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Results for “Randomized controlled trials”

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PubMed1989

Quality assessment of randomized controlled trials of contrast media.

Numerous randomized controlled trials (RCTs) have been conducted to define the relative benefits of low-osmolality contrast media (LOM) and high-osmolality contrast media (HOM). Because of the clinical and economic significance of the conclusions drawn from these RCTs, the authors used a standardized instrument to evaluate the quality of study design and data analysis of 100 RCTs published between 1982 and 1987 that compared LOM and HOM. The mean quality score (+/- standard deviation) was 39 +/- 12 (maximum possible score, 100). The largest number of patients studied in any RCT was 435; the smallest was five. A majority of the RCTs received high scores on three attributes of quality, intermediate scores on seven, and low scores on nine. These results underscore the difficulty of designing, performing, analyzing, and reporting high-quality RCTs. Nevertheless, limitations in study design and data analysis need to be considered when interpreting results of these RCTs. Future RCTs comparing LOM and HOM should be performed with greater attention to basic elements of good study design and data analysis.

Clinical Trials as Topic↗

PubMedDate not supplied

The development of a register of randomized controlled trials in prehospital trauma care.

OBJECTIVES: To establish a register of randomized controlled trials of interventions in the prehospital care of trauma patients. METHODS: A systematic search was conducted for all randomized controlled trials of interventions in the prehospital care of trauma patients. The search included the Cochrane Controlled Trial Register, the Cochrane Injuries Group Specialised Register, Medline, EMBASE, the Cumulative Index to Nursing & Allied Health Literature (CINAHL), Science Citation Index, National Research Register, Dissertation Abstracts, and PubMed for the time period 1966-2000. There were no language restrictions. In addition, full-text hand searching of a range of relevant journals was done, and the authors of included trials were contacted. RESULTS: The combined search strategy identified 16,037 potentially eligible records, of which 28 were reports of randomized controlled trials evaluating prehospital trauma care interventions. After excluding duplicate reports, there were 24 separate randomized controlled trials including 6,806 patients. The largest and smallest trials involved 1,309 and 30 trauma patients, respectively. CONCLUSIONS: This register will facilitate the conduct of systematic reviews of the effectiveness of interventions in prehospital trauma care. However, despite the extensive searching, very few randomized trials in this area were found. In view of the absence of evidence for the effectiveness of many of the interventions that are used in the prehospital care of trauma patients, further randomized controlled trials are required.

Emergency Medical Services↗

PubMed2000

Lack of effect of supplementation with essential fatty acids on bone mineral density in healthy pre- and postmenopausal women: two randomized controlled trials of Efacal v. calcium alone.

Randomized controlled trials of the effects of the dietary supplement Efacal (Scotia Pharmaceuticals Plc, Guildford, Surrey, UK) v. Ca only on total body bone mineral density (BMD) and markers of bone turnover were conducted in healthy pre- and postmenopausal women separately. Total daily dose for 12 months for the Efacal groups was: Ca 1.0 g, evening primrose oil 4.0 g and marine fish oil 440 mg; and for the control groups was: Ca 1.0 g. Reported compliance was better than 90% in both age groups. For the forty-three premenopausal women (age range 25-40 years), initial mean total body BMD values were similar for Efacal and control groups and both groups showed highly significant mean increases of about 1%; however, there were no significant between-group differences for the changes in BMD or markers of bone turnover. For the forty-two postmenopausal women (age range 50-65 years), initial mean total body BMD values were again well-matched across treatment groups. Both Efacal and control groups showed highly significant decreases in total body BMD of about 1%, but again there were no significant between-group differences in total body BMD or markers of bone turnover. Possible confounding variables such as initial total body BMD were explored but had no effect on the outcome in either age group. Nail quality improved in both age groups and in both Efacal and control groups. Again, there was no significant difference between treatment groups. No evidence was found to support a beneficial effect of Efacal on BMD in these women.

Adult↗

PubMed1997

Promoting screening mammography in inner-city settings. The sustained effectiveness of computerized reminders in a randomized controlled trial.

