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Results for “Randomized trial”

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PubMed2005

Intraclass correlation coefficients for cluster randomized trials in primary care: the cholesterol education and research trial (CEART).

Cluster randomization trials are increasingly being used in primary care research. The main feature of these trials is that patients are nested within large clusters such as physician practices or communities and the intervention is applied to the cluster. This study design necessitates calculation of intraclass correlation coefficients in order to determine the required sample size. The purpose of this study is to determine intraclass correlation coefficients for a number of outcome measures at the primary care practice level. The CEART study is a randomized trial testing the effectiveness of translating ATP III guidelines into clinical practice, with primary care physician practices as the unit of randomization and patients as the unit of data collection. The intraclass correlation coefficient (ICC) was<0.02 and the design effect ranged from 1.0 to 2.3, respectively, for weight, total cholesterol, LDL, non-HDL, glucose, creatinine, and % at non-HDL goal. For smoking status, body mass index, systolic blood pressure, HDL cholesterol triglycerides, total cholesterol/HDL ratio and % at LDL goal, the ICC was 0.02-0.047 and the design effect was 2.6-4.1. The largest ICCs (0.05-0.12) and design effects (4.4-9.4) were found for height and diastolic blood pressure. These findings suggest that cluster randomization may substantially increase the sample size necessary to maintain adequate statistical power for selected outcomes such as diastolic blood pressure studies compared with simple randomization for most outcomes evaluated in this study where the design effect is small to moderate. Overall, the ICCs presented will be useful in calculating sample sizes at the primary care level.

Adult↗

PubMed1981

Cimetidine and antacid prophylaxis of acute upper gastrointestinal bleeding in high risk patients. Controlled, randomized trial.

A randomized, controlled clinical trial was performed to compare the efficacy of prophylactic cimetidine treatment, antacid treatment and no treatment in high risk patients. Sixty patients received cimetidine (200 mg every 6 hours), 52 patients received antacids (Maalox, 10 ml/hour), and 56 patients received no treatment. One hundred thirty-five patients completed the study. Eight patients in the control group and one patient in the antacid-treated group presented with upper gastrointestinal bleeding. No bleeding occurred in the cimetidine-treated group. Patients considered at low risk had no bleeding. Cimetidine or antacid prophylaxis significantly decreased the incidence of upper gastrointestinal bleeding in the high risk patients.

Antacids↗

PubMed2000

Promotion of breastfeeding intervention trial (PROBIT): a cluster-randomized trial in the Republic of Belarus. Design, follow-up, and data validation.

This paper summarizes the objectives, design, follow-up, and data validation of a cluster-randomized trial of a breastfeeding promotion intervention modeled on the WHO/UNICEF Baby-Friendly Hospital Initiative (BFHI). Thirty-four hospitals and their affiliated polyclinics in the Republic of Belarus were randomized to receive BFHI training of medical, midwifery, and nursing staffs (experimental group) or to continue their routine practices (control group). All breastfeeding mother-infant dyads were considered eligible for inclusion in the study if the infant was singleton, born at > or = 37 weeks gestation, weighed > or = 2500 grams at birth, and had a 5-minute Apgar score > or = 5, and neither mother nor infant had a medical condition for which breastfeeding was contraindicated. One experimental and one control site refused to accept their randomized allocation and dropped out of the trial. A total of 17,795 mothers were recruited at the 32 remaining sites, and their infants were followed up at 1, 2, 3, 6, 9, and 12 months of age. To our knowledge, this is the largest randomized trial ever undertaken in area of human milk and lactation. Monitoring visits of all experimental and control maternity hospitals and polyclinics were undertaken prior to recruitment and twice more during recruitment and follow-up to ensure compliance with the randomized allocation. Major study outcomes include the occurrence of > or = 1 episode of gastrointestinal infection, > or = 2 respiratory infections, and the duration of breastfeeding, and are analyzed according to randomized allocation ("intention to treat"). One of the 32 remaining study sites was dropped from the trial because of apparently falsified follow-up data, as suggested by an unrealistically low incidence of infection and unrealistically long duration of breastfeeding, and as confirmed by subsequent data audit of polyclinic charts and interviews with mothers of 64 randomly-selected study infants at the site. Smaller random audits at each of the remaining sites showed extremely high concordance between the PROBIT data forms and both the polyclinic charts and maternal interviews, with no evident difference in under- or over-reporting in experimental vs control sites. Of the 17,046 infants recruited from the 31 participating study sites, 16,491 (96.7%) completed the study and only 555 (3.3%) were lost to follow-up. PROBIT's results should help inform decision-making for clinicians, hospitals, industry, and governments concerning the support, protection, and promotion of breastfeeding.

