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Results for “Randomized controlled trials”

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At least 487 records · Page 27Linked to original sources

PubMed2006

Effect of folic acid supplementation on risk of cardiovascular diseases: a meta-analysis of randomized controlled trials.

CONTEXT: Epidemiologic studies have suggested that folate intake decreases risk of cardiovascular diseases. However, the results of randomized controlled trials on dietary supplementation with folic acid to date have been inconsistent. OBJECTIVE: To evaluate the effects of folic acid supplementation on risk of cardiovascular diseases and all-cause mortality in randomized controlled trials among persons with preexisting cardiovascular or renal disease. DATA SOURCES: Studies were retrieved by searching MEDLINE (January 1966-July 2006) using the Medical Subject Headings cardiovascular disease, coronary disease, coronary thrombosis, myocardial ischemia, coronary stenosis, coronary restenosis, cerebrovascular accident, randomized controlled trial, clinical trials, homofolic acid, and folic acid, and the text words folic acid and folate. Bibliographies of all retrieved articles were also searched, and experts in the field were contacted. STUDY SELECTION: From 165 relevant retrieved reports, 12 randomized controlled trials compared folic acid supplementation with either placebo or usual care for a minimum duration of 6 months and with clinical cardiovascular disease events reported as an end point. DATA EXTRACTION: Data on study design, characteristics of participants, changes in homocysteine levels, and cardiovascular disease outcomes were independently abstracted by 2 investigators using a standardized protocol. DATA SYNTHESIS: Studies including data from 16 958 participants with preexisting vascular disease were analyzed using a random-effects model. The overall relative risks (95% confidence intervals) of outcomes for patients treated with folic acid supplementation compared with controls were 0.95 (0.88-1.03) for cardiovascular diseases, 1.04 (0.92-1.17) for coronary heart disease, 0.86 (0.71-1.04) for stroke, and 0.96 (0.88-1.04) for all-cause mortality. The relative risk was consistent among participants with preexisting cardiovascular or renal disease. CONCLUSIONS: Folic acid supplementation has not been shown to reduce risk of cardiovascular diseases or all-cause mortality among participants with prior history of vascular disease. Several ongoing trials with large sample sizes might provide a definitive answer to this important clinical and public health question.

Cardiovascular Diseases↗

PubMedDate not supplied

Assessing the validity of published randomized controlled trials in podiatric medical journals.

The purposes of this study were to develop an instrument to assess the validity of randomized controlled trials and to report on the differences in the validity of randomized controlled trials between two podiatric medical journals and a mainstream medical journal. The study demonstrated that after adequate training, there can be agreement among reviewers evaluating the quality of published randomized controlled trials using an established instrument and guidelines. The results of the study indicate that randomized controlled trials published in podiatric medical journals are less credible than those published in a mainstream medical journal.

Humans↗

PubMed1997

Discrepancies between meta-analyses and subsequent large randomized, controlled trials.

BACKGROUND: Meta-analyses are now widely used to provide evidence to support clinical strategies. However, large randomized, controlled trials are considered the gold standard in evaluating the efficacy of clinical interventions. METHODS: We compared the results of large randomized, controlled trials (involving 1000 patients or more) that were published in four journals (the New England Journal of Medicine, the Lancet, the Annals of Internal Medicine, and the Journal of the American Medical Association) with the results of meta-analyses published earlier on the same topics. Regarding the principal and secondary outcomes, we judged whether the findings of the randomized trials agreed with those of the corresponding meta-analyses, and we determined whether the study results were positive (indicating that treatment improved the outcome) or negative (indicating that the outcome with treatment was the same or worse than without it) at the conventional level of statistical significance (P<0.05). RESULTS: We identified 12 large randomized, controlled trials and 19 meta-analyses addressing the same questions. For a total of 40 primary and secondary outcomes, agreement between the meta-analyses and the large clinical trials was only fair (kappa= 0.35; 95 percent confidence interval, 0.06 to 0.64). The positive predictive value of the meta-analyses was 68 percent, and the negative predictive value 67 percent. However, the difference in point estimates between the randomized trials and the meta-analyses was statistically significant for only 5 of the 40 comparisons (12 percent). Furthermore, in each case of disagreement a statistically significant effect of treatment was found by one method, whereas no statistically significant effect was found by the other. CONCLUSIONS: The outcomes of the 12 large randomized, controlled trials that we studied were not predicted accurately 35 percent of the time by the meta-analyses published previously on the same topics.

