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Results for “Randomized Controlled Trial”

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At least 19 recordsLinked to original sources
PubMed2002

Can vitamin D supplementation reduce the risk of fracture in the elderly? A randomized controlled trial.

Randomized controlled trials have shown that a combination of vitamin D and calcium can prevent fragility fractures in the elderly. Whether this effect is attributed to the combination of vitamin D and calcium or to one of these nutrients alone is not known. We studied if an intervention with 10 microg of vitamin D3 per day could prevent hip fracture and other osteoporotic fractures in a double-blinded randomized controlled trial. Residents from 51 nursing homes were allocated randomly to receive 5 ml of ordinary cod liver oil (n = 569) or 5 ml of cod liver oil where vitamin D was removed (n = 575). During the study period of 2 years, fractures and deaths were registered, and the principal analysis was performed on the intention-to-treat basis. Biochemical markers were measured at baseline and after 1 year in a subsample. Forty-seven persons in the control group and 50 persons in the vitamin D group suffered a hip fracture. The corresponding figures for all nonvertebral fractures were 76 persons (control group) and 69 persons (vitamin D group). There was no difference in the incidence of hip fracture (p = 0.66, log-rank test), or in the incidence of all nonvertebral fractures (p = 0.60, log-rank test) in the vitamin D group compared with the control group. Compared with the control group, persons in the vitamin D group increased their serum 25-hydroxyvitamin D concentration with 22 nmol/liter (p = 0.001). In conclusion, we found that an intervention with 10 microg of vitamin D3 alone produced no fracture-preventing effect in a nursing home population of frail elderly people.

Aged↗
PubMed2006

Assessing the effectiveness of antiretroviral adherence interventions. Using marginal structural models to replicate the findings of randomized controlled trials.

Randomized controlled trials of interventions to improve adherence to antiretroviral medications are not always feasible. Marginal structural models (MSM) are a statistical methodology that aims to replicate the findings of randomized controlled trials using observational data. Under the assumption of no unmeasured confounders, 3 MSM estimators are available to estimate the causal effect of an intervention. Two of these estimators, G-computation and inverse probability of treatment weighted (IPTW), can be implemented using standard software. G-computation relies on fitting a multivariable regression of adherence on the intervention and confounders. Thus, it is related to the standard multivariable regression approach to estimating causal effects. In contrast, IPTW relies on fitting a multivariable logistic regression of the intervention on confounders. This article reviews the implementation of these methods, the assumptions underlying them, and interpretation of results. Findings are illustrated with a theoretic data example in which MSM are used to estimate the effect of a behavioral intervention on adherence to antiretroviral therapy.

Anti-HIV Agents↗
PubMed1988

Antiplatelet agents in the secondary prevention of stroke: meta-analysis of the randomized control trials.

Randomized control trials of antiplatelet agents in the prevention of stroke following transient ischemic attacks have had conflicting results. The decision to employ aspirin instead of placebo as the control regimen in trials testing newer antiplatelet agents emphasizes the need for an accurate estimate of the efficacy of older drugs. A meta-analysis of seven randomized control trials comparing aspirin and/or sulfinpyrazone or dipyridamole with placebo was performed. For aspirin compared with placebo, a nonsignificant reduction in stroke of 15% (odds ratio 0.85, 95% confidence interval 0.60-1.19; chi 2 = 0.78, p greater than 0.30) was found. For aspirin combined with sulfinpyrazone or dipyridamole compared with placebo, a 39% reduction in stroke was observed (odds ratio 0.61, 95% confidence interval 0.39-0.95; chi 2 = 4.22, p less than 0.05); at the same time a 350% increase in gastrointestinal hemorrhage or peptic ulcer was noted (odds ratio 3.5, 95% confidence interval 1.26-9.75; chi 2 = 4.61, p less than 0.05). A trend in reduction of strokes for men was observed (odds ratio 0.58, 95% confidence interval 0.32-1.07; chi 2 = 2.52, p less than 0.15) for any regimen containing aspirin. The significant benefit of aspirin-combination therapy on stroke must be interpreted cautiously because of a number of possible biases. It is still conceivable that aspirin alone may decrease the incidence of stroke by as much as 40%, but a sample of greater than 13,000 patients would be needed to confirm the benefit observed in our analysis.

Aspirin↗
PubMed1996

Therapeutics and inflammatory bowel disease: a guide to the interpretation of randomized controlled trials.