OBJECTIVES: The authors conducted a randomized controlled trial to evaluate the sustained effectiveness of a computerized reminder system in promoting mammography during a second year of continuing intervention at three primary care practices of a Health Department and a health maintenance organization in Detroit, Michigan. METHODS: Out-of-pocket mammography cost was eliminated for all participants (limited intervention). Computer-generated reminders promoting physician referral for mammography were placed in the medical records of women due for mammography 1 month in advance of their due date (full intervention). RESULTS: Among 1,225 year 2 visitors, mammography rates were 44% for full intervention versus 28% for limited intervention at the health department (adjusted odds ratio [OR] for effect of full intervention 1.84; 95% confidence interval [CI]: 1.40-2.40) and 45% for full versus 46% for limited at the health maintenance organization (adjusted OR 1.06; 95% CI 0.80-1.42). These second year results contrasted with those observed for year 1, during which a significant effect of full intervention was demonstrated for both organizations. After controlling for patient characteristics and site, the effect sizes of full intervention were reduced significantly in the second year compared with the first year (P = 0.05). CONCLUSIONS: The effect of computerized mammography reminders can be sustained in a second year of continued intervention, but individual practice sites and organizations vary in their responsiveness to the intervention. Strategies to promote periodic and repetitive procedure use must identify and address time-varying barriers to their effectiveness.

Adult↗

PubMed2003

Effect of alendronate and exercise on bone and physical performance of postmenopausal women: a randomized controlled trial.

In this randomized, double-blind, placebo-controlled 12-month trial we evaluated effects of weight- bearing jumping exercise and oral alendronate, alone or in combination, on the mass and structure of bone, risk factors for falling (muscle strength and power, postural sway, and dynamic balance), and cardiorespiratory fitness in postmenopausal women. A total of 164 healthy, sedentary, early postmenopausal women were randomly assigned to one of four experimental groups: (1) 5 mg of alendronate daily plus progressive jumping exercise, (2) 5 mg alendronate, (3) placebo plus progressive jumping exercise, or (4) placebo. The primary endpoint was 12-month change in bone mass and geometry (measured with dual-energy X-ray absorptiometry and peripheral computed tomography at several axial and limb sites) and physical performance; the secondary endpoint was change in biochemical markers of bone turnover. The jumping exercise was conducted an average 1.6 +/- 0.9 (mean +/- SD) times a week. Alendronate daily was effective in increasing bone mass at the lumbar spine (alendronate vs placebo 3.5%; 95% CI, 2.2-4.9%) and femoral neck (1.3%; 95% CI, 0.2-2.4%) but did not affect other bone sites. Exercise alone had no effect on bone mass at the lumbar spine or femoral neck; it had neither an additive nor an interactive effect with alendronate at these bone sites. However, at the distal tibia the mean increase of 3.6% (0.3-7.1%) in the section modulus (that is, bone strength) and 3.7% (0.1-7.3%) increase in the ratio of cortical bone to total bone area were statistically significant in the exercise group compared to the nonexercise group, indicating exercise-induced thickening of the bone cortex. Bone turnover was reduced in alendronate groups only. Alendronate had no effect on physical performance while the jumping exercise improved leg extensor power, dynamic balance, and cardiorespiratory fitness. As conclusion Alendronate is effective in increasing bone mass at the lumbar spine and femoral neck, while exercise is effective in increasing the mechanical properties of bone at some of the most loaded bone sites, as well as improving the participants' muscular performance and dynamic balance. Together alendronate and exercise may effectively decrease the risk of osteoporotic fractures.

Alendronate↗

PubMed1999

Effects of female relative support in labor: a randomized controlled trial.

