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Results for “randomized clinical trial”

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At least 19 recordsLinked to original sources

PubMed1988

Cardiac rehabilitation after myocardial infarction. Combined experience of randomized clinical trials.

Randomized clinical trials of cardiac rehabilitation following myocardial infarction have typically demonstrated a lower mortality in treated patients, but with a statistically significant reduction in only one trial. To overcome the problem of not being able to detect small but clinically important benefits in mortality in randomized clinical trials of exercise and risk factor rehabilitation after myocardial infarction with small numbers of patients, we carried out a meta-analysis on the combined results of ten randomized clinical trials that included 4347 patients (control, 2145 patients; rehabilitation, 2202 patients). The pooled odds ratios of 0.76 (95% confidence intervals, 0.63 to 0.92) for all-cause death and of 0.75 (95% confidence intervals, 0.62 to 0.93) for cardiovascular death were significantly lower in the rehabilitation group than in the control group, with no significant difference for nonfatal recurrent myocardial infarction. These results suggest that, for appropriately selected patients, comprehensive cardiac rehabilitation has a beneficial effect on mortality but not on nonfatal recurrent myocardial infarction.

Aged↗

PubMedDate not supplied

The randomized clinical trial.

Randomized clinical trials were developed to eliminate biases inherent in clinical medicine. Six types of bias that can occur during patient selection and treatment allocation and in the collection and analysis of the data have been identified. A variation of the prospective randomized clinical trial, the nonrandomized surgeon design, overcomes biases specific to surgical investigations.

Animals↗

PubMed1987

The ethics of randomized clinical trials.

Randomized clinical trials pose a number of fundamental ethical problems to which morally sensitive investigators must give careful consideration. The randomized double-blind clinical trial is ethically justified and the preferred method of demonstrating therapeutic effectiveness and safety. Alternate methods such as crossover and self-controlled designs, the use of historical controls, observational methods, and practitioner's clinical trials also exist and have their place in certain circumstances. The use of randomized double-blind clinical trials must assure adequate explanation of the research plan to the patient, the documentation of informed consent, adequate consideration of safety, and an acceptably low risk/benefit ratio.

Clinical Trials as Topic↗

PubMed1989

Treatment of reflux esophagitis with H2-blockers, antacids and prokinetic drugs. An analysis of randomized clinical trials.

Randomized clinical trials comparing H2-receptor antagonists, antacids, antacid/alginate and prokinetic drugs with placebo and other substances were analyzed. Symptomatic improvement has been shown for H2-receptor antagonists, antacids in very high doses and prokinetic drugs. H2-receptor antagonists, the present mainstay of reflux therapy, improve esophagitis, but they are insufficient in the treatment of severe esophagitis where omeprazole may become the therapy of choice. The evidence is weak that antacids, antacid/alginate, metoclopramide and domperidone heal esophagitis.

Antacids↗

PubMedDate not supplied

Ethical issues of randomized clinical trials.

Randomized clinical trials are an accepted form of experimentation on human subjects to determine the effectiveness of new treatment regimens or drugs. The Declaration of Helsinki, adopted by the World Medical Association, has established guidelines to safeguard humans used as subjects in medical experimentation. The ethical issues of informed consent, the physician-patient relationship and the potential for abuses in research must be considered prior to agreeing to participate in human experimentation.

Clinical Protocols↗

PubMed1988

General statistical design considerations of randomized clinical trials.

Randomized clinical trials are the most objective method for evaluating new therapies, but they are subject to the same biases as nonrandomized studies unless the principles of statistical design are observed at the planning stage. Estimation of sample size also requires early careful consideration, since studies of inadequate size will not have sufficient statistical power to detect meaningful treatment differences. For ethical reasons, interim data monitoring procedures should be used to detect early treatment responses that may lead to alteration or interruption of the planned study to give patients early benefit from a superior treatment or diminish their risk from ineffective or harmful treatment. Additional important aspects of clinical trial design that were not addressed in this report include: definition of study objectives and endpoints, description of data to be collected, details of the treatment regimens, informed consent and plans for data analysis. The science of clinical trial design is complex; only some of the key statistical issues have been addressed briefly in this report.