Humans↗

PubMed1989

Succinylcholine and atropine for premedication of the newborn infant before nasotracheal intubation: a randomized, controlled trial.

Twenty preterm newborn infants were randomized to receive either atropine alone (20 micrograms/kg) or atropine plus succinylcholine (2 mg/kg) before nasotracheal intubation. Heart rate, BP, transcutaneous PO2, and intracranial pressure were monitored continuously before, during, and after intubation. No infants developed bradycardia or hypoxia. Intracranial hypertension developed during intubation in the infants receiving atropine alone, but was prevented by premedication with succinylcholine and atropine (p less than .01). A 41% increase in systemic BP occurred immediately after the administration of succinylcholine (p less than .01). BP increased during intubation in both groups, and the overall peak BP was not significantly different between the groups. Intubation was significantly shorter in the infants receiving succinylcholine. Premedication with succinylcholine and atropine will facilitate intubation of neonates, and ameliorate the adverse physiologic consequences of this procedure.

Atropine↗

PubMed1999

Comparing outcomes of percutaneous transluminal coronary angioplasty with coronary artery bypass grafting; can routine health service data complement and enhance randomized controlled trials?

AIM: To compare outcomes of percutaneous transluminal coronary angioplasty (PTCA) with coronary artery bypass graft surgery (CABG) for a population stemming from routinely collected data, in order to assess the merits of such data sources as a complement, and possible enhancement, to randomized controlled trial results. METHODS AND RESULTS: A population of Scottish patients were taken from a routine discharge summary and from this data source patients comparable to those from randomized controlled trial settings were identified. Between 1989 and 1995, 12 238 pseudo randomized controlled trial patients were identified from the routine data set, of which 3714 (30.3%) received PTCA and 8524 (69.7%) received CABG. The baseline characteristics of the pseudo randomized controlled trial and randomized controlled trial patients were similar. The evidence from both the randomized controlled trials and routine data indicate that for 1 year follow-up the risk of cardiac death and/or non-fatal myocardial infarction is not significantly different between the two treatment groups. CONCLUSION: The outcomes expected of PTCA and CABG following trial evidence have been realized in the routine data which are representative of a complete, non-selective population. Due to the size of the routine data set it would be possible to set up hypotheses for potential subgroup effects at the outset.

Angioplasty, Balloon, Coronary↗

PubMed2006

Impact of new technologies on the clinical and functional outcome of Altemeier's procedure: a randomized, controlled trial.

PURPOSE: A randomized study was performed to assess whether new technologies offer advantages over the conventional technique on the clinical and functional outcome of patients with full-thickness rectal prolapse and fecal incontinence, submitted to Altemeier's procedure with levatorplasty. METHODS: Between January 1999 and December 2003, 58 patients (55 females; mean age, 70.9 +/- 11.3 years) with full-thickness rectal prolapse were evaluated with continence score, colonoscopy, anorectal manometry, anal electromyography, and sacral reflex latency; 40 of them were selected and randomly assigned to two groups: 20 patients (Group 1; 19 females, 73.4 +/- 10.4 years) were submitted to a conventional operation with monopolar electrocautery and handsewn anastomosis, and 20 (Group 2; 18 females, 71.5 +/- 12.2 years) using harmonic scalpel and circular stapler. Patients were followed up with clinical examination, anorectal manometry, and anal electromyography, with mean follow-up 29.3 +/- 8.5 and 27.5 +/- 9.2 months in Groups 1 and 2, respectively. RESULTS: Operative time, blood loss, and hospital stay were significantly reduced in Group 2 (P < 0.001), whereas no differences were found in pain score, time to return to normal activity, morbidity, and mortality. Complications were two (10 percent) stenosis in Group 1. Fecal continence score significantly improved in both groups (P < 0.01), whereas anorectal manometry and neurophysiologic data were not significantly modified by the operation. Recurrence rates were 15 and 10 percent in Groups 1 and 2, respectively (P= not significant). CONCLUSIONS: The clinical and functional long-term results of perineal rectosigmoidectomy with levatorplasty are not influenced by surgical instruments and type of coloanal anastomosis. The clinical relevance of the short-term results in high-risk patients should be specifically investigated.

