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PubMed2001

[The use of state of the art statistical methodology in biomedical research: the example of methodology for interim analyses in clinical trials].

BACKGROUND: Clinical research stresses the need for evidence as a basis for setting research agendas. The extent to which current clinical research involves recent advances in biostatistics is not well known. AIM: This manuscript focuses on the use of interim analyses accumulating data in clinical trials. MATERIAL AND METHODS: A PubMed search was conducted for the period 1990-2000. Keywords used included 'interim analysis', 'alpha-spending function', and 'early termination', after subsetting to 'randomised controlled trials (RCT)' that were 'multicenter' since these particular studies are more likely to have external monitoring boards conducting interim analyses. Studies were grouped by clinical discipline and also by journals of high or low impact index. RESULTS: Thirteen thousand two hundred eighty two articles with both 'RCT' and 'multicenter' were found. Of these, the 'interim analysis' keyword yielded 879 articles, of which only 163 (19%) studies reported their methodology. The percentages varied by clinical discipline and by journal type. A 25% random sample of the articles were further reviewed to investigate the appropriateness of the interim analysis methods used. DISCUSSION: Recent articles in the medical literature attempt to make the interim analysis methods more accessible to clinicians. However, further training of statisticians involved in clinical trials is needed as well.

Clinical Trials as Topic↗
PubMed1998

Cardiac rehabilitation in the elderly.

Rehabilitation for patients with heart disease consists of exercise training, behavioral interventions, counseling, and education with the goal of improving physiologic and psychosocial status. The Cardiac Rehabilitation Clinical Practice Guidelines, recently published in the United States, list the most substantial benefits of cardiac rehabilitation as an improvement in exercise tolerance, symptoms, blood lipid levels, and psychosocial well-being, and a reduction in cigarette smoking, stress, and mortality. With the evidence-base on the elderly in the Guidelines derived from 1 non-randomized controlled trial and 7 observational studies, the efficacy and effectiveness of cardiac rehabilitation is based almost exclusively on data generated on young and middle-aged males. We have located an additional 10 randomized and 2 non-randomized controlled trials published since the Guidelines, but only one provided age-specific data. The elderly are the fastest growing segment of the population, and may be more responsive to the effects of cardiac rehabilitation as they often have greater initial disability and less independence than younger patients. While referral of elderly persons to cardiac rehabilitation services appears safe and warranted in the secondary prevention of heart disease, the lack of rigorous scientific evidence has created an important clinical research and clinical policy vacuum which urgently needs to be filled.

Adult↗
PubMed2005

[Biometrical methods for the proof of efficacy in regulatory submissions. Non-inferiority in clinical studies].

The increasing number of approved efficacious therapies for various indications raises the question of whether the inclusion of a placebo group is still justified. In addition, pharmaceutical companies and regulatory agencies acknowledge that it may be sufficient to prove that a new therapy is comparable to an approved reference therapy regarding efficacy and safety in some situations. This becomes especially striking for the approval to market a generic drug. Another, perhaps even more important example is the increasing resistance of bacteria which calls for new antibiotics based on new therapeutic principles without having the claim for better efficacy. In these situations, a comparable efficacy would constitute progress. In the present paper, we discuss the numerous methodological challenges and approaches to overcome these problems that occur when it is not possible or even not wanted to use the classic approach of a randomized placebo-controlled superiority trial. Here, the field of medical biometry, which has proved in the last 25 years to be an integral part of the development of new drugs, demonstrates its suitability as a flexible and scientifically based means to fulfil the requirements resulting from clinical practice. Starting from the fact that statistical methods are not able to prove "equality" of two treatments, "shifted" hypotheses are considered and their importance for the different study designs is discussed. We show how the classic hypotheses known from placebo-controlled clinical trials can be embedded in this concept. The implications of this approach for the analysis and interpretation of study results is further discussed. The relevant guidelines of the European and US regulatory agencies are taken into account.

Biometry↗
PubMed2002

The quality of research in sports journals.

