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PubMed2001

Randomised trials within the general practice evaluation program. Why so few?

BACKGROUND: The General Practice Evaluation Program (GPEP) provided competitive funding for general practice research from 1990-1999. METHODS: Projects funded by GPEP between November 1990 and December 1999 were audited to determine the extent of randomised trials and other interventional studies. RESULTS: Thirty-three (13%) of the 248 projects were interventional studies; of these 21 (8% of all projects) were randomised trials. CONCLUSIONS: While GPEP has made a significant contribution toward Australian general practice research, few randomised trials and other interventional studies have been funded. Reasons include the specific evaluative focus and restrictions on project duration and funding. Randomised trials should be supported within future general practice research funding.

Australia↗
PubMed2000

Are beta-blockers effective in patients who develop heart failure soon after myocardial infarction? A meta-regression analysis of randomised trials.

BACKGROUND: The great majority of post-infarction studies of beta-blockers were conducted in an era when these agents were widely held to be contra-indicated for the management of heart failure. We now know that beta-blockers are highly effective for the management of patients with chronic stable heart failure. However, there remains uncertainty about their role in the setting of post-infarction heart failure and ventricular dysfunction. AIM: the primary objective in this paper, was to investigate the extent to which heart failure or evidence of major cardiac dysfunction influenced outcome in previous trials of beta-blockers in heart failure after myocardial infarction. METHODS: We assessed the extent to which the inclusion of patients with heart failure or major cardiac dysfunction influenced outcome in randomised trials of long-term use of beta-blockade after myocardial infarction. The primary analysis was to assess the extent to which the proportion of patients included in each trial with heart failure influenced the relative odds of all-cause mortality in the trials. All randomised trials without crossover with treatment lasting more than one month and with 50 or more patients were considered. All those that provided information on the proportion of patients with heart failure or major cardiac dysfunction in the original or subsequent articles were included in the analysis. RESULTS: Overall treatment with a beta-blocker was associated with a 22.6% reduction in the odds of death (95% C1 11-32.3%). There were very few data on the effects of beta-blockers after myocardial infarction in patients with documented left ventricular systolic dysfunction. In the analysis that included heart failure as a factor, treatment with a beta-blocker was associated with a non-significant interaction with the presence of heart failure. However, because the group including heart failure patients were at higher risk, the absolute benefit of treatment with beta-blockers appeared greater in this group. CONCLUSIONS: This analysis suggests that the relative benefit of beta-blockers on mortality after a myocardial infarction is similar in the presence or absence of heart failure but that the absolute benefit may be greater in the former. However, as current clinical practice has changed radically from the time when the majority of these trials were conducted, further trial evidence would be desirable.

Adrenergic beta-Antagonists↗
PubMed2003

Including a 'no active intervention' arm in surgical trials is possible: evidence from the CLasP randomised trial.

OBJECTIVES: To examine the impact of including a 'no active intervention' arm (called 'conservative management') in a randomised controlled trial comparing treatments (including surgery) for men with lower urinary tract symptoms related to benign prostatic enlargement. METHODS: Outcomes 7.5 months after randomisation were acceptability of randomisation, overall acceptability of and satisfaction with conservative management, impact on quality of life, perceived need for further treatment and treatment failure (defined a priori). RESULTS: In total, 177 (out of 755) patients refused randomisation, including 31% who did not want surgery and 22% who wanted surgery. Most men randomised to conservative management were willing to undertake it as part of a trial but at the end of the trial they were divided between those who wanted to continue with it and those who expected surgery. At follow-up, 39% of conservative management patients requested surgery, and interference of symptoms with life and an unsuccessful outcome were more commonly reported in this arm. There were no appreciable differences between treatment groups in terms of treatment failures. CONCLUSIONS: Including a 'no active intervention' arm did not appear to have a detrimental effect on patient recruitment or the completion of this trial in the short-term; overall, conservative management was successfully completed by the majority of patients during the trial period, suggesting that researchers need not avoid including a no-intervention arm in surgical trials as long as they take care with its presentation.

Aged↗
PubMed2002

Evidence from randomised trials on the long-term effects of hormone replacement therapy.

