as used in studies with loss to follow-up of a large number of patients is questionable. The censoring involved is "informative" (the processes of loss relate to the outcome) and not acceptable since it results in artificial elevation of the frequency of response. Overall, higher dose fractionated treatment regimens produced a better frequency, magnitude, and duration of response than lower dose single-fraction regimens. Relapse after initial response was frequent. The "median duration of relief" was much shorter than the "median duration of survival" post-treatment. Thus the "net pain relief" is far less than the goal of pain relief for the total duration of life after treatment. CONCLUSIONS: The pain relief obtained in all studies is poor and our care practices need to be improved. Many patients never achieved complete relief and for most who did, the duration of relief was much less than their period of survival after treatment. Higher dose, fractionated treatments produced a greater frequency, magnitude, and duration of response with an improved "net pain relief." Additional trials with selection of comparable cases, good definition of extent of disease, exemplary treatment, and complete follow-up are required.
Analgesics↗
A flexible random allocation program for multi-institutional clinical trials.
This paper describes a flexible random allocation program that assigns treatments to patients according to their prognostic factors in multi-institutional clinical trials. The source lists are available in the appendix of this paper. This program is based on Pocock and Simon's minimization method and Zelen's method for institution balancing. The numbers of institutions, treatments, and prognostic factors can be set arbitrarily. The maximum number of institutions, treatments, or prognostic factors that can be accommodated by the program is limited only by the size of the main memory. For example, an IBM-PC with a 640KB main memory can run a program of 1500 institutions, 4 treatments and 20 prognostic factors.
Humans↗
A World Wide Web-based user interface for a data management system for use in multi-institutional clinical trials--development and experimental operation of an automated patient registration and random allocation system.
We have employed the Hypertext Transfer Protocol (HTTP) and Hypertext Markup Language (HTML) to develop an automated patient registration and random allocation system for use in a multi-institutional clinical trial. We made it available on-line to World Wide Web clients in each hospital through a user friendly graphical user interface. During experimental operation, the physicians found it satisfactory from the viewpoint of both ease of operation and response time. For the development of a graphical user interface in network-based information system for use in multi-institutional clinical trials, HTTP/HTML has several advantages over an ordinary client-server model. Therefore, we concluded that we would adopt HTP/HTML for the construction of user interfaces for physicians in each spital and for data managers in our coordinating center.
Chemotherapy, Adjuvant↗
A random allocation system with the minimization method for multi-institutional clinical trials.
This paper describes the random allocation system used to perform precise and rapid treatment assignments in multi-institutional clinical trials. This system is based on sophisticated randomization procedures, according to Pocock and Simon's minimization method and Zelen's method for institution balancing. The major advantage of randomized treatment assignments with this system is to balance treatment numbers for each level of various prognostic factors over the entire trial and at the same time balance the allocation of treatments within an institution. Therefore, the randomized treatment assignments by this system can prevent degrading of the statistical power of a particular treatment factor. This system is designed to run on a small-sized notebook computer and therefore can be set up beside a telephone for registration, without occupying a large space. At present, this system is conveniently being used in two clinical trials.
Algorithms↗
Outcome of outpatient psychotherapy in a random allocation treatment study of anorexia nervosa.
Ninety subjects with DSM-III-R anorexia nervosa were randomly allocated to four treatment options, one inpatient, two outpatient, and one comprising an assessment interview only. Twenty were thus offered a package of outpatient individual and family psychotherapy. At 2-year follow-up, 12 of the 20 were classed as well, or very nearly well, according to operationally defined criteria. Statistically significant improvements over time were obtained for weight, mean body mass index (BMI), and also for psychological, sexual, and socioeconomic adjustments. Weight and BMI changes were significantly better than for the assessment only group, some of whom had received extensive treatment elsewhere. The style of the outpatient therapy and compliance with it are described in some detail and prognostic indicators for the treated and untreated groups presented. Lower weights at presentation and vomiting were associated with poorer outcome, although age and length of history were not.
Adaptation, Psychological↗
UKPDS 18: estimated dietary intake in type 2 diabetic patients randomly allocated to diet, sulphonylurea or insulin therapy. UK Prospective Diabetes Study Group.
Self-reported dietary intake was estimated from 3-day prospective food diaries completed by Type 2 diabetic patients in the UK Prospective Diabetes Study. All patients had received individual dietary advice and had been randomly allocated to diet, sulphonylurea or insulin therapy 3 months after diagnosis. A total of 132 patients (120 white Caucasian, 12 Asian) stratified for gender, obesity and allocated therapy with mean age 55 years (SD 8), body mass index 28 kg m-2 (SD 4), and with a diabetes duration of 3 to 6 years were selected at random from 5 of 23 clinical centres. Patients reported a similar proportion of their energy intake as carbohydrate (43%) to the general population and had not increased to the recommended 50-55%. Their protein intake (21%) was higher than the advised 10-15%. Estimated energy intake from fat (37%) was close to that recommended for diabetic patients (30-35%) and was lower than that reported for the UK population (40%). The estimated polyunsaturated/saturated fat intake ratio (0.48) was higher than that reported for the UK population (0.35) compared with the recommended 1.0. Mean fibre intake at 22 g day-1 was less than the recommended 30 g day-1. The 8 male Asian patients took a higher proportion of their dietary intake as fat (46% vs 37%) and lower as protein (14% vs 21%) than the male white Caucasian patients. No significant differences were seen in estimated nutrient constituents between patients allocated to diet, sulphonylurea or insulin therapy as part of the UK Prospective Diabetes Study and followed for mean 4.2 years (SD1.6). This suggests that dietary factors will not confound UK Prospective Diabetes Study treatment related analyses.