OBJECTIVE: To examine the evidence base of sports medicine research. METHODS: A sample of four major journals that present core research in sport and exercise medicine (British Journal of Sports Medicine, Medicine and Science in Sports and Exercise, Journal of Sports Medicine and Physical Fitness, and Physical Therapy) was examined using assessment criteria taken from the READER method. RESULTS: Randomised controlled trials comprised 10% or less of all original research articles. Observational/descriptive studies were the most commonly published study design. There was a highly significant difference (p<0.0001) in the contents of the four journals but when they were compared by categorising the better quality methods together (randomised control trial, case-control, and cohort studies), the difference was not significant (p = 0.09). CONCLUSIONS: The overall pattern of publication type seems remarkably stable over medical journals, indicating that the quality of sports medicine research is comparable to that in other specialities.

Clinical Trials as Topic↗
PubMed2001

Tolerability of 3-day, once-daily azithromycin suspension versus standard treatments for community-acquired paediatric infectious diseases.

Tolerability of azithromycin oral suspension, 10 mg/kg once daily for 3 days, was assessed in paediatric patients (< or = 18 years) with respiratory or skin and soft-tissue infections. Of 2425 patients evaluated, 1213 received azithromycin and 1212 received standard regimens of amoxycillin/clavulanic acid, cefaclor, cefixime, ceftriaxone, clarithromycin, erythromycin, or penicillin V. The incidence of treatment-related adverse events was significantly lower in patients receiving azithromycin than comparators (7.9 vs. 11.5%, P=0.003), while discontinuation rates were similar (1.0 and 1.1%, respectively). Significantly fewer gastrointestinal events were recorded for azithromycin than comparators (6.5 vs. 9.9%, P=0.002), and their duration was significantly shorter (mean 2.3 vs. 5.0 days, P=0.0001). Azithromycin paediatric oral suspension is well tolerated and associated with significantly fewer adverse events than comparators.

Adolescent↗
PubMed2000

[Guidelines for diagnosis and treatment of acute urinary tract problems in women].

BACKGROUND: Available guidelines for the management of symptoms of lower urinary tract infections (UTI) in women give conflicting recommendations. MATERIAL AND METHODS: We searched The Cochrane Library, Medline and other sources for evidence that met explicit inclusion criteria for the relevant options and outcomes identified. The validity of included studies was assessed. Draft recommendations were widely circulated and discussed in focus groups with patients and physician assistants. RESULTS: The probability that a woman with dysuria or frequency has bacteriuria, is 80%. The probability of UTI given a negative result of a dipstick test is 50%. Evidence suggests that antibiotics will rapidly relieve symptoms, but there are limited data from placebo-controlled randomised trials. Population based studies show that many women do not visit physicians for symptoms of UTI. Women with symptoms of UTI can be treated with antibiotics without examination of the urine. Women with earlier episodes of UTI can be offered treatment by telephone. Antibiotics for three days is sufficient based on eradication of bacteriuria. Women should be seen by a physician if the symptoms are atypical. INTERPRETATION: Implementing these guidelines could result in better service to women with UTIs. More evidence about the effects of antibiotics and other treatments is needed.

Anti-Bacterial Agents↗
PubMed2003

Risks and benefits of rate control versus maintenance of sinus rhythm.

There are 2 fundamental approaches to managing patients with recurrent atrial fibrillation (AF): to restore and maintain sinus rhythm with cardioversion and/or antiarrhythmic drugs, or to control the ventricular rate only. Over the past few years, there have been several important prospective clinical trials comparing rate control with rhythm control in patients with recurrent AF. The Pharmacological Intervention in Atrial Fibrillation (PIAF) trial was the first prospective randomized study to test the hypothesis of equivalency between the 2 management strategies for AF. The trial demonstrated that rate control was not inferior to rhythm control with respect to symptoms, quality of life, or number of hospitalizations in patients with persistent AF. The Strategies of Treatment in Atrial Fibrillation (STAF) trial was a pilot study that enrolled approximately 200 patients with AF who were randomized to either ventricular rate control or cardioversion and maintenance of sinus rhythm. The results showed that over a 1-year period there was little difference in outcome in terms of morbidity or symptoms. In the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) trial, patients with AF and risk factors for stroke were randomized to either rhythm control or rate control, with both groups receiving anticoagulation with warfarin. There was no difference in the composite end point of death, disabling stroke or anoxic encephalopathy, major bleeding, or cardiac arrest between the 2 arms. In addition, no major differences were noted in functional status or quality of life. The Rate Control Versus Electrical Cardioversion (RACE) trial also reached a similar conclusion. Thus, rate control is an acceptable primary strategy for management of patients with recurrent AF.