CONTEXT: Over the past few decades hormone replacement therapy (HRT) has been used increasingly by post-menopausal women in western countries. The need for objective data on long-term effects prompted the setting up of randomised trials to compare cancer and cardiovascular disease endpoints in HRT users and non-users. With the early termination of part of the Women's Health Initiative trial (JAMA 2002; 288: 321-33), it is timely to review the evidence from such studies. STARTING POINT: Four randomised trials including over 20000 women followed up for 4.9 years, on average, have now reported on the effect of HRT for major, potentially fatal, conditions. Overall, HRT users had a significantly increased incidence of breast cancer, stroke, and pulmonary embolism; a significantly reduced incidence of colorectal cancer and fractured neck of femur; but no significant change in endometrial cancer or coronary heart disease.There was no significant variation across the trials in the results for any condition. Three trials had recruited women with previous cardiovascular disease and the fourth, the Women's Health Initiative, had recruited healthy women. Combined oestrogen/progestagen HRT was used in three trials and oestrogen alone in one. Use of HRT over a 5-year period by healthy postmenopausal women in western countries is estimated to cause an extra breast cancer,stroke, or pulmonary embolus in about 6 per 1000 users aged 50-59 and 12 per 1000 aged 60-69. Over the same period, the estimated reduction in incidence of colorectal cancer or fractured neck of femur is 1.7 per 1000 users aged 50-59 and 5.5 per 1000 aged 60-69. The increased incidence of any one of these conditions is greater than any reduction, the estimated net excess over 5 years being 1 per 230 users aged 50-59, and 1 per 150 aged 60-69. WHERE NEXT: Substantial new data should soon be available from randomised trials of oestrogen-alone HRT versus placebo, whereas few additional trial data on combined HRT are expected for about a decade. Existing randomised trials are too small to describe reliably the effect of HRT on important but rarer conditions, such as ovarian cancer, or on cause-specific mortality. Nor will they provide information about other types of oestrogen or progestagen. Answers to such questions will require judicious analysis and interpretation of data from observational studies.

Aged↗
PubMed2002

Generation of allocation sequences in randomised trials: chance, not choice.

The randomised controlled trial sets the gold standard of clinical research. However, randomisation persists as perhaps the least-understood aspect of a trial. Moreover, anything short of proper randomisation courts selection and confounding biases. Researchers should spurn all systematic, non-random methods of allocation. Trial participants should be assigned to comparison groups based on a random process. Simple (unrestricted) randomisation, analogous to repeated fair coin-tossing, is the most basic of sequence generation approaches. Furthermore, no other approach, irrespective of its complexity and sophistication, surpasses simple randomisation for prevention of bias. Investigators should, therefore, use this method more often than they do, and readers should expect and accept disparities in group sizes. Several other complicated restricted randomisation procedures limit the likelihood of undesirable sample size imbalances in the intervention groups. The most frequently used restricted sequence generation procedure is blocked randomisation. If this method is used, investigators should randomly vary the block sizes and use larger block sizes, particularly in an unblinded trial. Other restricted procedures, such as urn randomisation, combine beneficial attributes of simple and restricted randomisation by preserving most of the unpredictability while achieving some balance. The effectiveness of stratified randomisation depends on use of a restricted randomisation approach to balance the allocation sequences for each stratum. Generation of a proper randomisation sequence takes little time and effort but affords big rewards in scientific accuracy and credibility. Investigators should devote appropriate resources to the generation of properly randomised trials and reporting their methods clearly.

Epidemiology↗
PubMed1994

Collaborative overview of randomised trials of antiplatelet therapy--II: Maintenance of vascular graft or arterial patency by antiplatelet therapy. Antiplatelet Trialists' Collaboration.