Adult↗

PubMed1989

Mechanical prophylaxis of venous thrombosis in patients undergoing craniotomy: a randomized trial.

A randomized, prospective clinical trial of 70 patients undergoing craniotomy was performed to compare and evaluate two forms of mechanical prophylaxis of deep vein thrombosis. Thirty-eight patients received antiembolism stockings, whereas 32 patients received external pneumatic compression. Prophylaxis was begun preoperatively and continued intraoperatively and post-operatively until the patients were ambulatory. Impedance plethysmography was used to detect deep vein thrombosis both preoperatively and postoperatively. Two patients, one from each group, developed thromboembolic complications postoperatively. Impedance plethysmography showed false-positive findings in two additional patients. There were no deaths. The data suggest that either form of mechanical prophylaxis is effective against the development of deep vein thrombosis in this high-risk patient population.

Clinical Trials as Topic↗

PubMedDate not supplied

Postoperative concurrent chemoradiotherapy with mitomycin in advanced squamous cell carcinoma of the head and neck: results from three prospective randomized trials.

UNLABELLED: Recent prospective randomized trials have shown concurrent chemoradiotherapy improves locoregional control in postoperative patients with squamous cell carcinoma of the head and neck using cisplatin-based regimes. This report presents data pooled from three randomized trials employing mitomycin, selecting those patients treated postoperatively, to evaluate the long-term benefit of mitomycin in the postoperative setting and to compare these results with those of two other recently published randomized trials. METHODS AND MATERIALS: Between 1980 and 1999, a total of 331 patients with squamous cell carcinoma of the head and neck from the three prospective trials were enrolled. Of the 205 postoperative patients in these trials, 103 were randomized to receive mitomycin and radiation, while 102 received radiation alone or radiation with porfiromycin in the third trial. Patients were treated with standard daily radiotherapy to a total median dose of 60 Gy over 47 days. Patients who were randomized to mitomycin C received 15 mg/m2 of the drug on days 5 and 47 (or last day). RESULTS: The 5-year rate of locoregional control was higher in the mitomycin arms. There was no statistically significant difference in the rates of overall survival or distant metastasis. Patients had a lower percentage of high-risk factors in both arms of the study, compared with patients in the large prospective trials, including positive margins, two or more positive lymph nodes, or oropharynx primary tumors. The gains in locoregional control realized with mitomycin were similar to the improvements in the recently published randomized trials using platinum. CONCLUSIONS: These results confirm significant gains in locoregional control using concurrent chemoradiotherapy in the postoperative setting for patients with squamous cell carcinoma of the head and neck. The lack of consensus over a benefit in the rates of overall survival and distant metastasis emphasizes the need for further prospective trials in the postoperative management of squamous cell carcinoma of the head and neck.

Antibiotics, Antineoplastic↗

PubMed2003

The Trial Bank system: capturing randomized trials for evidence-based medicine.

Randomized controlled trials (RCTs) are one of the best sources of evidence for the scientific practice of medicine. However, RCT findings are published only as text articles that are of limited machine understandability. The Trial Bank system captures information about the design, execution, and summary results of RCTs into a structured electronic knowledge base called RCT Bank.

Artificial Intelligence↗

PubMed2004

Mounting a community-randomized trial: sample size, matching, selection, and randomization issues in PRISM.