BACKGROUND: This study was a randomized controlled trial of primigravidas in Botswana to determine the effectiveness of the presence of a female relative as a labor companion on labor outcomes. METHODS: One hundred and nine primigravidas in uncomplicated spontaneous labor were randomly distributed into a control group who labored without family members present, and an experimental group who had a female relative with them during labor. RESULTS: Significantly more mothers in the experimental group had a spontaneous vaginal delivery (91% vs 71%), less intrapartum analgesia (53% vs 73%), less oxytocin (13% vs 30%), fewer amniotomies to augment labor (30% vs 54%), fewer vacuum extractions (4% vs 16%), and fewer cesarean sections (6% vs 13%) than in the control group. These differences were all significant at p < 0.05. Epidural analgesia was not used in the hospital at the time of the study. The only analgesics used were intramuscular pethidine or hyoscine N-butylbromide (Buscopan). CONCLUSIONS: The presence in labor of a female relative was shown to be associated with fewer interventions and a higher frequency of normal delivery compared with the outcomes of those without family member support. The presence of a female relative as a labor companion is a low-cost, preventative intervention that is consistent with the traditional cultural practices in Botswana. In the light of this and previous studies, all women giving birth in a hospital should be offered the choice of a female relative as a companion to give support during labor.

Adult↗

PubMed1997

Assessing social work effectiveness in child care practice: the contribution of randomized controlled trials.

This article discusses the role of randomized controlled trials (RCTs) in evaluating the impact of social work interventions with children. While recognizing the difficulties of applying RCTs to all aspects of practice, we argue that controlled trials can provide the most convincing evidence of the impact of social work activities on the welfare of children and families. Accumulating evidence of the effectiveness of interventions, we propose, should constitute the core business of social work research. To this end, it is necessary to recognize the primacy of the randomized controlled trial in exploring the relationship between social work activities and client outcomes.

Child↗

PubMed1992

Dexamethasone and bacterial meningitis. A meta-analysis of randomized controlled trials.

A meta-analysis of 5 randomized, controlled trials using dexamethasone as adjunctive therapy in the treatment of bacterial meningitis in children was done to assess the efficacy in reducing sequelae. A 6th study including both children and adults was analyzed separately. Results of the 5 pediatric studies indicated no significant difference in case-fatality rate between the placebo and dexamethasone groups. Significantly more neurologic sequelae were found in the placebo group during the period from discharge from hospital to 6 weeks after discharge (relative risk [RR] = 1.99, 95% confidence interval [CI] 1.13 to 3.53) and during the period beginning 6 months after discharge (RR = 3.90, 95% CI 1.72 to 8.85). The incidence of neurologic sequelae from 6 weeks to 6 months after discharge, though less with dexamethasone administration, did not reach statistical significance. The frequency of bilateral hearing loss was significantly greater in the placebo group (RR = 4.12, 95% CI 1.74 to 9.79), but unilateral loss was not statistically different in the two groups. Dexamethasone administration in addition to antimicrobial therapy appears to be effective in reducing neurologic sequelae and bilateral hearing loss associated with bacterial meningitis in children.

Adult↗

PubMed1995

Octreotide and heater probe thermocoagulation for arrest of peptic ulcer hemorrhage. A prospective, randomized, controlled trial.

We carried out a prospective, randomized, controlled trial over a 7-month period to assay the hemostatic effects of octreotide and heater probe thermocoagulation (HPT) in 54 patients with active peptic ulcer bleeding or nonbleeding visible vessels at the ulcer base. Nineteen patients received octreotide 100 micrograms bolus i.v. followed by 25 micrograms/h i.v. for 3 days. Twenty patients received HPT. Fifteen patients received ranitidine 100 mg i.v. every 12 h. The three groups were matched for sex, age, location of bleeders, endoscopic findings, shock, and initial hemoglobin. Ultimate hemostasis was obtained in 11 (58%) of the octreotide group, 18 (90%) of the heater probe group, and 8 (53%) of the control group (p < 0.05). Volume of blood transfused, number of patients receiving operation, hospital stay, and number of deaths were not statistically significant among the three groups. We conclude that HPT is more effective than octreotide in the arrest of peptic ulcer bleeding.

Aged↗

PubMed1990

Intravenous streptokinase in the management of a subset of patients with unstable angina: a randomized controlled trial.