Randomized controlled trials are the optimal means of assessing the efficacy of new treatments. This report reviews the methodology of clinical trials in inflammatory bowel disease using examples from recent randomized trials of therapy for Crohn's disease and other gastrointestinal diseases to show key principles. Guidelines for the practicing clinician to evaluate these studies are provided.

Guidelines as Topic↗
PubMed1999

Challenges in palliative care research; recruitment, attrition and compliance: experience from a randomized controlled trial.

Randomized controlled trials (RCTs) in palliative cancer care often experience methodological problems. In this paper we discuss issues of major concern, including recruitment, patient attrition and compliance, arising from an RCT that compared comprehensive palliative care to conventional care. The main criteria for trial entry were incurable malignant disease and a survival expectancy of between 2 and 9 months. Patients' health-related quality of life (HRQL), self-assessed by multi-item questionnaires, was a defined endpoint. The planned number of patients was successfully recruited, although the patients were referred late in the course of their disease so that follow-up tended to be short. Compliance in completing HRQL questionnaires was good up to 1 month before the patient's death; but in the final weeks it was found to drop substantially. Based on our experience, recommendations are given for those planning similar research. Procedures for improving patient recruitment are suggested, stressing the need for local data management, repeated information to referral sources, extensive screening for potentially eligible patients and simple referral routines. Precise inclusion criteria, including prognostic factors other than physicians' estimates of life expectancy, should be used to ensure a sufficient follow-up period. For HRQL assessment, multi-item questionnaires can achieve excellent compliance up to 1 month before patients' death, but in order to evaluate the very final weeks of life we recommend the use of simpler methods.

Adult↗
PubMed2005

Statistical power for analyses of changes in randomized controlled trials.

Randomized controlled trials (RCTs) are widely recommended as the most useful study design to generate reliable evidence and guidance to daily practices in medicine and dentistry. However, it is not well-known in dental research that different statistical methods of data analysis can yield substantial differences in study power. In this study, computer simulations are used to explore how using different univariate and multivariate statistical methods of analyzing change in continuous outcome variables affects study power, and the sample size required for RCTs. Results show that, in general, analysis of covariance (ANCOVA) yields greater power than other statistical methods in testing the superiority of one treatment over another, or in testing the equivalence between two treatments. Therefore, ANCOVA should be used in preference to change score or percentage change score to reduce type II error rates.

Analysis of Variance↗
PubMed2006

Morning compared with evening induction of labor: a nested randomized controlled trial. A nested randomized controlled trial.

OBJECTIVE: To test the hypothesis that commencing induction of labor in the morning more closely reflects the physiologic timing of onset of labor and is associated with fewer women who remain undelivered 24 hours after cervical ripening and induction begins. METHODS: This was a nested randomized clinical trial, conducted between April 2001 and December 2004. Pregnant women at more than 36+6 weeks gestation with a cephalic presentation who were scheduled for prostaglandin induction of labor were eligible to participate. Women were randomly assigned to either admission in the morning (0800 hours) or admission in the evening (2,000 hours). The primary outcome measures were vaginal birth not achieved in 24 hours, uterine hyperstimulation with associated fetal heart rate changes, and cesarean delivery. RESULTS: A total of 620 women were entered in the trial, with 280 women in the morning admission group and 340 women in the evening admission group. There were no statistically significant differences between the timing of admission for induction and the primary trial outcomes. However, women admitted in the morning were less likely to require oxytocin infusion (morning admission 126 of 280 [45.0%] compared with evening admission 184 of 340 [54.1%]; relative risk 0.83, 95% confidence interval 0.70-0.97; P=.022). Nulliparous women admitted in the morning were less likely to require operative vaginal birth (morning admission 10 of 62 [16.1%] compared with evening admission 28 of 82 [34.2%]; relative risk 0.47, 95% confidence interval 0.25-0.90; P=.015). CONCLUSION: For women who require induction of labor, consideration should be given to admission in the morning rather than admission in the evening. CLINICAL TRIAL REGISTRATION: Australian Clinical Trials Registry, www.actr.org.au, 12606000156583.

Adult↗
PubMed1998

Effect of intensive therapy on residual beta-cell function in patients with type 1 diabetes in the diabetes control and complications trial. A randomized, controlled trial. The Diabetes Control and Complications Trial Research Group.