Aged↗

PubMed2005

[Design and application of single case randomized controlled trial].

The principle, method, procedure, indicated subject and feasibility of application of single case randomized controlled trial (SCRCT) were reviewed in the article. In randomized controlled trials (RCT), the allocation unit can be a single case (random therapy), multiple cases (random allocation) or group such as family, class or community. Traditional Chinese medicine is good at treatment of chronic disease, Syndrome differentiation, the traits of TCM, requires multiple research methods. SCRCT is suitable for symptomatic treatment of chronic discase due to its convenience in observation, reduce individual divergence and low research cost. SCRCGT is characterized by using randomized method to carry out multiple crossover follow-up, to assess the efficacy of treatment for two therapeutic schemes.

Chronic Disease↗

PubMed2004

Randomized controlled trials on hepato-biliary-pancreatic surgery.

The randomized controlled trial (RCT) plays an important role not only in the performance of evidence-based medicine but also in the establishment of therapeutic guidelines. In this review, I analyzed RCTs on hepato-biliary-pancreatic surgery, particularly on malignant diseases. The number of RCTs on hepato-biliary-pancreatic cancers is smaller than that on other types of cancers. This might be related to their low resectability. In liver surgery, a recent increase in RCTs of operative techniques has almost established a standard transection method. In biliary tract and pancreatic cancers, only a few RCTs have been performed concerning operative strategy. Therefore, many issues should be solved by an adequate RCT observing statements of the Consolidated Standards of Reporting Trials.

Biliary Tract Neoplasms↗

PubMed2001

Cost effectiveness of periradicular infiltration for sciatica: subgroup analysis of a randomized controlled trial.

STUDY DESIGN: A subgroup analysis of a prospective, randomized controlled trial was performed. OBJECTIVE: To describe the cost effectiveness of periradicular infiltration with steroid in subgroups of patients with sciatica. SUMMARY OF BACKGROUND DATA: A recent trial on periradicular infiltration indicated that a methylprednisolone-bupivacaine combination had a short-term effect, as compared with that of saline. This report describes the efficacy and cost effectiveness of steroid in subgroups of patients with sciatic. METHODS: This study involved 160 patients with unilateral sciatica. Outcome assessments were leg pain (100-mm visual analog scale), disability on the Oswestry Low Back Disability Questionnaire, and the Nottingham Health Profile. Data on medical costs and sick leaves also were gathered. Patients were randomized for periradicular infiltration with either methylprednisolone-bupivacaine or saline. The adjusted between-group treatment differences at each follow-up assessment, the number of patients free of leg pain (responders, cutoff 75%), and efficacy by the area-under-the-curve method were calculated. For the cost-effectiveness estimate, the total costs were divided by the number of responders. The rate of operations in different subgroups was evaluated by Kaplan-Meier analysis. RESULTS: In the case of contained herniations, the steroid injection produced significant treatment effects and short-term efficacy in leg pain and in Nottingham Health Profile emotional reactions. For symptomatic lesions at L3-L4-L5, steroid was superior to saline for leg pain, disability, and straight leg raising in the short term. By 1 year, steroid seemed to have prevented operations for contained herniations, costing $12,666 less per responder in the steroid group (P < 0.01). For extrusions, steroid seemed to increase the operation rate, and the steroid infiltration was more expensive, costing $4445 per responder (P < 0.01). CONCLUSIONS: In addition to short-term effectiveness for contained herniations and lesions at L3-L4-L5, steroid treatment also prevented surgery for contained herniations. However, steroid was countereffective for extrusions. The results of the subgroup analyses call for a verification study.