We report the results of a randomized controlled trial of intravenous streptokinase in a subset of patients with unstable angina. Seventy-six patients were admitted with prolonged (more than 20 minutes) angina at rest of less than 3 weeks onset. Fifty-two patients continued to have more than 3 episodes of prolonged angina in 48 hours on medical therapy with metoprolol, isosorbide dinitrate, nifedipine and intravenous nitroglycerin. Forty-eight patients consented to enter the study and were randomized into two groups. The first group, of 24 patients, received 1.5 million units of streptokinase infusion and the second group, also of 24 patients, received a placebo. Pain relief within 48 hours was achieved in 19/24 (79.1%) patients after streptokinase infusion as compared to 9/24 (37.5%) of the controls (P less than 0.05). Approximately 90% (17/19) of patients responding to streptokinase therapy were relieved of chest pain within the first six hours as against none in the controls. The incidence of acute myocardial infarction within six months was 12.5% (3/24) in those receiving streptokinase and 25% (6/24) in the controls. Mortality at six months stood at 8.33% (2/24) in the treated patients and 16.6% (4/24) in the controls. Intravenous streptokinase thus appears to be of benefit in patients with angina at rest of recent onset which does not respond to conventional medical therapy.

Angina Pectoris↗

PubMed2003

Hierarchy of evidence: from case reports to randomized controlled trials.

In the hierarchy of research designs, the results of randomized controlled trials are considered the highest level of evidence. Randomization is the only method for controlling for known and unknown prognostic factors between two comparison groups. Lack of randomization predisposes a study to potentially important imbalances in baseline characteristics between two study groups. There is a hierarchy of evidence, with randomized controlled trials at the top, controlled observational studies in the middle, and uncontrolled studies and opinion at the bottom. This hierarchy has not been supported in two recent publications in the New England Journal of Medicine which identified nonsignificant differences in results between randomized, controlled trials, and observational studies. The current authors provide an approach to organizing published research on the basis of study design, a hierarchy of evidence, a set of principles and tools that help clinicians distinguish ignorance of evidence from real scientific uncertainty, distinguish evidence from unsubstantiated opinions, and ultimately provide better patient care.

Evidence-Based Medicine↗

PubMed1978

The importance of beta, the type II error and sample size in the design and interpretation of the randomized control trial. Survey of 71 "negative" trials.

Seventy-one "negative" randomized control trials were re-examined to determine if the investigators had studied large enough samples to give a high probability (greater than 0.90) of detecting a 25 per cent and 50 per cent therapeutic improvement in the response. Sixty-seven of the trials had a greater than 10 per cent risk of missing a true 25 per cent therapeutic improvement, and with the same risk, 50 of the trials could have missed a 50 per cent improvement. Estimates of 90 per cent confidence intervals for the true improvement in each trial showed that in 57 of these "negative" trials, a potential 25 per cent improvement was possible, and 34 of the trials showed a potential 50 per cent improvement. Many of the therapies labeled as "no different from control" in trials using inadequate samples have not received a fair test. Concern for the probability of missing an important therapeutic improvement because of small sample sizes deserves more attention in the planning of clinical trials.

Clinical Trials as Topic↗

PubMed2003

The evolution of the randomized controlled trial and its role in evidence-based decision making.

The randomized controlled trial has been used in medical research for a little over half a century. This manuscript provides an overview of some of the history and evolution of the randomized controlled trial during this period. There exists hierarchies of evidence for therapeutic, diagnostic and prognostic questions, and the randomized controlled trial is at the top of the therapeutic hierarchy. Despite being at the top of the therapeutic hierarchy randomization in itself does not guarantee the trial results approximate the true effect. Issues that result in systematic and nonsystematic deviations from the truth in randomized controlled trials must also be considered. We present a model for evidence-based decision making that includes the following components: the clinical state, patient preferences, research evidence from a range of studies and clinical expertise. We discuss the role of the randomized controlled trial within evidence-based decision making.

Decision Making↗

PubMed1991

Reduced intravascular catheter infection by antibiotic bonding. A prospective, randomized, controlled trial.

