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Results for “randomised trial”

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PubMed2000

Optimum percutaneous transluminal coronary angioplasty compared with routine stent strategy trial (OPUS-1): a randomised trial.

BACKGROUND: Whether routine implantation of coronary stents is the best strategy to treat flow-limiting coronary stenoses is unclear. An alternative approach is to do balloon angioplasty and provisionally use stents only to treat suboptimum results. We did a multicentre trial to compare the outcomes of patients treated with these strategies. METHODS: We randomly assigned 479 patients undergoing single-vessel coronary angioplasty routine stent implantation or initial balloon angioplasty and provisional stenting. We followed up patients for 6 months to determine the composite rate of death, myocardial infarction, cardiac surgery, and target-vessel revascularisation. RESULTS: Stents were implanted in 227 (98.7%) of the patients assigned routine stenting. 93 (37%) patients assigned balloon angioplasty had at least one stent placed because of suboptimum angioplasty results. At 6 months the composite endpoint was significantly lower in the routine stent strategy (14 events, 6.1%) than with the strategy of balloon angioplasty with provisional stenting (37 events, 14.9%, p=0.003). The cost of the initial revascularisation procedure was higher than when a routine stent strategy was used (US$389 vs $339, p<0.001) but at 6 months, average per-patient hospital costs did not differ ($10,206 vs $10,490). Bootstrap replication of 6-month cost data showed continued economic benefit of the routine stent strategy. INTERPRETATION: Routine stent implantation leads to better acute and long-term clinical outcomes at a cost similar to that of initial balloon angioplasty with provisional stenting.

Adult↗

PubMed2000

Cluster randomised trials in maternal and child health: implications for power and sample size.

BACKGROUND: Interventions based in the community can be evaluated by randomising clusters, such as general practices, rather than individuals, as in conventional randomised trials. This increases the sample size needed because of intracluster correlation. AIMS: To estimate sample size requirements for cluster randomised trials of interventions based in general practice directed at common health problems affecting mothers and infants. METHODS: Data were collected from a pilot trial of the effect of Citizen's Advice Bureau services involving six general practices. Outcome measures included the Edinburgh postnatal depression score, the Warwick child health and morbidity profile, number of visits to the general practitioner, and two questionnaires delivered at the beginning and end of the study. Intracluster correlation coefficients and inflation factors (the ratio of the sample size required for a cluster randomised trial to that required for an individually randomised trial) were calculated. RESULTS: Intracluster correlation coefficients ranged from 0 (sleeping problems, accidental injury, hospitalisation) to 0.09 (maternal smoking), with most being < 0.04 (for example, maternal depression, breast feeding, general health, minor illness, behavioural problems, and visits to the general practitioner). Assuming 50 cases/practice, cluster randomised trials require sample sizes up to 3 times greater than individually randomised trials for most health outcomes measured. CONCLUSIONS: These data enable sample sizes to be estimated for cluster randomised trials into a range of maternal and child health outcomes. Using such a design, approximately 40 practices would be sufficient to evaluate the effect of an intervention on maternal depression, sleeping, and behavioural problems, and non-routine visits to the general practitioner.

Analysis of Variance↗

PubMedDate not supplied

Epidemiology and reporting of randomised trials published in PubMed journals.

Although randomised trials are important for evidence-based medicine, little is known about their overall characteristics. We assessed the epidemiology and reporting of methodological details for all 519 PubMed-indexed randomised trials published in December, 2000 (383 [74%] parallel-group, 116 [22%] crossover). 482 (93%) were published in specialty journals. A median of 80 participants (10th-90th percentile 25-369) were recruited for parallel-group trials. 309 (60%) were blinded. Power calculation, primary outcomes, random sequence generation, allocation concealment, and handling of attrition were each adequately described in less than half of publications. The small sample sizes are worrying, and poor reporting of methodological characteristics will prevent reliable quality assessment of many published trials.

Publishing↗

PubMed2006

Modelling multivariate outcomes in hierarchical data, with application to cluster randomised trials.