Clinical Trials as Topic↗

PubMed1987

Impact of multiple comparisons in randomized clinical trials.

The randomized clinical trial is the preferred research design for evaluating competing diagnostic and therapeutic alternatives, but confidence in the conclusions from a randomized clinical trial depends on the authors' attention to acknowledged methodologic and statistical standards. This survey assessed the level of attention to the problem of multiple comparisons in the analyses of contemporary randomized clinical trials. Of the 67 trials surveyed, 66 (99 percent) performed multiple comparisons with a mean of 30 therapeutic comparisons per trial. When criteria for statistical impairment were applied, 50 trials (75 percent) had the statistical significance of at least one comparison impaired by the problem of multiple comparisons, and 15 (22 percent) had the statistical significance of all comparisons impaired by the problem of multiple comparisons. Although some statistical techniques are available, there still exists a great need for future work to clarify further the problem of multiple comparisons and determine how the impact of this problem can best be minimized in subsequent research.

Clinical Trials as Topic↗

PubMed1990

Improving physicians' recognition and treatment of depression in general medical care. Results from a randomized clinical trial.

A randomized clinical trial was performed to assess whether the results of a depression screening instrument, when provided to physicians, could influence their recognition and treatment of depression in a primary care setting. The intervention consisted of randomly informing or not informing physicians of the depression status of 100 patients who screened positively for depression on both the Zung Self-rating Depression Scale (SDS) and a DSM-III screen. For 12 months patients were followed to assess depression status, and medical records were audited to assess depression recognition and treatment. Results show that feedback to physicians of SDS scores of previously unrecognized depressed patients makes a significant difference in greater recognition (56.2% vs. 34.6%) and treatment (56.2% vs. 42.3%) of depression over the 12-month study period. This was especially true for patients with high somatic (P less than 0.05) or low psychologic symptoms of depression (P less than 0.05). These results suggest that routine use of a depression screening instrument can improve physician recognition of depression, with increased initiation of treatment.

Clinical Competence↗

PubMed1991

Monitoring a randomized clinical trial for futility: the north-Norwegian lidocaine intervention trial.

Randomized clinical trials of acute disease are usually designed as single-look, fixed sample size trials. This methodological study compares the conventional approach with a multiple-look, group sequential design with stopping rules for both treatment efficacy and for an inconclusive trial outcome, called trial futility. An ongoing trial on pre-hospital prophylaxis of sudden death in acute myocardial infarction forms the basis of the analysis. The effects of introducing multiple looks (or interim analyses) and tests for futility were obtained by binomial simulation. The introduction of four looks (that is, three interim and a final analysis) resulted in a modest increase in the maximal number of patients required. This was, however, fully compensated for by the high probability of early termination in case of treatment efficacy. The addition of futility tests, enabling termination at half the maximum trial size when there is no treatment difference, resulted in only a negligible reduction of overall power. We conclude that multiple-look, group sequential designs testing for both treatment efficacy and trial futility may improve the cost-effectiveness of randomized trials of acute disease.

Binomial Distribution↗

PubMedDate not supplied

Drainage after thyroidectomy: a randomized clinical trial.

A randomized clinical trial of surgical drainage in thyroid surgery was performed on 97 patients. Morbidity was not significantly different between both groups. The length of hospital stay was shorter in the undrained group. However, this RCT is not an indication of the value of drainage after thyroid surgery because the series is too small. Using a meta-analysis of the RCTs reported it is possible to show that to drain is not useful.

Adult↗

PubMed1992

Cutoff assignment strategies for enhancing randomized clinical trials.