OBJECTIVE: To determine the efficacy of antiplatelet therapy in maintaining vascular patency in various categories of patients. DESIGN: Overviews of 46 randomised trials of antiplatelet therapy versus control and 14 randomised trials comparing one antiplatelet regimen with another. SETTING: Randomised trials that could have been available by March 1990 and in which vascular graft or arterial patency was to be studied systematically. SUBJECTS: About 8000 patients at varying degrees of risk of vascular occlusion (by virtue of disease or of having some vascular procedure) were in trials of antiplatelet therapy versus control and 4000 such patients were in trials directly comparing different antiplatelet regimens. RESULTS: Overall, antiplatelet therapy produced a highly significant (2P < 0.0001) reduction in vascular occlusion, with similar proportional reductions in several different types of patients. Hence the absolute reductions tended to be largest among patients at highest risk of occlusion, with smaller but still significant absolute reductions among lower risk patients. The proportions of patients with confirmed occlusion among those allocated antiplatelet therapy versus appropriately adjusted control proportions (and mean scheduled treatment durations and net absolute benefits) were: (a) among about 4000 patients with coronary artery grafts, 21% antiplatelet therapy v 30% control (seven month benefit about 90 patients protected per 1000 allocated antiplatelet therapy (2P < 0.00001)); (b) among about 800 patients after coronary angioplasty, 4% antiplatelet therapy v 8% control (six month benefit about 40/1000 (2P = 0.02)); (c) among about 3000 patients with peripheral artery procedures or disease, 16% antiplatelet therapy v 25% control (19 month benefit about 90/1000 (2P < 0.00001)); (d) among about 400 renal patients with a shunt or fistula placed for haemodialysis access, 17% antiplatelet therapy v 39% control (two month benefit about 200/1000 (2P < 0.00001)). Indirect comparisons between the effects of starting treatment before these vascular procedures and starting soon after them indicated similar sized benefits. As well as preventing subclinical occlusion, antiplatelet therapy produced a significant (2P = 0.002) reduction of about one quarter in the odds of suffering a "vascular event" (non-fatal myocardial infarction, non-fatal stroke, or vascular death). Various antiplatelet regimens (chiefly aspirin alone or aspirin plus dipyridamole) were studied but there was no significant evidence of differences between their effects on arterial occlusion or vascular events. Data on bleeding were incomplete but no large excess with antiplatelet therapy was apparent. CONCLUSION: Antiplatelet therapy (chiefly aspirin alone or aspirin plus dipyridamole) greatly reduces the risk of vascular occlusion in a wide range of patients at high risk of this complication. Further studies are required to determine exactly when treatment should start (to limit any perioperative bleeding while still preventing most early occlusion) and for how long it should be continued.

Arterial Occlusive Diseases↗
PubMed2005

Ventilation strategies and outcome in randomised trials of high frequency ventilation.

OBJECTIVE: Randomised controlled trials comparing elective use of high frequency ventilation (HFV) with conventional mechanical ventilation (CMV) in preterm infants have yielded conflicting results. We hypothesised that the variability of results may be explained by differences in study design, ventilation strategies, delay in initiation of HFV, and use of permissive hypercapnia. METHODS: Randomised controlled trials comparing the elective use of HFV with any form of CMV were identified. Trials were classified according to the ventilation strategies used for HFV and CMV and oscillator device employed. For cumulative meta-analyses, trials were arranged by the following covariables: mean duration until randomisation, Paco(2) limits, publication date, and sample size. Odds ratios (OR) and 95% confidence intervals were calculated using fixed and random effects models. RESULTS: Seventeen randomised trials enrolling 3776 patients were included. Unlike previous meta-analyses, there was no significant difference in the incidence of bronchopulmonary dysplasia or death (OR 0.87, 0.75-1.00) and severe intraventricular haemorrhage grade 3-4 (1.14, 0.96-1.37). The incidence of air leaks (OR 1.23, 1.06-1.44) was significantly increased with HFV. Subgroup analyses and cumulative meta-analyses demonstrated that trial results were related to the ventilation strategies used for HFV and CMV. No influence was found for mean time to randomisation, degree of permissive hypercapnia, or sample size. CONCLUSIONS: Heterogeneity among trials of elective HFV compared to CMV in preterm infants is mainly due to differences in ventilatory strategies. Optimising CMV strategy appeared to be as effective as using HFV in improving pulmonary outcome in preterm infants.

High-Frequency Ventilation↗
PubMed2004

A meta-analysis of randomised trials suggests a survival benefit for combined radiotherapy and radical cystectomy compared with radical radiotherapy for invasive bladder cancer: are these data relevant to modern practice?