We report a prospective, randomized, controlled clinical trial to evaluate the efficacy of antibiotic-bonded catheters in reducing the incidence of intravascular catheter-related infections. Ninety-three central venous catheters and 85 arterial catheters were studied in the surgical intensive care unit. Study catheters were pretreated with the cationic surfactant tridodecylmethylammonium chloride. The anionic antibiotic, cefazolin, was bonded before insertion of the catheters by immersing them in a 50-mg/mL solution. Fourteen percent of the 81 catheters in the control group were infected, compared with 2% of the 97 antibiotic-bonded catheters. Staphylococcus epidermidis was the most common organism obtained. There was no significant difference in the number of colonized or clinically inflamed catheter insertion sites. None of the 100 antibiotic immersion solutions yielded anything on microbiologic culture. We conclude that antibiotic bonding is an efficient, safe, and cost-effective method of reducing intravascular catheter infection in patients who are in intensive care units.

Bacterial Infections↗

PubMed2002

New drugs with novel therapeutic characteristics. Have they been subject to randomized controlled trials?

OBJECTIVE: To determine how many randomized controlled trials on the safety or efficacy of new drugs are published when these drugs are first marketed in Canada, and to determine the quality of the information in those trials. DESIGN: A MEDLINE search was conducted on each drug identified as having novel therapeutic characteristics and first marketed between 1990 and 2000. MAIN OUTCOME MEASURES: Number of trials dealing with the safety or efficacy of each drug published at the time the drug was marketed. Number of patients taking the study drug, length of the trial, and type of control. RESULTS: The number of trials varied substantially. For some drugs, there were more than 20 studies; for others only a single study. Many trials were small and short-term, and used placebo controls. CONCLUSION: Too few trials or inadequate trials on the safety and efficacy of new drugs are published when these drugs are first marketed in Canada. The lack of published trials means that physicians do not know whether results are generalizable to their patients, how to position the drug in relation to other treatments, or whether the drugs have long-term safety and efficacy.

Canada↗

PubMed1991

Is there an alternative to the randomized controlled trial?

The advantages of the concurrently randomized controlled trial as a device to assess the efficacy of drugs intended for use in the field of psychiatry are reviewed. The importance of "assay sensitivity" is discussed and illustrations of errors that can arise when inferences about efficacy are based upon comparisons that find no difference between experimental and standard treatments are presented. These illustrations are derived from data collected in two different pre-marketing commercial drug development programs. Also discussed is the argument that controlled trials are inappropriate devices to test drug efficacy because of their alleged lack of sensitivity to drug effects.

Humans↗

PubMed2003

Late-starter sites in randomized controlled trials.

In a cohort of 14 randomized controlled trials conducted by the Adult AIDS Clinical Trials Group between 1986 and 1999 with a target sample size of >400 (total enrollment 15,531 patients), we evaluated whether "late-starter" sites can make a meaningful contribution to eventual trial accrual. The sites that started recruiting within 5 months from the time the first patient entered the trial were eventually responsible for over 90% of the total enrollment in 11 of the 14 trials. Across the 14 trials, some sites were consistently among the first to start enrollment, whereas others were routinely among the last. The late-starter sites are unlikely to make important contributions to eventual trial enrollment in large clinical trials conducted by groups with a fixed number of sites. Protracting administrative efforts to add more sites many months after a multicenter trial has started may not be useful to trial accrual.

Acquired Immunodeficiency Syndrome↗

PubMedDate not supplied

The randomized controlled trial in studies using biomarkers.

The randomized controlled trial (RCT) is a scientific experiment during which observations on the effects of therapy or a preventive action are conducted by the researcher under rigorous control. The purpose of the experiment is to clear the uncertainties surrounding a clinical/research issue and involves isolating the 'treatment' and 'end result' variables from external influences. RCTs therefore make use of scientific method standards: measuring, which includes the possibility of reproducing observations; controlling factors unconnected to the cause-effect relationship of interest; and the external verification or 'falsification' of the cause-effect relationship. Many RCTs are now including biomarkers to answer scientific questions in a more accurate way. In the present methodological paper, the main aspects involved in the design and conduction of a trial are discussed, with special emphasis on the use of biomarkers. Aspects that are often overlooked by scientists involved in the design of trials include multiple comparisons, subgroup analysis, the duration of the observations, the use of surrogate endpoints, and ethical issues. This review summarizes the main issues that should be addressed in a protocol, and illustrates these with an example.

Biomarkers↗