Adult↗

PubMed2001

How well is the clinical importance of study results reported? An assessment of randomized controlled trials.

BACKGROUND: The interpretation of the results of randomized controlled trials (RCTs) has traditionally emphasized statistical significance rather than clinical importance. Our aim was to assess the quality of reporting of factors related to clinical importance in a sample of published RCTs. METHODS: A random sample of 27 (of a total of 266) RCTs published in 5 major medical journals over a 1-year period were reviewed by 4 independent reviewers for factors considered important in the interpretation of the clinical importance of study results: identification of a clearly defined primary outcome, reporting of the expected difference between groups used in the calculation of sample size (the delta value) and whether it was based on the minimal clinically important difference of the intervention, the statistical significance of the results, presentation of pertinent confidence intervals, and the authors' interpretation of the clinical importance of the results. RESULTS: Twenty-two of 27 (81%) articles explicitly reported a single primary outcome. Of the 20 articles that included a sample size calculation, 18 (90%) reported a delta value. Two of the 18 (11%) articles explicitly stated that the delta value was chosen to reflect the minimal clinically important difference of the intervention. For the primary outcomes, confidence intervals surrounding the point estimates of the efficacy of the interventions were reported in 11 of 27 (41%) studies. The study results were interpreted from the perspective of clinical importance in 20 of 27 (74%) of the articles. Of these 20 reports, 5 (25%) provided justification for their clinical interpretation of the results. INTERPRETATION: Authors of RCTs published in major general medical and internal medicine journals do not consistently provide their own interpretation of the clinical importance of their results, and they often do not provide sufficient information to allow readers to make their own interpretation.

Periodicals as Topic↗

PubMed1990

Randomized, controlled trial of a 10-day course of amifloxacin versus trimethoprim-sulfamethoxazole in the treatment of acute, uncomplicated urinary tract infection. Amifloxacin Multi-Center Trial Group.

We conducted a randomized controlled trial of orally administered amifloxacin versus trimethoprimsulfamethoxazole (TMP-SMX) as treatments of acute uncomplicated urinary tract infection in women. Amifloxacin at a dosage of 200 mg twice a day appeared as safe and effective as TMP-SMX, but amifloxacin at 400 mg twice a day tended to cause adverse events more frequently than did TMP-SMX.

Administration, Oral↗

PubMed2006

Reporting of randomized controlled trials in Hodgkin lymphoma in biomedical journals.

BACKGROUND: Randomized controlled trials (RCTs) are the best tool to evaluate the effectiveness of clinical interventions. The Consolidated Standards for Reporting Trials (CONSORT) statement was introduced in 1996 to improve reporting of RCTs. We aimed to determine the extent of ambiguity and reporting quality as assessed by adherence to the CONSORT statement in published reports of RCTs involving patients with Hodgkin lymphoma from 1966 through 2002. METHODS: We analyzed 242 published full-text reports of RCTs in patients with Hodgkin lymphoma. Quality of reporting was assessed using a 14-item questionnaire based on the CONSORT checklist. Reporting was studied in two pre-CONSORT periods (1966-1988 and 1989-1995) and one post-CONSORT period (1996-2002). RESULTS: Only six of the 14 items were addressed in 75% or more of the studies in all three time periods. Most items that are necessary to assess the methodologic quality of a study were reported by fewer than 20% of the studies. Improvements over time were seen for some items, including the description of statistics methods used, reporting of primary research outcomes, performance of power calculations, method of randomization and concealment allocation, and having performed intention-to-treat analysis. CONCLUSIONS: Despite recent improvements, reporting levels of CONSORT items in RCTs involving patients with Hodgkin lymphoma remain unsatisfactory. Further concerted action by journal editors, learned societies, and medical schools is necessary to make authors even more aware of the need to improve the reporting RCTs in medical journals to allow assessment of validity of published clinical research.