BACKGROUND: Although insulin secretion is severely decreased in most patients with type 1 diabetes, levels of residual insulin secretion often vary early in the disease. The significance of residual insulin secretion with regard to metabolic control and to long-term complications and ways to preserve such secretion are not well understood. OBJECTIVE: To compare the effects of intensive and conventional therapy on residual insulin secretion in Diabetes Control and Complications Trial (DCCT) participants. DESIGN: Multicenter, randomized, controlled clinical trial. SETTING: 29 DCCT clinical centers. PATIENTS: 855 of the 1441 DCCT participants had had type 1 diabetes for 1 to 5 years at baseline. Of these 855 patients, 303 were C-peptide responders (C-peptide level, 0.20 to 0.50 pmol/mL after ingestion of a standardized, mixed meal); 138 of these patients were randomly assigned to intensive therapy, and 165 were assigned to conventional therapy. Five hundred fifty-two patients were nonresponders (stimulated C-peptide level < 0.2 pmol/mL); 274 of these patients were assigned to intensive therapy, and 278 were assigned to conventional therapy. INTERVENTIONS: 1) Intensive therapy with 3 or more insulin injections daily or continuous subcutaneous infusion of insulin, guided by 4 or more glucose tests per day or 2) conventional therapy with 1 or 2 insulin injections daily. MEASUREMENTS: Stimulated C-peptide level was measured annually in responders. Development of retinopathy and microalbuminuria was assessed annually, hemoglobin A1c levels were measured quarterly, and episodes of hypoglycemia were ascertained quarterly. RESULTS: Responders receiving intensive therapy maintained a higher stimulated C-peptide level and a lower likelihood of becoming nonresponders than did responders receiving conventional therapy (risk reduction, 57% [95% CI, 39% to 71%]; P < 0.001). As in the entire DCCT cohort, intensively treated responders had a reduced risk for retinopathy progression and development of microalbuminuria and a higher risk for severe hypoglycemia compared with conventionally treated responders. Among intensively treated patients, responders had a lower hemoglobin A1c value (P < 0.01), a 50% (95% CI, 12% to 72%) reduced risk for retinopathy progression, and a lower risk for severe hypoglycemia (risk reduction, 65% [CI, 53% to 74%]; P < 0.001) compared with nonresponders. CONCLUSIONS: Intensive therapy for type 1 diabetes helps sustain endogenous insulin secretion, which, in turn, is associated with better metabolic control and lower risk for hypoglycemia and chronic complications. These observations underscore the importance of initiating intensive diabetic management as early as safely possible after type 1 diabetes is diagnosed.

Adolescent↗
PubMed1990

Screening elderly people in primary care: a randomized controlled trial.

A randomized controlled trial was carried out to test the effectiveness of a screening programme carried out by nurses for elderly people aged 75 years and over in a general practice. A total of 151 people were randomly allocated to the test group and 145 to the control group. The test group received a home visit from a nurse at which an assessment lasting 45 minutes was made of: activities of daily living, social functioning, sensory functions, mental and emotional problems, current medical problems, blood pressure, urinalysis, haemoglobin level and compliance with medication. Both groups completed a selection of items from four health indices before and 20 months after the intervention. At follow up, the test group scored significantly better than the control group on a morale scale. However, this trial provided no evidence for better resolution of physical problems or finding activities of daily living easier in the test group compared with the control group. It is suggested that the main benefit of such a screening process is that the special attention and education provided improves adaptation to old age and awareness of the support systems available. The government has proposed an annual review of elderly people in their own home and this study suggests that the objectives of this scheme should be clarified.

Aged↗
PubMed1997

Quality and retrieval of obstetrical anaesthesia randomized controlled trials.

PURPOSE: Randomized controlled trials (RCTs) are suitable for meta-analysis and systematic reviews provided they are of high quality and are easy to retrieve. We determined these attributes of RCTs in obstetrical anaesthesia in a sample of available journals that are indexed in MEDLINE. SOURCE: Randomized controlled trials published between January 1985 and December 1994 in seven anaesthetic and three obstetric journals were identified by a MEDLINE search, and by handsearch of the same journals. Each RCT was assigned a quality score by a blinded rater using a reliable and validated scaled. The quality of each RCT was described and compared over time and by journal. The comparative yield of MEDLINE and hand-search was evaluated. PRINCIPAL FINDINGS: Three hundred and forty RCTs were retrieved by MEDLINE and handsearch. Two hundred and twenty seven (65%) were identified by the MEDLINE search and 333 by the handsearch (98%). The median quality score was 3/5. There was no difference in score over time. Anesthesiology had the highest median score, Anaesthesia had the lowest (P < 0.05). CONCLUSIONS: Care must be taken when reviewing obstetrical anaesthesia research. Strategies in addition to a MEDLINE search must be used to identify RCTs since more than one third were missed using MEDLINE alone. Poor quality RCTs are more likely to be biased in favour of a new treatment. Therefore, to increase the validity of reviews sensitivity analyses based on quality should be done.