In the cluster randomised study design, the data collected have a hierarchical structure and often include multivariate outcomes. We present a flexible modelling strategy that permits several normally distributed outcomes to be analysed simultaneously, in which intervention effects as well as individual-level and cluster-level between-outcome correlations are estimated. This is implemented in a Bayesian framework which has several advantages over a classical approach, for example in providing credible intervals for functions of model parameters and in allowing informative priors for the intracluster correlation coefficients. In order to declare such informative prior distributions, and fit models in which the between-outcome covariance matrices are constrained, priors on parameters within the covariance matrices are required. Careful specification is necessary however, in order to maintain non-negative definiteness and symmetry between the different outcomes. We propose a novel solution in the case of three multivariate outcomes, and present a modified existing approach and novel alternative for four or more outcomes. The methods are applied to an example of a cluster randomised trial in the prevention of coronary heart disease. The modelling strategy presented would also be useful in other situations involving hierarchical multivariate outcomes.

Artificial Intelligence↗

PubMed1994

A comparison of early effects with two dose rates in brachytherapy of cervix carcinoma in a prospective randomised trial.

This phase III randomised trial examined the early effects of two low dose rates (0.38 and 0.73 Gy/h) in brachytherapy of stage I and IIp cervical cancer patients. A total of 204 patients were included between January 1985 and September 1988. Since the main analysis of this paper concerned surgical difficulties, only the 155 patients (76%) on whom surgery was performed at the Institut Gustave-Roussy were retained in this analysis. Treatment consisted of uterovaginal 137Cs irradiation followed by immediate or deferred surgery. The two groups were similar for pretreatment characteristics except for endocervix involvement. Their brachytherapy parameters were also similar (60 Gy pear dimensions, doses to critical organs, total kerma, etc.). The factors with a poor prognosis were, for surgical difficulties, older age, stage II and a small irradiated pear volume; for difficulties with haemostasis, immediate surgery, stage II and previous surgery; and for difficulties in dissection, lymph node involvement. The dose rate significantly influenced surgical difficulties for the stage IIp patients operated on by deferred surgery. Those treated with the higher dose rate showed a 2-fold increase in surgical difficulties compared to those irradiated at the lower dose rate (P = 0.03). The independent prognostic factors for sterilisation of the surgical specimen were small tumour size and absence of lymph node involvement. An inverse dose rate effect was observed for medium size tumours, with significantly more sterilisations observed in stage IIp patients in the lower dose rate group (P < 0.01).

Adult↗

PubMed1992

Effective prevention of chemotherapy--induced phlebitis by low-dose heparin: a prospective randomised trial.

In a prospective randomised trial patients receiving multiple-day chemotherapy and heparin had significantly fewer local complications at the site of venous access than patients who had chemotherapy alone. The need to move peripheral venous catheters to other sites was decreased significantly, from 36% to 6%. Prophylaxis of phlebitis with low-dose continuous heparin is safe, simple, cheap and effective. It facilitates administration of multiple-day chemotherapy for the patients, the nurses and the physicians.

Adolescent↗

PubMed1997

Differential effectiveness of telephone prompts by medical and nonmedical staff in increasing survey response rates: a randomised trial.

We conducted a randomised trial to determine the differential effectiveness of a telephone prompt by a medical researcher compared with a nonmedical research assistant in improving response rates of general practitioners to a survey and to compare personnel costs. A national random sample of Australian general practitioners was allocated randomly to two intervention groups. In advance of a self-administered questionnaire, Group A (n = 184) received a telephone prompt by a medical researcher and Group B (n = 189) a prompt by an experienced nonmedical research assistant. Other aspects of survey administration were identical for both groups. The five-month cumulative response rate obtained by the medical researcher (81 per cent) was not significantly different from that of 72 percent obtained by the research assistant (chi 2 = 3.3, 1 df, P = 0.07). For Group A, 279 telephone calls, consuming 23 hours 15 minutes, were made. Group B required more calls (384) and more time (32 hours). Using the relevant award pay scales, the estimated personnel costs for each group were $631 and $601 respectively. We conclude that an experienced nonmedical research assistant is as effective as a medical practitioner in administering telephone prompts to enhance survey response rates, although savings are not necessarily made.