OBJECTIVE: Treatment options for muscle-invasive bladder cancer include radical cystectomy or radical radiotherapy, and the prevailing choice varies by country. The ideal treatment would be a bladder-preserving therapy without compromising survival. The objective of this review was to compare the overall survival after radical surgery (cystectomy) with radical radiotherapy in patients with muscle-invasive cancer. MATERIALS AND METHODS: We searched the Cochrane Controlled Trials Register, Medline, EMBASE, Cancerlit, Healthstar and the Database of Abstracts of Reviews of Effectiveness. Authors of unpublished data were contacted. Randomised trials comparing surgery (alone or with preoperative radiotherapy) with radiotherapy were eligible for assessment. Three reviewers assessed trial quality based on the Cochrane Guidelines. Data were extracted from the text of the article or extrapolated from the Kaplan-Meier plot. The Peto odds ratio was determined to compare the overall survival and disease-specific survival. Analysis was performed on an intention-to-treat basis and treatment actually received. RESULTS: No randomised trials comparing surgery alone with radiotherapy alone were identified. Three randomised trials comparing preoperative radiotherapy followed by radical cystectomy (surgery) versus radical radiotherapy with salvage cystectomy (radical radiotherapy) were eligible for assessment. These trials represented a total of 439 patients, 221 randomised to surgery and 218 to radical radiotherapy. Three trials were combined for the overall survival results, and one was evaluable for the disease-specific survival analysis. The mean overall survival (intention-to-treat analysis) at 3 and 5 years were 45% and 36% for surgery, and 28% and 20% for radiotherapy, respectively. Peto odds ratio (95% confidence interval [CI]) analysis consistently favoured surgery in terms of overall survival. The results were significantly in favour of surgery at 3 years (OR = 1.91, 95% CI 1.30-2.82) and at 5 years (OR = 1.85, 95% CI 1.22 -2.82). On a treatment-received basis, the results were significantly in favour of surgery at 3 years (OR 1.84, 95% CI 1.17-2.90) and 5 years (OR 2.17, 95% CI 1.39-3.38) for overall survival, and at 3 years (OR 1.96, 95% CI 1.06-3.65) for disease-specific survival. CONCLUSIONS: The analysis of this review suggests that there is an overall survival benefit with combined preoperative radiotherapy plus radical surgery compared with radical radiotherapy plus salvage cystectomy in patients with muscle-invasive bladder cancer. However, it must be considered that only three trials were included for analysis, the patient numbers were small and that many patients did not receive the treatment they were randomised to. It must also be noted that many improvements in radiotherapy and surgery have taken place since the initiation of these trials; therefore, the data may not be readily extrapolated to modern practice. Ideally, a new trial comparing modern bladder-sparing therapy with the latest surgical approach to this disease is required.

Cystectomy↗
PubMed1993

The prevalence of myocardial ischemia six months after thrombolytic treatment of acute coronary episodes. A subset of a placebo controlled, randomised trial, the ASSET Study.

The purpose of this prospectively conducted study was to determine the prevalence of transient myocardial ischemia, evaluated from 24 h continuous ECG monitoring and exercise test, 6 months after inclusion in the Anglo Scandinavian Study of Early Thrombolysis (the ASSET trial, a randomised, placebo controlled study of alteplase for survival in patients with suspected acute myocardial infarction (AMI)), and to relate these findings to development of cardiac events. Of the 58 consecutively studied patients ischemic responses were found in 13 (45%) of 29 patients initially treated with placebo, and in 21 (72%) of 29 alteplase treated patients (P = 0.03). After another 6 months, i.e. 12 months after the acute event, two patients were dead, two had non-fatal reinfarctions and three had coronary artery by-pass surgery in the group with ischemic response; no events were recorded in patients without ischemia (P < 0.05). Alteplase treated patients more often had late myocardial ischemia, and cardiac events were found in patients with ischemia. Since the ASSET trial has demonstrated significantly higher short- and long-term survival rate in the alteplase treated group, it was indicated (1) that alteplase treated patients were better positioned for sustaining subsequent ischemia and thus cardiac events due to preservation of viable myocardial tissue, and (2) that late ischemia in the setting of initial alteplase treatment may convey other information than ischemia occurring in placebo treated patients.

Adrenergic beta-Antagonists↗
PubMed1998

Tamoxifen for early breast cancer: an overview of the randomised trials. Early Breast Cancer Trialists' Collaborative Group.