Cross-Sectional Studies↗
Primary and secondary prevention of myocardial infarction and strokes: an update of randomly allocated, controlled trials.
AIM: To summarize the risk factors associated with coronary heart disease and strokes and to evaluate measures used in the prevention and treatment of these diseases. METHOD: A review of the results of randomly allocated clinical trials of treatment for both primary and secondary prevention of coronary heart disease and strokes. RESULTS: Reductions in elevated blood pressure and cholesterol and cessation of cigarette smoking have clearly been shown to reduce the incidence of coronary heart disease. A reduction in blood pressure has also been shown to reduce the risk of strokes. In addition to other classical risk factors, such as abnormal serum lipids, diabetes and a genetic predisposition, recent studies have shown that elevated levels of fibrinogen and other clotting factors, elevated levels of renin and decreased levels of anti-oxidant vitamins such as E, C and beta-carotene can predict coronary heart disease and strokes. Thrombolytic therapy, aspirin and beta-blockers have been shown to reduce mortality in patients with myocardial infarction, and the latter two agents reduce mortality, re-infarction and strokes with long-term use. Treatment with intravenous magnesium and nitrates has shown promise but larger trials are required to confirm the results. Both aspirin and heparin have proven value in reducing the incidence of myocardial infarction and death in unstable angina. Following an acute myocardial infarction, long-term therapy with aspirin, beta-blockers, lipid-lowering agents and oral anticoagulants has been shown to reduce mortality and re-infarction. In patients with large infarcts associated with a low ejection fraction or heart failure, the use of angiotensin converting enzyme (ACE) inhibitors reduces mortality, hospitalization for heart failure and re-infarction. The use of diuretics to lower blood pressure reduces strokes. In contrast, calcium antagonists do not appear to consistently reduce mortality or prevent vascular events when used for primary or secondary prevention of either myocardial infarction or strokes. CONCLUSIONS: Myocardial infarction and strokes can be prevented by refraining from smoking and maintaining appropriate blood pressure levels and a favourable balance of lipids. Following a myocardial infarction, further drug treatment should include aspirin, thrombolytic therapy (in acute myocardial infarction), beta-blockers, ACE inhibitors (in patients with a low ejection fraction) and perhaps anticoagulants.
Adrenergic beta-Antagonists↗
Randomly allocated study of the effects of standard therapy versus ACE inhibition on micro-albuminuria in essential hypertension.
OBJECTIVE: To compare the effects of standard therapy (diuretic, beta-blocker or both) with those of angiotensin converting enzyme (ACE) inhibition with quinapril on renal function and urinary albumin excretion in patients with essential hypertension. METHODS: A 1-year, placebo-controlled, randomly allocated study was conducted in a group of 40 patients with essential hypertension. Before beginning the active treatment phase, all patients were given a matched placebo for quinapril for at least 14 days. At baseline and after 1, 3, 6 and 12 months of treatment, blood pressure, heart rate, body weight, renal plasma flow, glomerular filtration rate, plasma renin activity, plasma aldosterone and urinary albumin excretion were measured. RESULTS: Both the standard therapy and quinapril produced similar decreases in blood pressure, but only quinapril produced a significant decrease in micro-albuminuria, from 68.5 +/- 16.7 to 47.2 +/- 14.9 mg/24 h (P < 0.05). The renal plasma flow remained constant in both study groups while the glomerular filtration rate and filtration fraction decreased significantly (P < 0.05) in the quinapril group. CONCLUSIONS: The results of this study indicate that long-term therapy for essential hypertension with ACE inhibition has a more favorable effect on micro-albuminuria than standard therapy for an equal level of blood pressure control.
Adrenergic beta-Antagonists↗
Effects of lisinopril and hydrochlorothiazide on platelet function and blood rheology in essential hypertension: a randomly allocated double-blind study.
AIM: To compare the effects of an angiotensin converting enzyme (ACE) inhibitor and a thiazide diuretic on platelet function and haemorrheological variables, since these factors may contribute to the atherosclerotic and thrombotic complications associated with hypertension. METHODS: Following a 2-week placebo period, 80 male and female patients with mild to moderate hypertension, aged 50 +/- 10 (mean +/- SD) years, were randomly allocated in a double-blind study to 4 weeks of treatment with the ACE inhibitor lisinopril at 20 mg once a day or the diuretic hydrochlorothiazide at 25 mg once a day. Venous blood was sampled before and at the end of the 4-week treatment period to assess platelet function and haemorrheological variables. RESULTS: Both treatments lowered systolic and diastolic blood pressure equally and had no significant effect on platelet counts and platelet aggregation in response to ADP and to arachidonic acid. Haematocrit plasma viscosity and blood filterability were not altered by either drug. Hydrochlorothiazide tended to increase and lisinopril tended to decrease whole blood viscosity at all shear rates but these changes did not reach statistical significance. Lisinopril increased the erythrocyte aggregation time (from 1.98 +/- 0.50 to 2.08 +/- 0.52 s) and decreased the disaggregation shear rate (from 159 +/- 46 to 153 +/- 40 s-1) and the disaggregation shear stress (from 705 +/- 257 to 659 +/- 204 mPa). Hydrochlorothiazide induced the opposite effects (2.00 +/- 0.47 to 1.92 +/- 0.39 s, 181 +/- 531 to 196 +/- 82 s-1 and 813 +/- 268 to 868 +/- 392 mPa, respectively) with a statistically significant (P < 0.05) intergroup difference. CONCLUSIONS: These findings suggest that chronic treatment with the ACE inhibitor lisinopril, but not the diuretic hydrochlorothiazide, may produce favourable effects on blood rheology, but the clinical relevance requires further investigation.
Adult↗