This paper discusses some of the processes for establishing a large cluster-randomized trial of a community and primary care intervention in 16 local government areas in Victoria, Australia. The development of the trial in terms of design factors such as sample size estimates and the selection and randomization of communities to intervention or comparison is described. The intervention program to be implemented in Program of Resources, Information and Support for Mothers (PRISM) was conceived as a whole community approach to improving support for all mothers in the first 12 months after birth. A cluster-randomized trial was thus the design of choice from the outset. With a limited number of communities available, a matched-pair design with eight pairs was chosen. Sample size estimates, adjusting for the cluster randomization and the pair-matched design, showed that with eight pairs, on average, 800 women from each community would need to respond to provide sufficient power to determine a 3% reduction in the prevalence of maternal depression 6 months after birth-a reduction deemed to be a worthwhile impact of the intervention to be reliably detected at 80% power. The process of selecting suitable communities and matching them into pairs required careful collection of data on numbers of births, size of the local government areas (LGAs), and an assessment of the capacity of communities to implement the intervention. Ways of dealing with boundary issues associated with potential contamination are discussed. Methods for the selection of feasible configurations of sets of pairs and the ultimate allocation to intervention or comparison are provided in detail. Ultimately, all such studies are a balancing act between selecting the minimum number of communities to detect a meaningful outcome effect of an intervention and the maximum size budget and other resources allow.

Adult↗

PubMed2002

Role of antibiotic prophylaxis for wound infection in percutaneous endoscopic gastrostomy (PEG): result of a prospective double-blind randomized trial.

A randomized, double-blind, controlled trial was carried out to determine the value of antibiotic prophylaxis in the prevention of wound infection in percutaneous endoscopic gastrostomy (PEG) procedures. The wound was evaluated using ASEPSIS method and categorized as disturbance of healing, minor or major wound infection on the 7th day and the 28th day. The rate of infection including major wound infection was lower in the prophylaxis group of patients at both seven and 28 days.

Adult↗

PubMed1994

Single-dose cholecalciferol suppresses the winter increase in parathyroid hormone concentrations in healthy older men and women: a randomized trial.

A randomized double-blind controlled trial of a single oral dose of 2.5 mg (100,000 IU) cholecalciferol (vitamin D3) was conducted in the winter in 189 healthy free-living men and women aged 63-76 y. The mean baseline serum concentration for 25-hydroxyvitamin D was 34.5 nmol/L and for parathyroid hormone 3.18 pmol/L. After 5 wk, mean serum 25-hydroxyvitamin D concentrations were 60% higher in the treated than in the placebo group (P < 0.001). There was a 12% difference in parathyroid hormone concentrations in the treated compared with the placebo group (P < 0.001). No differences in serum calcium were seen. Findings suggest that 25-hydroxyvitamin D has a physiological role in the regulation of parathyroid secretion independent of serum calcium in healthy elderly people. Parathyroid concentrations rise and 25-hydroxyvitamin D concentrations decline with age. These results may have implications for the prevention of osteoporotic fractures that occur with increased frequency in winter and in elderly people.

Aged↗

PubMed2002

Cluster-randomized trials.

Cluster-randomized trials represent an important experimental design, supplementing ordinary randomized clinical trials. They are particularly relevant when evaluating interventions at the level of clinic, hospital, district or region. They are necessary when it is not feasible to randomize individual patients, and desirable when there may be contamination between clusters. But they also carry serious design and analysis implications, and the use of clusters as the unit of randomization must be justified. Sample sizes will usually need to be greatly increased, an adequate number of clusters is essential, and the statistical analysis must allow for the cluster design. And one should rigorously guard against selection bias.

Bias↗

PubMed1996

Three-year follow-up of the Argentine Randomized Trial of Percutaneous Transluminal Coronary Angioplasty Versus Coronary Artery Bypass Surgery in Multivessel Disease (ERACI).