Costs and Cost Analysis↗

PubMedDate not supplied

Laser photocoagulation of soft drusen in early age-related maculopathy (ARM). The one-year results of a prospective, randomised trial.

In this prospective, randomised trial, 19 patients (mean age 72.2 +/- 6.6 years) with soft drusen maculopathy and good visual acuity (0.93 +/- 0.1) were treated with argon green laser photocoagulation. Fundus colour photography and fluorescein angiography were performed at study entry and after 3, 6 and 12 months. Nineteen patients (mean age 68.5 +/- 6.2 years) with visual acuity 0.95 +/- 0.1 and similar fundus changes served as a control group. The area occupied by drusen within a circular zone was calculated in the fundus colour photographs (radius 2500 microns) and in the angiograms (radius 1250 microns). Mean drusen area of the treatment group did not differ from that of the control group at study entry (p > 0.5-0.7). In the treatment group, mean drusen area had decreased significantly from 7.87% to 2.93% (p = 0.00013) and from 19.22% to 7.15% (p < 0.0001) at 12 months respectively in the colour photographs and in the angiograms. Visual acuity and colour contrast sensitivity did not change. No complications were seen in the treated group. In the control group, mean drusen area increased from 8.33% to 10.69% and from 17.41% to 22.05%, respectively. These differences did not reach statistical significance. When comparing the 12-month change in drusen area in the two groups, significant differences were found both in fundus colour photographs and angiograms (p < 0.001). In the control group, mean visual acuity decreased to 0.89 +/- 0.1 (p = 0.008) and mean colour contrast threshold for the tritan axis increased significantly (p = 0.044), indicating impairments of retinal function. Three patients in the control group advanced to an exudative stage of the disease.

Aged↗

PubMed2002

Single flexible sigmoidoscopy screening to prevent colorectal cancer: baseline findings of a UK multicentre randomised trial.

BACKGROUND: This randomised controlled trial is examining the hypothesis that a single flexible sigmoidoscopy screening offered at around age 60 years can lower the incidence and mortality of colorectal cancer. We report here on acceptability, safety, feasibility, and yield. METHODS: Men and women aged 55-64 years, in 14 UK centres, who responded to a mailed questionnaire that they would attend for flexible sigmoidoscopy screening if invited, were randomly assigned screening or control (ratio one to two). The control group was not contacted. Small polyps were removed during screening, and colonoscopy was undertaken if high-risk polyps (three or more adenomas, size 1 cm or greater, villous, severely dysplastic, or malignant) were found. FINDINGS: Of 354,262 people asked about their interest in having flexible sigmoidoscopy screening, 194,726 (55%) responded positively, and 170,432 eligible individuals were randomised. Attendance among those assigned screening was 71% (40,674 of 57,254). 2131 (5%) were classified as high-risk and referred for colonoscopy; 38,525 with no polyps or only low-risk polyps detected were discharged. Distal adenomas were detected in 4931 (12.1%) and distal cancer in 131 (0.3%). Proximal adenomas were detected in 386 (18.8% of those undergoing colonoscopy) and proximal cancer in nine cases (0.4%). 62% of cancers were Dukes' stage A or locally excised. There was one perforation after flexible sigmoidoscopy and four after colonoscopy. An average of 48 people were screened, and two or three colonoscopy referrals generated, per centre each week. Interpretation Our flexible sigmoidoscopy screening regimen is acceptable, feasible, and safe. The prevalence of neoplasia is high, and colonoscopy referral rates of 5% are acceptable.

Adenoma↗

PubMed1999

Randomised trials in ovarian cancer: trial design considerations.

Randomised clinical trials are considered the definitive source of evidence for guiding decisions in clinical practice. The concept of a clinical trial is based on sound scientific, ethical, and practical principles. The strength of evidence that an individual trial provides is assessed on the manner in which these principles are incorporated into the design and execution of the trial. Since the way these principles are incorporated into a trial is judgmental, the strength of evidence from an individual trial is a matter of degree. The purpose of this paper is to present some of the scientific, ethical and practical considerations surrounding the selection of endpoints and determination of sample size for trials in ovarian cancer.