The randomized clinical trial (RCT) is the preferred method for assessing the efficacy of treatments. Recent ethical and logistical criticisms suggest that new variations of the traditional RCT are needed. Some of these criticisms may be addressed with new hybrid designs that combine random assignment with assignment by one or more cutoff values on a baseline variable (e.g., severity of illness). In a simple version of such a "cutoff-based" RTC, persons scoring below a cutoff score on a baseline measure (i.e., the least severely ill) are automatically assigned to the control-treated group, those scoring above a second, higher cutoff (i.e., the most ill) are automatically assigned to the test-treated group, and those scoring in the interval between the cutoff scores (i.e., the moderately ill) are randomly assigned to either group. Depending on the baseline score, the patient is assigned to treatment either randomly or by the need-based, clinically related baseline score. Six cutoff-based design variations are studied via simulations and compared with the traditional RCT and the single-cutoff (i.e., regression-discontinuity) design. All variations yield unbiased estimates of the treatment effect but estimates differ in efficiency, with the RCT being most efficient and the single-cutoff design being least efficient. Secondary analyses of data from the Cross-National Collaborative Study of the Effects of Alprazolam (Xanax) on panic are conducted for each variation by selectivity discarding cases from the original dataset to stimulate cutoff-based assignment. The results confirm the simulations and illustrate how cutoff-based designs might look with real data.

Alprazolam↗

PubMedDate not supplied

How much data should we collect in a randomized clinical trial?

Multicentre randomized controlled clinical trials are usually designed to answer a specific question. In accomplishing this they often collect a large quantity of data during screening, baseline and follow-up visits. These data are not all necessarily related to the main study question. This collection impacts on the overall recruitment process and the participants' time. During the planning phase of the trial we need to consider the reasons for collecting data and the use of that data for the current study as well as its potential use in future investigations. We discuss briefly some of the possible reasons that data may be collected: screening or determining eligibility; conducting a run-in or dose titration phase; assessing group comparability; aiding patient management; evaluating the natural history of the disease; monitoring the study; testing the study hypotheses; evaluating adherence; estimating side effects and the use of other therapies; analysis of other study questions.

Data Collection↗

PubMed1991

Three measures for simultaneously evaluating benefits and risks using categorical data from clinical trials.

Randomized clinical trials are typically conducted to compare the efficacy (benefits) and side effects (risks) of two or more treatments. One can use results from such trials to decide on a preferable treatment that reflects one's own evaluation of the benefits and risks. To facilitate the necessary decision making, we propose in this paper three measures for simultaneously assessing benefits and risks. All three measures use weights that reflect the relative importance of the various treatment outcomes to an individual. Two of them carry the flavour of benefit/risk ratios, while the third generalizes Hilden's measure which incorporates patients' preferences. The proposed measures and procedures are illustrated using data from a phase III clinical trial of antihypertensive compounds.

Antihypertensive Agents↗

PubMed1990

Comparison of ceftriaxone (1 x 1 g/day) versus cefotaxime (3 x 1 g/day) for gynecologic and obstetric infections. A randomized clinical trial.

A prospective, randomized clinical trial was conducted to compare the efficacy and tolerance of a single dose of 1 g ceftriaxone i.v. daily with 3 doses of 1 g cefotaxime i.v. daily for obstetric and gynecologic infections. Both agents are characterized by a wide spectrum and potent activity. Furthermore, ceftriaxone has an outstanding serum half-life of 8 h. 41 patients with pelvic inflammatory disease, pelvic or wound infections after vaginal or abdominal hysterectomy, endomyometritis and urinary-tract infection were included. Patients were monitored clinically by routine laboratory methods (erythrocyte sedimentation rate, white blood cell count and cross-reacting protein) and bacteriologically. Clinical parameters of infection were fever, local pain and/or tenderness, a sactosalpinx or pyosalpinx at palpation and cervical secretion. Clinical cure was achieved in 77.3% in the ceftriaxone and in 78.9% in the cefotaxime group, improvement in 3 (13.6%) and 4 patients (21.0%), respectively. 2 clinical failures were seen in the ceftriaxone group. One was a severe pelvic infection following vaginal hysterectomy, which responded to the addition of metronidazole, the other was due to a chlamydial salpingitis, which was cured with a 10-day course of doxycycline. Both antibiotics were well tolerated. Our results suggest that for obstetric and gynecologic infections a single 1-gram dose of ceftriaxone is equally effective as three 1-gram doses of cefotaxime.

Cefotaxime↗

PubMed1985

Fine bore jejunostomy feeding following major abdominal surgery: a controlled randomized clinical trial.