OBJECTIVES: The purpose of this study was to report the 3-year follow-up results of the ERACI trial (Argentine Randomized Trial of Percutaneous Transluminal Coronary Angioplasty Versus Coronary Artery Bypass Surgery in Multivessel Disease). BACKGROUND: Although coronary angioplasty has been used with increased frequency in patients with multivessel coronary artery disease, its value, compared with bypass graft surgery, has not been established. Thus, controlled, randomized clinical trials such as the ERACI are needed. METHODS: In this trial 127 patients who had multivessel coronary artery disease and clinical indication of myocardial revascularization were randomized to undergo coronary angioplasty (n = 63) or bypass surgery (n = 64). The primary end point of this study was event-free survival (survival with freedom from myocardial infarction, angina and new revascularization procedures) for both groups of patients at 1, 3 and 5 years of follow-up. RESULTS: Freedom from combined cardiac events (death, Q-wave myocardial infarction, angina and repeat revascularization procedures) was significantly greater for the bypass surgery group than the coronary angioplasty group (77% vs. 47%; p < 0.001). There were no differences in overall (4.7% vs. 9.5%; p = 0.5) and cardiac (4.7% vs. 4.7%; p = 1) mortality or in the frequency of myocardial infarction (7.8% vs. 7.8%; p = 0.8) between the two groups. However, patients who had bypass surgery were more frequently free of angina (79% vs. 57%; p < 0.001) and required fewer additional reinterventions (6.3% vs. 37%; p < 0.001) than patients who had coronary angioplasty. CONCLUSIONS: 1) Freedom from combined cardiac events at 3-year follow-up was greater in patients who had bypass surgery than in those who had coronary angioplasty. 2) The coronary angioplasty group had a higher incidence of recurrence of angina and the need for repeat revascularization procedures. 3) Cumulative cost at 3-year follow-up was greater for the bypass surgery group than for the coronary angioplasty group.

Angioplasty, Balloon, Coronary↗

PubMed2006

Sample size for cluster randomized trials: effect of coefficient of variation of cluster size and analysis method.

BACKGROUND: Cluster randomized trials are increasingly popular. In many of these trials, cluster sizes are unequal. This can affect trial power, but standard sample size formulae for these trials ignore this. Previous studies addressing this issue have mostly focused on continuous outcomes or methods that are sometimes difficult to use in practice. METHODS: We show how a simple formula can be used to judge the possible effect of unequal cluster sizes for various types of analyses and both continuous and binary outcomes. We explore the practical estimation of the coefficient of variation of cluster size required in this formula and demonstrate the formula's performance for a hypothetical but typical trial randomizing UK general practices. RESULTS: The simple formula provides a good estimate of sample size requirements for trials analysed using cluster-level analyses weighting by cluster size and a conservative estimate for other types of analyses. For trials randomizing UK general practices the coefficient of variation of cluster size depends on variation in practice list size, variation in incidence or prevalence of the medical condition under examination, and practice and patient recruitment strategies, and for many trials is expected to be approximately 0.65. Individual-level analyses can be noticeably more efficient than some cluster-level analyses in this context. CONCLUSIONS: When the coefficient of variation is <0.23, the effect of adjustment for variable cluster size on sample size is negligible. Most trials randomizing UK general practices and many other cluster randomized trials should account for variable cluster size in their sample size calculations.

Cluster Analysis↗

PubMed2002

Trillium-coated oxygenators in adult open-heart surgery: a prospective randomized trial.

This randomized, prospective clinical trial examines the impact of the use of Trillium biopassive surface coating on clinical outcomes after cardiopulmonary bypass (CPB) that may be induced by contact of blood elements with foreign surfaces. The study consisted of 98 consecutive patients randomly assigned to either a CPB circuit that consisted of a Trillium-coated Affinity open reservoir oxygenator or a CPB circuit with an uncoated Affinity open reservoir oxygenator. The operative procedure performed on all 98 patients consisted of either coronary artery bypass graft (CABG), valve, or a combination of the two. Exclusion criteria consisted of patients who presented to the operating room in circulatory arrest. Trillium biopassive surface coating resulted in improved clinical outcomes and fewer adverse events when compared to the control group. Significantly, fewer patients required no blood products (18.3% in the control group vs. 32.7% in the treatment group), even though the control group had a significantly higher pre-bypass hematocrit. Postoperative atrial fibrillation (24.5% vs. 16.3%) and reoperation for bleeding (10.2% vs. 4.1%) showed a much lower incidence in the Trillium group. Significance was not reached because of the small sample size resulting in low power. Trillium circuits result in improved patient outcomes in the treatment group when compared to the control circuit group.

Aged↗

PubMed2006

Epidemiology and reporting of randomized trials employing re-randomization of patient groups: a systematic survey.