Female↗

PubMed2005

Enzymatic versus autolytic debridement of chronic leg ulcers: a prospective randomised trial.

OBJECTIVE: A randomised clinical trial (n = 42) compared the effectiveness of two approaches to debriding chronic leg ulcers: TenderWet 24, which is designed to support the autolytic degradation process, and Iruxol N (Santyl), an enzymatic treatment claimed to enhance the degradation process. METHOD: Patients were randomly assigned to one of the two treatment groups for three weeks. Wounds were evaluated weekly for the amount of eschar/slough, the area of healthy granulation and the re-epithelialised area. RESULTS: During days 1-14 slough within the groups was reduced by almost 19% for TenderWet 24 and by 9% for Iruxol N, followed by an increase of 26% and 10% respectively in granulation tissue. These effects were less accentuated during days 7-21. There was a further 11% improvement in tissue debridement for the TenderWet 24 group and a relapse (+9.1%) in the Iruxol N group. CONCLUSION: Although TenderWet 24 appeared to be more efficient in a few cases, the general efficacy of the two products appeared to be almost the same as no statistically significant superiority of either product was found.

Aged↗

PubMed1991

Biodegradable pin fixation of elbow fractures in children. A randomised trial.

A prospective randomised clinical trial was undertaken to compare biodegradable polyglycolic acid pins with standard Kirschner wires used to fix displaced elbow fractures in children. Twenty-four children were enrolled in the trial; 14 had fractures of the lateral condyle of the humerus, eight of the medial epicondyle and two had olecranon fractures. Eleven fractures were fixed with Kirschner wires and 13 with polyglycolic acid pins. Fracture union with full function occurred in all cases within six months. Kirschner wires caused problems including infection in three cases, soft-tissue ossification in one and they required removal under general anaesthesia in nine cases. No such complications occurred with polyglycolic acid pins but one patient in this group developed avascular necrosis and premature fusion of the medial epicondyle.

Adolescent↗

PubMed2006

Histopathological risk factors for ipsilateral breast events after breast conserving treatment for ductal carcinoma in situ of the breast--results from the Swedish randomised trial.

AIM: The primary aims were to study risk factors for an ipsilateral breast event (IBE) after sector resection for ductal carcinoma in situ of the breast (DCIS) in a trial comparing adjuvant radiotherapy to no therapy and to assess predictive factors for response to radiotherapy. Secondary aims were to analyse reproducibility of the histopathological evaluation and to estimate correctness of diagnosis in the trial. SETTING: A randomised trial in Sweden (the SweDCIS trial), including 1046 women with a median of 5.2 years of follow-up in a population, offered routine mammographic screening. METHODS: A case-cohort design with a total of 161 cases of IBE (42 of those being members of the subcohort) and 284 sampled for the sub-cohort. Ninety five percent of the participants' slides could be retrieved and were re-evaluated by three experienced pathologists. RESULTS: Low nuclear grade (NG 1-2) and absence of necrosis halves the risk of IBE in both irradiated and non-irradiated patients. Lesion size, margins of excision and age at diagnosis did not modify these associations. The presence of necrosis modified the effect of radiotherapy: relative risk was 0.40 with necrosis present and 0.07 with necrosis absent (p-value for interaction 0.068). In all subsets of prognostic factors, radiotherapy conferred a substantial benefit. The risk factors for in situ and invasive IBE were similar. The agreement between pathologists was moderate (kappa=0.486). Correctness of diagnosis in the subcohort of SweDCIS was 84.8%. CONCLUSION: Although nuclear grade and necrosis carry prognostic information, we could not define a group with very low risk after sector resection alone. Radiotherapy has a protective effect in all substrata of risk factors studied. The interaction between the presence of necrosis and radiotherapy is a clinically and biologically relevant research area.

Breast Neoplasms↗

PubMed2000

Rhythm or rate control in atrial fibrillation--Pharmacological Intervention in Atrial Fibrillation (PIAF): a randomised trial.