A randomized controlled prospective clinical trial has been undertaken to examine the efficacy of the technique of early postoperative feeding using a fine bore catheter jejunostomy. Fifty patients undergoing surgery for gastrointestinal malignancy were randomly allocated into treatment and control groups. A low residue liquidized diet (Isocal) was administered to the patients in the treatment group. Control patients received routine intravenous therapy. Nutritional parameters (serum albumin, serum transferrin, serum prealbumin, weight, body fat and fat free mass) were measured pre-operatively and on the tenth postoperative day. Postoperative surgical complications were similar in both groups. There were 20 catheter complications and one death directly attributable to the jejunal catheter feeding. Postoperative stay was significantly longer (P less than 0.01) in the treatment group patients. Evaluation of the nutritional parameters showed no advantage for either the treatment group or a selected complication-free, 'successful treatment', subgroup. It is concluded that no significant clinical or nutritional advantage for jejunal catheter feeding has been demonstrated and because of the related complications, its routine use cannot be recommended.

Aged↗

PubMed1985

Prevention of neonatal respiratory distress syndrome by tracheal instillation of surfactant: a randomized clinical trial.

With a randomized clinical trial, the possibility was assessed that a tracheal instillation of pulmonary surfactant prior to the first breath might prevent the development of some of the signs of neonatal respiratory distress syndrome. Of the 72 infants in the trial, all born at a gestational age of less than 30 weeks, 39 received 3 or 4 mL of surfactant, prepared from the lipids extracted from calf lung lavage. The treatment resulted in a significantly improved gas exchange during the first 72 hours of life. On the average, the arterial/alveolar PO2 ratio was 0.15 higher for the treated infants, and only about half as much extra oxygen had to be supplied. The respiratory support (peak inspiratory pressure X frequency) could be lowered significantly. Pulmonary interstitial emphysema occurred in 13 of the 33 control infants, but in only three of the 39 treated infants. Six of the control infants died in the neonatal period, but only one treated infant died. It is concluded that surfactant supplementation prior to the first breath is feasible and is of value as protection against the respiratory distress syndrome and the negative effects of hypoxia and ventilatory support.

Clinical Trials as Topic↗

PubMed1989

Study design for the Triphasic Randomized Clinical Trial.

The Triphasic Randomized Clinical Trial was a multicenter, open-label, controlled, 6-month study to determine the influence of three currently marketed triphasic oral contraceptives on lipid and carbohydrate metabolism, cyclic bleeding profiles, and other adverse drug experiences. The study protocol mandated four clinic visits: an initial visit during which study eligibility was determined, a second visit during which baselines were obtained for lipid and carbohydrate parameters, and visits at 3 and 6 months while taking the study drug. The study enrolled healthy women between the ages of 18 and 35 years who were within 20% of their ideal body weight and who had a history of normal and regular menstrual cycles. Patients were randomly assigned to one of three treatment groups: 51 patients to Tri-Levlen, 50 patients to Ortho-Novum 7/7/7, and 56 patients to Tri-Norinyl. The control group consisted of 49 patients using nonhormonal forms of birth control. Eighty-eight percent (181/206) of the patients completed all four visits and were considered evaluable for subsequent analyses.

Adolescent↗

PubMed1985

The futility index. An approach to the cost-effective termination of randomized clinical trials.

Although the randomized clinical trial is recognized as the method of choice for evaluating therapeutic innovations, it is often enormously expensive--in some instances, as a result of the unnecessary continuation of a trial destined to conclude that an innovation is not superior to standard therapy. Although most large clinical trials in which results evolve over time are monitored for early evidence of efficacy or toxicity, trials are rarely terminated because the probability of a positive result regarding the value of the innovation has become low. This paper discusses the issues involved in the monitoring and early termination of long-term clinical trials and describes the futility index, a probabilistic basis for early termination of trials of innovative therapy when the accumulated data imply small probability of success. Utilization of the futility index in the management of clinical trials of innovations can be of value in reducing, at slight loss of power, the number of unproductive studies carried to completion, thereby creating new opportunities for more effective use of limited resources.

Clinical Trials as Topic↗