Bibliometrics↗

PubMed2006

Prophylactic ilioinguinal neurectomy in open inguinal hernia repair: a double-blind randomized controlled trial.

OBJECTIVE: We conducted a double-blinded randomized controlled trial to investigate the short- to mid-term neurosensory effect of prophylactic ilioinguinal neurectomy during Lichtenstein repair of inguinal hernia. METHOD: One hundred male patients between the age of 18 and 80 years with unilateral inguinal hernia undergoing Lichtenstein hernia repair were randomized to receive either prophylactic ilioinguinal neurectomy (group A) or ilioinguinal nerve preservation (group B) during operation. All operations were performed by surgeons specialized in hernia repair under local anesthesia or general anesthesia. The primary outcome was the incidence of chronic groin pain at 6 months. Secondary outcomes included incidence of groin numbness, postoperative sensory loss or change at the groin region, and quality of life measurement assessed by SF-36 questionnaire at 6 months. All follow-up and outcome measures were carried out by a designated occupational therapist at 1 and 6 months following surgery in a double-blinded manner. RESULTS: The incidence of chronic groin pain at 6 months was significantly lower in group A than group B (8% vs. 28.6%; P = 0.008). No significant intergroup differences were found regarding the incidence of groin numbness, postoperative sensory loss or changes at the groin region, and quality of life measurement at 6 months after the operation. CONCLUSIONS: Prophylactic ilioinguinal neurectomy significantly decreases the incidence of chronic groin pain after Lichtenstein hernia repair without added morbidities. It should be considered as a routine surgical step during the operation.

Adolescent↗

PubMed2004

A randomized controlled trial of knifelight and open carpal tunnel release.

A randomized controlled trial was done to compare the results of carpal tunnel decompression using the standard open approach and the Knifelight technique. Twenty-six patients with bilateral carpal tunnel syndrome requiring operation were selected for the study and the operative technique was randomized for the first hand. Six weeks later, the second hand was operated upon using the alternate technique. There was little difference between the two techniques with regard to time taken to return to work, return of grip strength, symptom relief, complications, incidence of pillar pain and patient preference. However, the incidence of scar tenderness was significantly lower with the Knifelight technique.

Carpal Tunnel Syndrome↗

PubMed2002

Effect of aerobic exercise on blood pressure: a meta-analysis of randomized, controlled trials.

PURPOSE: Physical activity has been associated with reduced blood pressure in observational epidemiologic studies and individual clinical trials. This meta-analysis of randomized, controlled trials was conducted to determine the effect of aerobic exercise on blood pressure. DATA SOURCES: English-language articles published before September 2001. STUDY SELECTION: 54 randomized, controlled trials (2419 participants) whose intervention and control groups differed only in aerobic exercise. DATA EXTRACTION: Using a standardized protocol and data extraction form, three of the investigators independently abstracted data on study design, sample size, participant characteristics, type of intervention, follow-up duration, and treatment outcomes. DATA SYNTHESIS: In a random-effects model, data from each trial were pooled and weighted by the inverse of the total variance. Aerobic exercise was associated with a significant reduction in mean systolic and diastolic blood pressure (-3.84 mm Hg [95% CI, -4.97 to -2.72 mm Hg] and -2.58 mm Hg [CI, -3.35 to -1.81 mm Hg], respectively). A reduction in blood pressure was associated with aerobic exercise in hypertensive participants and normotensive participants and in overweight participants and normal-weight participants. CONCLUSIONS: Aerobic exercise reduces blood pressure in both hypertensive and normotensive persons. An increase in aerobic physical activity should be considered an important component of lifestyle modification for prevention and treatment of high blood pressure.

Adult↗

PubMed2006

Do randomized controlled trials always trump case reports? A second look at propranolol and depression.