BACKGROUND: There have been many randomised trials of adjuvant tamoxifen among women with early breast cancer, and an updated overview of their results is presented. METHODS: In 1995, information was sought on each woman in any randomised trial that began before 1990 of adjuvant tamoxifen versus no tamoxifen before recurrence. Information was obtained and analysed centrally on each of 37000 women in 55 such trials, comprising about 87% of the worldwide evidence. Compared with the previous such overview, this approximately doubles the amount of evidence from trials of about 5 years of tamoxifen and, taking all trials together, on events occurring more than 5 years after randomisation. FINDINGS: Nearly 8000 of the women had a low, or zero, level of the oestrogen-receptor protein (ER) measured in their primary tumour. Among them, the overall effects of tamoxifen appeared to be small, and subsequent analyses of recurrence and total mortality are restricted to the remaining women (18000 with ER-positive tumours, plus nearly 12000 more with untested tumours, of which an estimated 8000 would have been ER-positive). For trials of 1 year, 2 years, and about 5 years of adjuvant tamoxifen, the proportional recurrence reductions produced among these 30000 women during about 10 years of follow-up were 21% (SD 3), 29% (SD 2), and 47% (SD 3), respectively, with a highly significant trend towards greater effect with longer treatment (chi2(1)=52.0, 2p<0.00001). The corresponding proportional mortality reductions were 12% (SD 3), 17% (SD 3), and 26% (SD 4), respectively, and again the test for trend was significant (chi2(1) = 8.8, 2p=0.003). The absolute improvement in recurrence was greater during the first 5 years, whereas the improvement in survival grew steadily larger throughout the first 10 years. The proportional mortality reductions were similar for women with node-positive and node-negative disease, but the absolute mortality reductions were greater in node-positive women. In the trials of about 5 years of adjuvant tamoxifen the absolute improvements in 10-year survival were 10.9% (SD 2.5) for node-positive (61.4% vs 50.5% survival, 2p<0.00001) and 5.6% (SD 1.3) for node-negative (78.9% vs 73.3% survival, 2p<0.00001). These benefits appeared to be largely irrespective of age, menopausal status, daily tamoxifen dose (which was generally 20 mg), and of whether chemotherapy had been given to both groups. In terms of other outcomes among all women studied (ie, including those with "ER-poor" tumours), the proportional reductions in contralateral breast cancer were 13% (SD 13), 26% (SD 9), and 47% (SD 9) in the trials of 1, 2, or about 5 years of adjuvant tamoxifen. The incidence of endometrial cancer was approximately doubled in trials of 1 or 2 years of tamoxifen and approximately quadrupled in trials of 5 years of tamoxifen (although the number of cases was small and these ratios were not significantly different from each other). The absolute decrease in contralateral breast cancer was about twice as large as the absolute increase in the incidence of endometrial cancer. Tamoxifen had no apparent effect on the incidence of colorectal cancer or, after exclusion of deaths from breast or endometrial cancer, on any of the other main categories of cause of death (total nearly 2000 such deaths; overall relative risk 0.99 [SD 0.05]). INTERPRETATION: For women with tumours that have been reliably shown to be ER-negative, adjuvant tamoxifen remains a matter for research. However, some years of adjuvant tamoxifen treatment substantially improves the 10-year survival of women with ER-positive tumours and of women whose tumours are of unknown ER status, with the proportional reductions in breast cancer recurrence and in mortality appearing to be largely unaffected by other patient characteristics or treatments.

Adult↗
PubMed2006

A phase 2b randomised trial of the candidate malaria vaccines FP9 ME-TRAP and MVA ME-TRAP among children in Kenya.