BACKGROUND: Atrial fibrillation is the most commonly encountered sustained cardiac arrhythmia. Restoration and maintenance of sinus rhythm is believed by many physicians to be superior to rate control only. However, there are no prospective data that compare both therapeutic strategies. METHODS: The Pharmacological Intervention in Atrial Fibrillation (PIAF) trial was a randomised trial in 252 patients with atrial fibrillation of between 7 days and 360 days duration, which compared rate (group A, 125 patients) with rhythm control (group B, 127 patients). In group A, diltiazem was used as first-line therapy and amiodarone was used in group B. The primary study endpoint was improvement in symptoms related to atrial fibrillation. FINDINGS: Over the entire observation period of 1 year, a similar proportion of patients reported improvement in symptoms in both groups (76 responders at 12 months in group A vs 70 responders in group B, p=0.317). Amiodarone administration resulted in pharmacological restoration of sinus rhythm in 23% of patients. Walking distance in a 6 min walk test was better in group B compared with group A, but assessment of quality of life showed no differences between groups. The incidence of hospital admission was higher in group B (87 [69%] out of 127 vs 30 [24%] out of 125 in group A, p=0.001). Adverse drug effects more frequently led to a change in therapy in group B (31 [25%] patients compared with 17 [14%] in group A, p=0.036). INTERPRETATION: With respect to symptomatic improvement in patients with atrial fibrillation, the therapeutic strategies of rate versus rhythm control yielded similar clinical results overall. However, exercise tolerance is better with rhythm control, although hospital admission is more frequent. These data may serve as a basis to select therapy in individual patients.

Adult↗

PubMed2004

Quantifying trade-offs: quality of life and quality-adjusted survival in a randomised trial of chemotherapy in postmenopausal patients with lymph node-negative breast cancer.

We evaluated quality of life (QL) and quality-adjusted survival in International Breast Cancer Study Group Trial IX, a randomised trial including 1669 eligible patients receiving tamoxifen for 5 years or three prior cycles of cyclophosphamide, methotrexate and 5-fluorouracil (CMF) followed by 57 months tamoxifen. During the time with CMF toxicity (Tox), without symptoms and toxicity (TWiST), and following relapse (Rel), patients scored their QL indicators and a utility indicator for subjective health estimation between 'perfect' and 'worst' health. Scores were averaged within Tox, TWiST and Rel and transformed to utilities. Mean durations for the three transition times were weighted with utilities to obtain mean quality-adjusted TWiST (Q-TWiST). Patients receiving CMF reported significantly worse scores for most QL domains at month 3, but less hot flushes. After completing chemotherapy, there were no differences by treatment groups. Benefits evaluated by Q-TWiST favoured the additional chemotherapy. CMF provided 3 more months of Q-TWiST for patients with ER-negative tumours, but CMF provided no benefit in Q-TWiST for patients with ER-positive tumours. Q-TWiST analysis based on patient ratings is feasible in large-scale cross-cultural clinical trials.

Adult↗

PubMed2005

Efficacy and safety of cholesterol-lowering treatment: prospective meta-analysis of data from 90,056 participants in 14 randomised trials of statins.