Trials employing re-randomization of some or all participants provide opportunities for determining optimal dosing and dosing schedules, potential disease modifying effects, direct comparisons between drugs, and salvage therapy for patients failing their assigned treatments. To date, no data exists about their prevalence, epidemiology, or quality. We undertook a systematic review of all trials re-randomizing patients. Using explicit search criteria, we searched 11 electronic databases independently, in duplicate. We additionally searched pharmaceutical company websites for unpublished studies. We extracted data on the epidemiology of trials, year published, characteristics of the purpose of the re-randomization, what groups of patients were re-randomized, and methodological issues, including allocation, concealment, sequence generation, blinding, intention to treat, and appropriate sample size calculations. We found 65 trials. All trials were reported in English. Of these, 21 employed re-randomization to determine optimal dosing, 8 for optimal dose-scheduling, 3 for salvage therapy, 0 for estimating disease modifying effects, 24 as direct comparison trials, 9 as standard efficacy trials--that did not require re-randomization, and 3 as withdrawal of treatment trials. The median sample size of the period prior to re-randomization is 180 [interquartile range (IQR) 83-480] and after re-randomization is 104 [IQR 36 to 246]. Studies lost a median of 8% of eligible patients from period 1 to period 2 [IQR 0 to 17]. Studies were published between 1975 and 2005, with the vast majority (71%) published since 1995. The findings of our review indicate that trials employing re-randomization are relatively rare, have poor reporting of important methodological features, and, in some circumstances, fail to take advantage of the benefits that re-randomization can permit.

Dose-Response Relationship, Drug↗

PubMed2005

Stapled hemorrhoidopexy vs. Harmonic Scalpel hemorrhoidectomy: a randomized trial.

PURPOSE: A randomized trial was undertaken to evaluate and compare stapled hemorrhoidopexy with excisional hemorrhoidectomy in which the Harmonic Scalpel was used. METHODS: Patients with Grade III hemorrhoids who were employed during the trial period were recruited and randomized into two groups: (1) Harmonic Scalpel hemorrhoidectomy, and (2) stapled hemorrhoidopexy. All operations were performed by a single surgeon. In the stapled group, the doughnut obtained was sent for histopathologic examination to determine whether smooth muscles were included in the specimen. Operative data and complications were recorded, and patients were followed up through a structured pro forma protocol. An independent assessor was assigned to obtain postoperative pain scores and satisfaction scores at six-month follow-up. Patients were also administered a simple questionnaire at follow-up to assess continence functions. RESULTS: Over a 20-month period, 88 patients were recruited. The two groups were matched for age and gender distribution. No significant difference was identified between the two groups in terms of operation time, blood loss, day of first bowel movement after surgery, and complication rates. Despite a similar parenteral and oral analgesic requirement, the stapled group had a significantly better pain score (P = 0.002); these patients also had a significantly shorter length of stay (P = 0.02), and on average resumed work nine days earlier than the group treated with the Harmonic Scalpel (6.7 vs. 15.6, P = 0.002). Although 88 percent of doughnuts obtained in the stapled group contained some smooth muscle fibers, no association was found between smooth muscle incorporation and postoperative continence function, and as a whole the continence outcomes of the stapled group were similar to those after Harmonic Scalpel hemorrhoidectomy. Finally, at six-month follow-up, patients who underwent the stapled procedure had significantly better satisfaction scores (P = 0.001). CONCLUSION: Stapled hemorrhoidopexy is a safe and effective procedure for Grade III hemorrhoidal disease. Patients derive greater short-term benefits of reduced pain, shorter length of stay, and earlier resumption to work. Long-term follow-up is necessary to determine whether these initial results are lasting.

Absenteeism↗

PubMed1999

The effect of protein restriction on albuminuria in patients with type 2 diabetes mellitus: a randomized trial.