OBJECTIVE: The objective was to measure the efficacy of the vaccination regimen FFM ME-TRAP in preventing episodes of clinical malaria among children in a malaria endemic area. FFM ME-TRAP is sequential immunisation with two attenuated poxvirus vectors (FP9 and modified vaccinia virus Ankara), which both deliver the pre-erythrocytic malaria antigen construct multiple epitope-thrombospondin-related adhesion protein (ME-TRAP). DESIGN: The trial was randomised and double-blinded. SETTING: The setting was a rural, malaria-endemic area of coastal Kenya. PARTICIPANTS: We vaccinated 405 healthy 1- to 6-year-old children. INTERVENTIONS: Participants were randomised to vaccination with either FFM ME-TRAP or control (rabies vaccine). OUTCOME MEASURES: Following antimalarial drug treatment children were seen weekly and whenever they were unwell during nine months of monitoring. The axillary temperature was measured, and blood films taken when febrile. The primary analysis was time to a parasitaemia of over 2,500 parasites/mul. RESULTS: The regime was moderately immunogenic, but the magnitude of T cell responses was lower than in previous studies. In intention to treat (ITT) analysis, time to first episode was shorter in the FFM ME-TRAP group. The cumulative incidence of febrile malaria was 52/190 (27%) for FFM ME-TRAP and 40/197 (20%) among controls (hazard ratio = 1.52). This was not statistically significant (95% confidence interval [CI] 1.0-2.3; p = 0.14 by log-rank). A group of 346 children were vaccinated according to protocol (ATP). Among these children, the hazard ratio was 1.3 (95% CI 0.8-2.1; p = 0.55 by log-rank). When multiple malaria episodes were included in the analyses, the incidence rate ratios were 1.6 (95% CI 1.1-2.3); p = 0.017 for ITT, and 1.4 (95% CI 0.9-2.1); p = 0.16 for ATP. Haemoglobin and parasitaemia in cross-sectional surveys at 3 and 9 mo did not differ by treatment group. Among children vaccinated with FFM ME-TRAP, there was no correlation between immunogenicity and malaria incidence. CONCLUSIONS: No protection was induced against febrile malaria by this vaccine regimen. Future field studies will require vaccinations with stronger immunogenicity in children living in malarious areas.

Journal Article↗
PubMed2006

Second- and third-generation aromatase inhibitors as first-line endocrine therapy in postmenopausal metastatic breast cancer patients: a pooled analysis of the randomised trials.

The purpose of this study was to estimate in all randomised trials the relative risk of overall response rate (ORR), clinical benefit (CB), time to progression (TTP), overall survival (OS), and toxicity of aromatase inhibitors (AI), compared with tamoxifen (Tam) as first-line endocrine therapy in postmenopausal metastatic breast cancer (PMBC) women. Prospective randomised studies were searched through computerised queries of MEDLINE, EMBASE, and the American Society of Clinical Oncology (ASCO) abstract database. Relative risk, 95% confidence interval, and heterogeneity were derived according to the inverse variance and Mantel-Haenszel method and Q statistics. Six phase III prospective randomised trials including 2787 women were gathered. A significant advantage in ORR (P = 0.042), TTP (P = 0.007), and CB (P = 0.001) in favour of AI over Tam was detected at the fixed effects model. These results were not significant at the random effects model, owing to the significant heterogeneity. On the contrary, no difference was registered for OS (P = 0.743) with no significant heterogeneity. Regarding toxicity, Tam caused more frequently thromboembolic events (P = 0.005) and vaginal bleeding (P = 0.001) compared with AI. Aromatase inhibitors appear to be superior to Tam as first-line endocrine option in PMBC women. Owing to a component of variability between the six studies analysed, the random effects estimates differed from corresponding fixed ones. Investigators should assess heterogeneity of trial results before deriving summary estimates of treatment effect.

Aromatase Inhibitors↗
PubMed2002

Annotation: randomised trials.

BACKGROUND: This annotation describes the uses of randomised controlled trials (RCTs) in clinical child psychology and psychiatry. METHOD: It explores the scientific basis for randomised designs, the conceptual and methodological issues that can arise when using them, alternative methods, and future directions. RESULTS: There are many issues that have to be tackled when using randomised trials to answer questions about the effectiveness of interventions used by child mental health professionals. The most important are conceptual issues concerning the design of these studies, practical issues, and issues about the interpretation of the results. There are some situations in which randomised trials are not possible or ideal and alternative strategies may therefore be needed. Future RCTs should be more explicit about whether their primary purpose is to further scientific knowledge or to evaluate the benefit of a treatment in routine clinical practice. Future trials should also have outcomes of unequivocal significance and be reported in accordance with standardised guidelines. CONCLUSIONS: Well-designed and unambiguously reported RCTs usually provide the best possible evidence about the effectiveness of an intervention. RCTs are not, however, the only way of establishing cause and effect and their results should always be interpreted in the light of other evidence.

Humans↗
PubMed1993

Antithrombotic therapy in acute ischaemic stroke: an overview of the completed randomised trials.