Anesthesia, Obstetrical↗
PubMed2006

A primer on randomized controlled trials.

Randomized Clinical Trials are held as the gold standard for quantifying the effect of an intervention across two or more groups. In such a trial an intervention is randomly allocated to one of two groups. The benefit of such a trial lies in its ability to establish nearly comparable groups of subjects in all manner except for the effect of the intervention. As such, the effect of a given intervention may be attributed solely to the intervention and not to any other extraneous factor. In the following editorial, we will discuss several issues that are important for understanding how to conduct and interpret randomized trials: choosing the study population, choosing the comparison group, choosing your outcome, study design, data analysis, and issues of inference. This editorial is intended to make the reader an educated consumer of such trial designs.

Data Interpretation, Statistical↗
PubMed2006

Prostate cancer screening decreases the absolute risk of being diagnosed with advanced prostate cancer--results from a prospective, population-based randomized controlled trial.

OBJECTIVES: Randomized controlled trials are currently conducted to assess whether the mortality from prostate cancer is reduced by early detection with the use of prostate-specific antigen (PSA) measurements in serum. To be effective, such a program should be able to reduce the absolute number of men diagnosed with metastatic prostate cancer (for which no cure is available). The aim of the present report is to evaluate whether PSA-based screening reduces the risk of being diagnosed with metastatic prostate cancer. METHODS: A population-based, prospective, randomized, controlled screening trial for prostate cancer started in 1995 (the Göteborg branch of the European Randomized Study of Screening for Prostate Cancer [ERSPC]). Ten thousand, randomly selected men aged 50-66 yr were invited for biennial PSA testing, with 10,000 men serving as passive controls for whom diagnosis of metastatic prostate cancer was monitored by using the Swedish Cancer Registry. RESULTS: After a follow-up of 10 yr, the risk of being diagnosed with metastatic prostate cancer was reduced by 48.9%-that is, decreasing from 47 cases in the control group to 24 cases in the group randomized to PSA-based screening (p=0.0084). However, the risk of being diagnosed with prostate cancer increased 1.8-fold with PSA-based screening. CONCLUSIONS: Biennial PSA screening reduces the risk of being diagnosed with metastatic prostate cancer, the first prerequisite for achieving decreased cancer mortality in younger men. This putative benefit is balanced by a 1.8-fold increased risk for diagnosis of prostate cancer.

Aged↗
PubMed1990

Magnesium sulphate versus diazepam in the management of eclampsia: a randomized controlled trial.

This randomized controlled trial compared the use of magnesium sulphate with diazepam as anticonvulsant in 51 eclamptic women. The use of magnesium sulphate was associated with less serious morbidity (in terms of recurrence of convulsions, cardiopulmonary problems, disseminated intravascular coagulopathy, and acute renal failure) but the difference was not statistically significant (relative risk 0.6; 95% CI 0.3 to 1.2). The one maternal death occurred in the magnesium sulphate group. Convulsions recurred in five (21%) women in the magnesium sulphate group and seven (26%) women in the diazepam group. Urine output poor enough to prompt diuretic stimulation was less frequent in the magnesium sulphate group than in the diazepam group (RR 0.3; 95% CI 0.1 to 0.9). Significantly fewer infants born in the magnesium sulphate group had low Apgar scores (less than 7 at 1 min) compared with those in the diazepam group (RR 0.6; 95% CI 0.4 to 0.9). There were two early neonatal deaths in the magnesium sulphate group, and three stillbirths in the diazepam group. This study suggests that magnesium sulphate has advantages over diazepam for the mother and the infant in the treatment of eclampsia, but the trial is small and should be replicated on a larger scale.

Apgar Score↗
PubMed1997

Rationale, objectives, and interpretation of randomized controlled trials.

A randomized controlled trial (RCT) is the most definitive tool for evaluation of the effectiveness of an intervention and can establish a cause-and-effect relationship between an intervention and an improved disease outcome. However, the undertaking of an RCT does not guarantee valid results, and the findings of RCTs of the same intervention are often discrepant. While many reported trials are of high quality, a significant number have deficiencies in design, conduct, analysis, or interpretation of results. Medical practitioners must become familiar with the methodology of RCTs in order to assess the validity of the reported findings and the relevance of the results to their own patients. Trialists must report sufficient information about the methods used so that readers can judge for themselves if the trial worked as planned.

Education, Medical↗