BACKGROUND: A randomized trial was conducted to assess whether protein restriction helps to delay the onset of renal disorders in type 2 diabetic patients. METHODS: Included in the trial were 121 type 2 diabetic patients with microalbuminuria or at least detectable albuminuria, or diabetes of duration > or =5 years. The experimental (39 male/19 female) and control group (35 male/28 female) received counselling on protein restriction and the usual dietary advice, respectively. The outcome measure was albuminuria (mg/24 h). Results. After 6 months in experimental and control groups the change in protein intake was -0.05+/-0.21 and +0.03+/-0.19 g/kg (P = 0.02), and in albuminuria -14% and +11% (P = 0.01), respectively. After 12 months, the differences between the experimental and the control group with respect to both protein intake and albuminuria had decreased. At 6 and 12 months, respectively, albuminuria was 28% (P<0.001) and 18% (P = 0.08) lower in the experimental than the control group. The effect in normoalbuminuric patients did not differ from that in microalbuminuric patients. In the experimental group, blood pressure, HbA1c and body weight decreased; in the control group, such decreases were less or absent. Dose-response analysis showed that a 0.10 g/kg change at 6 months in the intake of protein, of animal protein in particular, was related to an 11.1% change in albuminuria (P<0.005). Combining the intakes at 6 and 12 months suggested a percentage change of 9.1%. CONCLUSIONS: Substantial protein restriction in primary care, type 2 diabetic patients with no nephropathy is barely feasible. However, even a small reduction has a substantial and potentially beneficial effect on albuminuria.

Adult↗

PubMed2004

Phase II randomized trial of autologous formalin-fixed tumor vaccine for postsurgical recurrence of hepatocellular carcinoma.

PURPOSE: We conducted a Phase II clinical trial with randomized patients to determine whether autologous formalin-fixed tumor vaccine (AFTV) protects against postsurgical recurrence of hepatocellular carcinoma (HCC). EXPERIMENTAL DESIGN: Forty-one patients with HCC who had undergone curative resection were randomly allocated to the vaccine treatment (n = 19) or no adjuvant control group (n = 22). Three intradermal vaccinations were administered at 2-week intervals beginning 4-6 weeks after hepatic resection. A delayed-type hypersensitivity test was performed before and after vaccination. Primary and secondary end points are recurrence-free survival and overall survival, respectively. Observation continued until the majority of surviving patients had lived >12 months after the curative resection. RESULTS: In a median follow-up of 15 months, the risk of recurrence in vaccinated patients was reduced by 81% (95% confidence interval, 33-95%; P = 0.003). Vaccination significantly prolonged the time to first recurrence (P = 0.003) and improved recurrence-free survival (P = 0.003) and overall survival rates (P = 0.01). AFTV played a significant role in preventing recurrence in patients with small tumors. Adverse effects were limited to grade 1 or 2 skin toxicities such as erythema, dry desquamation, and pruritus. CONCLUSIONS: AFTV therapy is a safe, feasible, and effective treatment for preventing postoperational recurrence of HCC. Patients with low tumor burdens benefit from the treatment. This treatment should be advanced to a large-scale randomized trial.

Aged↗

PubMed1986

Intratumoral Bacillus Calmette-Guérin immunotherapy prior to surgery for carcinoma of the lung: results of a prospective randomized trial.

A prospective randomized trial of preoperative intratumoral therapy with Bacillus Calmette-Guérin (BCG) was conducted in non-small cell lung cancer patients. Eighty-eight patients (48 BCG-treated and 40 control subjects) were entered into the study; three control subjects were removed from data analysis because histology revealed pathology other than non-small cell lung cancer. There were no differences between BCG-treated and control patients in sex, age, cigarettes smoked per day, pack-years of cigarette smoking, white blood cell count, or number of peripheral blood lymphocytes. Toxicity of BCG was limited to transient malaise and fever (average peak temperature, 38.7 degrees C). There was no significant difference in outcome (recurrence or survival) between BCG-treated and control groups with Stage I or Stage III tumors; there were too few Stage II tumors for separate statistical analysis. Outcome was not affected within or between the two treatment groups by tuberculin skin test status. Combining both treatment groups, Stage III patients had a worse outcome than did Stage I-II patients, non-squamous cell tumor patients (large cell and adenocarcinoma) had worse outcomes than did squamous cell tumor patients, and men had a worse outcome than women. We conclude that, although preoperative intratumoral BCG therapy is safe, it does not lengthen disease-free interval or prolong survival in patients with non-small cell lung cancer.

Bacterial Vaccines↗