A formal statistical overview of all truly randomised trials was undertaken to determine whether antithrombotic therapy is effective and safe in the early treatment of patients with acute stroke. There were 15 completed randomised controlled trials of the value of early antithrombotic treatment in patients with acute stroke. The regimes tested in acute presumed or confirmed ischaemic stroke were: heparin, 10 trials with 1047 patients: oral anticoagulants, one trial with 51 patients: antiplatelet therapy, three trials with 103 patients. Heparin was tested in one trial with 46 patients with acute haemorrhagic stroke. Outcome measures were deep venous thrombosis (confirmed by I125 scanning or venography), pulmonary embolism, death from all causes, haemorrhagic transformation of cerebral infarction, level of disability in survivors. In patients with acute ischaemic stroke, allocation to heparin was associated with a highly significant 81% (SD 8, 2p < 0.00001) reduction in deep venous thrombosis detected by I125 fibrinogen scanning or venogram. Only three trials systematically identified pulmonary emboli, which occurred in 6/106 (5.7%) allocated control vs 3/132 (2.3%) allocated heparin, a non-significant 58% reduction (SD 45.7, 2p > 0.1). There were relatively few deaths in the trials in patients with presumed ischaemic stroke: 94/485 (19.4%) among patients allocated to the control group vs 79/497 (15.9%) among patients who were allocated heparin. The observed 18% (SD 16) reduction in the odds of death was not statistically significant. The least biased estimated of the effect of treatment on haemorrhagic transformation of the cerebral infarct (HTI) comes from trials where all patients were scanned at the end of treatment, irrespective of clinical deterioration; using this analysis, haemorrhagic transformation occurred in 7/102 (6.9%) control vs 8/106 (7.5%) treated, a non-significant 12% increase (SD 56, 2p > 0.1). These data cannot exclude the possibility that heparin substantially increases the risks of HTI. No data on disability in survivors could be obtained. Early heparin treatment might be associated with substantial reductions in deep venous thrombosis (and probably also pulmonary embolism) and possibly a one fifth reduction in mortality (equivalent to the avoidance of 20-40 early deaths per thousand patients treated.) However, the data were wholly inadequate on safety, particularly on the risk of haemorrhagic transformation of the infarct and on the hazards of heparin therapy in patients with known intracerebral haemorrhage. The trials of oral anticoagulants (15 deaths among 57 patients) and antiplatelet therapy (two deaths among 103 patients) were too small to be informative. Much larger randomized trials-comparing aspirin, heparin and the combination of both drugs against control-in patients with acute ischaemic stroke are justified (and several are now planned or underway).

Acute Disease↗
PubMed2006

Does rectal cancer shrinkage induced by preoperative radio(chemo)therapy increase the likelihood of anterior resection? A systematic review of randomised trials.

BACKGROUND AND PURPOSE: According to common conviction rectal tumour shrinkage after preoperative radio(chemo)therapy increases the likelihood of anterior resection (AR). In order to verify this belief, we performed a systematic review of randomised trials. PATIENTS AND METHODS: We identified 10 randomised trials encompassing altogether 4596 patients in whom preoperative radio(chemo)therapy resulted in tumour shrinkage in the experimental arm as compared to the control arm. RESULTS: Tumour shrinkage observed in the experimental groups did not result in a statistically significant higher ARs rate in any study when we performed an analysis of all the randomised cases. Subgroups of patients considered to be candidates for abdominoperineal resection before randomisation were identified in three trials. A statistically significantly higher rate of ARs was demonstrated in the experimental arm of the CAO/ARO/AIO 94 study. However, in that study, sphincter preservation was a secondary endpoint and some features of the trial may bias the estimation of the effect. The benefit of sphincter preservation was not confirmed by subgroup analyses performed in the Lyon R90-01 study and in the Polish study, which were originally designed to evaluate the sphincter preservation issue. CONCLUSION: The body of evidence gathered from randomised trials does not support the concept of a beneficial effect of preoperative radiotherapy on the ARs rate.

Clinical Trials as Topic↗
PubMed1998

Polychemotherapy for early breast cancer: an overview of the randomised trials. Early Breast Cancer Trialists' Collaborative Group.