BACKGROUND: Results of previous randomised trials have shown that interventions that lower LDL cholesterol concentrations can significantly reduce the incidence of coronary heart disease (CHD) and other major vascular events in a wide range of individuals. But each separate trial has limited power to assess particular outcomes or particular categories of participant. METHODS: A prospective meta-analysis of data from 90,056 individuals in 14 randomised trials of statins was done. Weighted estimates were obtained of effects on different clinical outcomes per 1.0 mmol/L reduction in LDL cholesterol. FINDINGS: During a mean of 5 years, there were 8186 deaths, 14,348 individuals had major vascular events, and 5103 developed cancer. Mean LDL cholesterol differences at 1 year ranged from 0.35 mmol/L to 1.77 mmol/L (mean 1.09) in these trials. There was a 12% proportional reduction in all-cause mortality per mmol/L reduction in LDL cholesterol (rate ratio [RR] 0.88, 95% CI 0.84-0.91; p<0.0001). This reflected a 19% reduction in coronary mortality (0.81, 0.76-0.85; p<0.0001), and non-significant reductions in non-coronary vascular mortality (0.93, 0.83-1.03; p=0.2) and non-vascular mortality (0.95, 0.90-1.01; p=0.1). There were corresponding reductions in myocardial infarction or coronary death (0.77, 0.74-0.80; p<0.0001), in the need for coronary revascularisation (0.76, 0.73-0.80; p<0.0001), in fatal or non-fatal stroke (0.83, 0.78-0.88; p<0.0001), and, combining these, of 21% in any such major vascular event (0.79, 0.77-0.81; p<0.0001). The proportional reduction in major vascular events differed significantly (p<0.0001) according to the absolute reduction in LDL cholesterol achieved, but not otherwise. These benefits were significant within the first year, but were greater in subsequent years. Taking all years together, the overall reduction of about one fifth per mmol/L LDL cholesterol reduction translated into 48 (95% CI 39-57) fewer participants having major vascular events per 1000 among those with pre-existing CHD at baseline, compared with 25 (19-31) per 1000 among participants with no such history. There was no evidence that statins increased the incidence of cancer overall (1.00, 0.95-1.06; p=0.9) or at any particular site. INTERPRETATION: Statin therapy can safely reduce the 5-year incidence of major coronary events, coronary revascularisation, and stroke by about one fifth per mmol/L reduction in LDL cholesterol, largely irrespective of the initial lipid profile or other presenting characteristics. The absolute benefit relates chiefly to an individual's absolute risk of such events and to the absolute reduction in LDL cholesterol achieved. These findings reinforce the need to consider prolonged statin treatment with substantial LDL cholesterol reductions in all patients at high risk of any type of major vascular event.

Cause of Death↗

PubMed1997

Randomised trials of new procedures: problems and pitfalls.

Randomised trials that compare new procedures with established ones must avoid prerandomisation bias and must allocate patients to treatment groups based on objective or quantitative criteria, not on subjective clinical judgment. Risk, length of follow up, and sample size must be used to calculate the statistical power of the study, so that a significant difference between treatments does not remain undetected (a type II error). There should already be sufficient experience with the new procedure so that complication rates have stabilised, and participating operators are equally comfortable with all procedures being studied. Even with the above stipulations, randomised trials that compare medical with procedural treatment pose additional problems (many of which have been omitted from this necessarily brief discussion); few such studies have had a major impact on clinical practice. The most useful randomised studies of procedures are those that compare one procedure with another, or those that assess a specific refinement in an established procedure, such as the use of different anticoagulation regimens for coronary stents. Fortunately, clinically useful information has always been available from non-randomised studies. The recent trend towards meta-analysis of large clinical series can substitute for those randomised studies that are unlikely to be helpful.

Drug Therapy↗

PubMed2000

Effects of a silicone-coated polyamide net dressing and calcium alginate on the healing of split skin graft donor sites: a prospective randomised trial.

An open randomised prospectively controlled trial was performed to assess the healing efficacy, slippage rate and degree of discomfort on removal of calcium alginate and a silicone-coated polyamide net dressing on split skin graft donor sites. Sixteen patients were randomised to the calcium alginate group and 14 to the silicone-coated group. The donor sites were assessed at days 7, 10, 14 and up to day 21. The mean time to healing in the calcium alginate group was 8.75 +/- 0.78 days (range 7 to 14 days) compared to 12 +/- 0.62 days (range 7 to 16 days) for the silicone-coated group (p < 0.01). Although more silicone-coated dressings slipped (5 versus 1), the difference was not statistically significant. Pain during the first dressing change was assessed using a visual analogue pain scale. Although no significant differences were found between the groups, it was necessary to change the dressing protocol in the silicone-coated arm of the trial after entering the first two patients. Overlaid absorbent gauze adhered to the donor site through the fenestrations in the dressing necessitating the placement of paraffin gauze between the experimental dressing and the overlying cotton gauze. There was one infection in the study, occurring in the alginate group. Based on these results we recommend calcium alginate as the dressing of choice for split skin graft donor sites.

Adult↗