STUDY OBJECTIVE: To explore reasons for discrepancies between findings from case reports and those from a meta-analysis of randomized controlled trials regarding the association between beta-adrenergic blockers and depression. DESIGN: Systematic review. DATA SOURCE: PubMed/MEDLINE database. MEASUREMENTS AND MAIN RESULTS: We reviewed 24 published case reports showing an association between beta-blockers and depression and eight randomized controlled trials included in a meta-analysis of the adverse effects of these drugs. We abstracted the beta-blocker taken, patients' age and sex, diagnoses, history of depression, type of depressive symptoms reported, and method and timing of the assessment of depression. Naranjo criteria were used to evaluate the strength of evidence from each case report for a possible association between beta-blockers and depression. Twelve case reports had a Naranjo score of 5 or more (suggesting a likely causal relationship), nine of which involved propranolol. In all nine, depression began soon after treatment, and in four, the patient had a history of depression. Three randomized controlled trials assessed propranolol. Depression rates in the control groups of these studies differed substantially from each other (0-40%, p<0.0001). In only one randomized controlled trial did investigators assess depression systematically; they evaluated depression after 1 year of treatment and eliminated patients who had previously been prescribed an antidepressant. CONCLUSION: A criterion standard to assess the true relationship between beta-blockers and depression is lacking. Factors such as the lack of systematic assessment of depression, the timing of assessments, and the selection of patients may have reduced the ability of researchers in the randomized controlled trials to detect depression as an adverse effect. Evidence from case reports should be carefully considered when relevant randomized controlled trials have not been adequately designed to detect adverse effects.

Adrenergic beta-Antagonists↗

PubMed2002

Using the Zelen design in randomized controlled trials: debates and controversies.

BACKGROUND: The use of the randomized consent design (commonly known as the Zelen design) is a controversial issue in randomized controlled trials. In the Zelen design, participants are randomly allocated prior to seeking consent. Those participants allocated to the intervention group are then approached and offered the intervention, which they can decline or accept. Zelen first proposed the design in 1979. It has been used infrequently since this time, although there are some notable exceptions in nursing, midwifery and some medical specialities. AIM: This paper describes the Zelen design, including the two forms used (the single and double consent versions) and discusses the advantages and disadvantages of using such a design. METHODS: An explanation of the differences between the Zelen design and a conventional randomized controlled trial is presented. In a conventional design, detailed knowledge of the alternative interventions is given to the prospective participant. The participant gives consent and is allocated to one of the groups. In a Zelen design, participants are randomly allocated and then approached and offered the group to which they were allocated. The Zelen design is used firstly, to reduce disappointment bias in the conventional consent-randomization process, and secondly, to remove subjective bias in the recruitment process. There are concerns relating to the use of the Zelen design, including ethical concerns relating to the timing of random allocation and consent and the collection of clinical data. CONCLUSION: It is hoped that by presenting issues pertaining to the Zelen design, other nursing and midwifery researchers may be prompted to consider its use when designing clinical research. The Zelen design is controversial, and debate about its merits and shortcomings is useful. This paper contributes to the ongoing debate.

Ethics, Nursing↗

PubMed2001

Meta-analyses in systematic reviews of randomized controlled trials in perinatal medicine: comparison of fixed and random effects models.

There is a need for empirical work comparing the random effects model with the fixed effects model in the calculation of a pooled relative risk in the meta-analysis in systematic reviews of randomized controlled trials. Such comparisons are particularly important when trial results are heterogeneous. We considered 84 independent meta-analyses in which each trial included a set of different women/newborns. These meta-analyses were included in systematic reviews published in the Cochrane Library's pregnancy and childbirth module. Twenty-one of these 84 meta-analyses demonstrated statistical heterogeneity at p<0.10. The random effects model estimates showed wider confidence intervals, particularly in those meta-analyses showing heterogeneity in the trial results. The summary relative risk for the random effects model tended to show a larger protective treatment effect than the fixed effects model in the heterogeneous meta-analyses. In this set of meta-analyses, statistical evaluation of publication bias cannot be shown to account for heterogeneity. Our empirical conclusion is that there may be opposing effects if the random effects model is used in the meta-analysis of clinical trials showing heterogeneity in the results: stronger treatment effects reflected in the summary relative risk, but wider confidence intervals about this summary measure.

Chi-Square Distribution↗