Amiodarone↗
PubMed1995

Calcium channel blockers for heart rate control in atrial fibrillation complicated by congestive heart failure.

OBJECTIVES: To review the safety and efficacy of verapamil and diltiazem with respect to ventricular response in atrial fibrillation (AF) in the setting of left ventricular (LV) systolic dysfunction. DATA SOURCES: Pertinent articles were identified through a MEDLINE search of the English language literature from 1984 to 1993, followed by a manual search of the bibliographies of pertinent articles. STUDY SELECTION: Studies selected were case reports, controlled trials, review articles and editorials. DATA EXTRACTION: Effects of verapamil and diltiazem on hemodynamics, ventricular response in AF, clinical parameters and mortality were reviewed. DATA SYNTHESIS: There are limited data about the effects of verapamil and diltiazem on ventricular function in patients with congestive heart failure. In vitro diltiazem has fewer negative inotropic effects than verapamil. Clinically there are some reports of hemodynamic and clinical deterioration in patients with significant LV dysfunction given verapamil although most patients improve with verapamil. There are more data concerning diltiazem in the setting of AF complicated by congestive heart failure. The drug does not appear to exacerbate heart failure, although hypotension can result. In chronic AF complicated by heart failure, there is concern that diltiazem may increase mortality. Options for therapy are digoxin, beta-blockers and atrioventricular node ablation. CONCLUSIONS: Calcium channel blockers may have a role in the acute reduction of ventricular response in patients with AF complicated by congestive heart failure; however, their safety in chronic heart rate control remains to be proven.

Atrial Fibrillation↗
PubMed2004

Safety and efficacy of the combination of trastuzumab with docetaxel for HER2-positive women with advanced breast cancer. A review of the existing clinical trials and results of the expanded access programme in the UK.

Trastuzumab is a humanised monoclonal antibody against the extracellular domain of HER2 (human epidermal growth factor receptor-2) that is overexpressed in about 25% of human breast cancers. It has shown clinical benefit in HER2-positive breast cancer cases when used alone or in combination with chemotherapy. Trastuzumab increases the response rate to chemotherapy and prolongs survival when used in combination with taxanes. In this article, we review the clinical trials where trastuzumab has been administered together with docetaxel, and we present the results of the trastuzumab expanded access programme (EAP) in the UK. Combination of trastuzumab with docetaxel results in similar response rates and time-to-progression with the trastuzumab/paclitaxel combinations. The toxicity of the combination and the risk of heart failure are low. The clinical data for the docetaxel/trastuzumab combination indicate a favourable profile from both the efficacy and the safety point of view and confirm the feasibility and safety of trastuzumab administration both as monotherapy and in combination with docetaxel.

Antibodies, Monoclonal↗
PubMed2004

TMC-114 (Tibotec).

Tibotec (formerly Tibotec-Virco) is developing TMC-114 as a potential treatment for HIV-1 infection. In February 2001, TMC-126 was revealed as the series prototype, from which TMC-114 was developed. Because of its improved antiviral and superior pharmacokinetic properties, TMC-114 was selected for clinical development. Phase II trials of TMC-114 are underway.

Anti-HIV Agents↗
PubMed1999

[Evaluation of preventive studies of Chinese Journal of Tuberculosis and Respiratory Diseases 1978-1997].