BACKGROUND: There have been many randomised trials of adjuvant prolonged polychemotherapy among women with early breast cancer, and an updated overview of their results is presented. METHODS: In 1995, information was sought on each woman in any randomised trial that began before 1990 and involved treatment groups that differed only with respect to the chemotherapy regimens that were being compared. Analyses involved about 18,000 women in 47 trials of prolonged polychemotherapy versus no chemotherapy, about 6000 in 11 trials of longer versus shorter polychemotherapy, and about 6000 in 11 trials of anthracycline-containing regimens versus CMF (cyclophosphamide, methotrexate, and fluorouracil). FINDINGS: For recurrence, polychemotherapy produced substantial and highly significant proportional reductions both among women aged under 50 at randomisation (35% [SD 4] reduction; 2p<0.00001) and among those aged 50-69 (20% [SD 3] reduction; 2p<0.00001); few women aged 70 or over had been studied. For mortality, the reductions were also significant both among women aged under 50 (27% [SD 5] reduction; 2p<0.00001) and among those aged 50-69 (11% [SD 3] reduction; 2p=0.0001). The recurrence reductions emerged chiefly during the first 5 years of follow-up, whereas the difference in survival grew throughout the first 10 years. After standardisation for age and time since randomisation, the proportional reductions in risk were similar for women with node-negative and node-positive disease. Applying the proportional mortality reduction observed in all women aged under 50 at randomisation would typically change a 10-year survival of 71% for those with node-negative disease to 78% (an absolute benefit of 7%), and of 42% for those with node-positive disease to 53% (an absolute benefit of 11%). The smaller proportional mortality reduction observed in all women aged 50-69 at randomisation would translate into smaller absolute benefits, changing a 10-year survival of 67% for those with node-negative disease to 69% (an absolute gain of 2%) and of 46% for those with node-positive disease to 49% (an absolute gain of 3%). The age-specific benefits of polychemotherapy appeared to be largely irrespective of menopausal status at presentation, oestrogen receptor status of the primary tumour, and of whether adjuvant tamoxifen had been given. In terms of other outcomes, there was a reduction of about one-fifth (2p=0.05) in contralateral breast cancer, which has already been included in the analyses of recurrence, and no apparent adverse effect on deaths from causes other than breast cancer (death rate ratio 0.89 [SD 0.09]). The directly randomised comparisons of longer versus shorter durations of polychemotherapy did not indicate any survival advantage with the use of more than about 3-6 months of polychemotherapy. By contrast, directly randomised comparisons did suggest that, compared with CMF alone, the anthracycline-containing regimens studied produced somewhat greater effects on recurrence (2p=0.006) and mortality (69% vs 72% 5-year survival; log-rank 2p=0.02). But this comparison is one of many that could have been selected for emphasis, the 99% CI reaches zero, and the results of several of the relevant trials are not yet available. INTERPRETATION: Some months of adjuvant polychemotherapy (eg, with CMF or an anthracycline-containing regimen) typically produces an absolute improvement of about 7-11% in 10-year survival for women aged under 50 at presentation with early breast cancer, and of about 2-3% for those aged 50-69 (unless their prognosis is likely to be extremely good even without such treatment). Treatment decisions involve consideration not only of improvements in cancer recurrence and survival but also of adverse side-effects of treatment, and this report makes no recommendations as to who should or should not be treated.

Adult↗
PubMed2005

Identifying outcome reporting bias in randomised trials on PubMed: review of publications and survey of authors.

OBJECTIVE: To examine the extent and nature of outcome reporting bias in a broad cohort of published randomised trials. DESIGN: Retrospective review of publications and follow up survey of authors. Cohort All journal articles of randomised trials indexed in PubMed whose primary publication appeared in December 2000. MAIN OUTCOME MEASURES: Prevalence of incompletely reported outcomes per trial; reasons for not reporting outcomes; association between completeness of reporting and statistical significance. RESULTS: 519 trials with 553 publications and 10,557 outcomes were identified. Survey responders (response rate 69%) provided information on unreported outcomes but were often unreliable--for 32% of those who denied the existence of such outcomes there was evidence to the contrary in their publications. On average, over 20% of the outcomes measured in a parallel group trial were incompletely reported. Within a trial, such outcomes had a higher odds of being statistically non-significant compared with fully reported outcomes (odds ratio 2.0 (95% confidence interval 1.6 to 2.7) for efficacy outcomes; 1.9 (1.1 to 3.5) for harm outcomes). The most commonly reported reasons for omitting efficacy outcomes included space constraints, lack of clinical importance, and lack of statistical significance. CONCLUSIONS: Incomplete reporting of outcomes within published articles of randomised trials is common and is associated with statistical non-significance. The medical literature therefore represents a selective and biased subset of study outcomes, and trial protocols should be made publicly available.

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