OBJECTIVE: To investigate the current situation of clinical trial about preventive research paper on respiratory diseases in China. To stress the design of the research, and to improve the quality of the studies. METHODS: All the preventive and treatment studies of Chinese Journal of Tuberculosis and Respiratory Diseases (1978-1997) were assessed according to evidence based medicine (EBM) standard. RESULTS: In the past 20 years, 394 preventive study papers were published, 41 were random control trial (RCT), 50 were clinical control trial (CCT), the total percentage of RCT and CCT was 23.1%, and quality problem also existed. CONCLUSIONS: The design of the study in the respiratory diseases is not rigorous, thus the accuracy of the result is greatly affected. Improving the design of the research and the statistics method is very important to improve the quality of the research.

China↗
PubMedDate not supplied

Verapamil revisited: a transition in novel drug delivery systems and outcomes.

Verapamil, the oldest calcium-channel blocker, is now being rediscovered and reevaluated in the light of new novel drug delivery systems and new evidence-based trials. Verapamil, a phenylalkylamine, is useful in the treatment of hypertension, stable angina, and narrow QRS supraventricular arrhythmias. This calcium antagonist is effective in both young and old, and both black and white hypertensive patients, and is free of metabolic side effects. Verapamil has a well-documented history as an effective antianginal agent when directly compared with a beta-blocker, and is more effective in reducing myocardial ischemia compared with amlodipine monotherapy. Because of the short half-life of verapamil, drug delivery systems are used to prolong the duration of action. Novel drug delivery systems using encapsulated beads or a modified osmotic pump have been designed to be taken at nighttime to provide maximal blood pressure reduction in the early morning hours and effective 24-hour blood pressure control, and to avoid excessive blood pressure reduction during sleep. The Verapamil in Hypertension and Atherosclerosis Study has documented equivalent effectiveness of verapamil compared with chlorthalidone, but showed superior plaque regression and reduced events in subjects with the greatest plaques with verapamil treatment. The Angina Prognosis Study in Stockholm, comparing verapamil and metoprolol for stable angina, found no difference in total cardiovascular mortality or combined cardiovascular events. Other large ongoing randomized, multicenter trials, including Controlled-Onset Verapamil Investigation of Cardiovascular Endpoints and the International Verapamil-Trandolapril Study, will expand our knowledge of the role of verapamil in the treatment of hypertension.

Angina, Unstable↗
PubMed1995

Changes in study design, gender issues, and other characteristics of clinical research published in three major medical journals from 1971 to 1991.

OBJECTIVE: To examine trends in study design and other characteristics of original research published in JAMA, Lancet, and the New England Journal of Medicine (NEJM) between 1971 and 1991. DESIGN: A retrospective cross-sectional study of original clinical research published in JAMA, Lancet, and NEJM during 1971, 1981, and 1991. MEASUREMENTS: Four hundred forty-four articles were independently reviewed by at least two investigators and classified according to study design and other preselected study characteristics. Changes over time were analyzed by chi-square tests for categorical variables and analysis of variance for continuous variables. MAIN RESULTS: Clinical results doubled, from 17% of all articles in 1971 to 35% in 1991 (p < 0.004), while case series decreased from 30% to 4% (p < 0.0001). Of 118 clinical trials, randomized controlled trials increased from 31% to 76% (p < 0.003) and nonrandomized controlled trials decreased from 42% to 8% (p < 0.002). Multicenter studies increased from 10% to 39% (p < 0.0001) and the prevalence of health services research increased from none in 1971 to 12% in 1991 (p < 0.001). The proportion of the studies explicitly excluding women from the subject population decreased from 11% in 1971 to 3% in 1991 (p < 0.03). In 1991 7% of the studies were composed entirely of men subjects, while only 0.7% of the studies were specific to men's health. Twelve percent of the studies in 1991 were specific to women's health. Between 1971 and 1991 there was no change in the prevalence of women first authors or studies addressing women's or minorities' health issues. CONCLUSIONS: Several important changes in clinical research studies published in JAMA, Lancet, and NEJM have taken place between 1971 and 1991. Clinical trials have increased in frequency, largely replacing studies containing ten or fewer subjects. Health services research has increased in prevalence, reflecting growing interest in studies addressing the delivery of health care. Our data support the hypothesis that exclusion of women from clinical research studies is an important contributor to the paucity of data concerning women's health.

Clinical Trials as Topic↗