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At least 127 records · Page 7Linked to original sources
PubMed1999

Systematic reviews of strategies to prevent motor vehicle injuries.

BACKGROUND: Information on which strategies have been shown to be effective, which are ineffective, and which strategies have been inadequately evaluated is important for both public policy and future research. OBJECTIVE: To provide systematic reviews of the literature on important strategies to prevent motor vehicle injuries. METHODS: The Injury Control Research Centers (ICRCs) funded by the Centers for Disease Control and Prevention identified 9 important motor vehicle injury prevention strategies. A systematic review of the literature in 9 different computerized databases was conducted to identify relevant controlled trials. These were critically reviewed and summarized. RESULTS: A total of 54,078 citations were reviewed; 1,111 met initial screening criteria. The reports for these citations were obtained and critically reviewed by the ICRCs. Standard criteria for inclusion of articles in the review and for evaluating the methodological quality of the articles were applied. Few randomized controlled trials were found; most controlled studies were either comparisons over time and/or across different populations. Nevertheless, these studies were able to be summarized to provide meaningful conclusions about the effectiveness of various interventions to decrease morbidity and mortality from motor vehicle crashes. CONCLUSIONS: A large body of literature on motor vehicle injury interventions exists. The summary of this literature will provide useful information to direct policy and future research efforts.

Accidents, Traffic↗
PubMed2001

In search of truth: the role of systematic reviews and meta-analyses for assessing the effectiveness of rehabilitation with oral implants.

BACKGROUND: It is difficult to determine the effectiveness or potential harm of dental therapies. Thus, any tools able to condense reliable scientific information would be of benefit. PURPOSE: To discuss methods for the assessment of the scientific literature and, in particular, of systematic reviews for evaluating the effectiveness of oral implant rehabilitation procedures. MATERIALS AND METHODS: Various study designs and methods to identify scientific evidence are described, discussed, and ranked. Issues on how to critically appraise randomized controlled clinical trials (RCTs) and systematic reviews are presented. RESULTS: Properly conducted RCTs and structured critical systematic reviews are the gold standard of clinical research for assessing whether a therapeutic intervention is effective. In the field of oral implantology, there is an urgent need to implement more RCTs and to summarize their results in systematic reviews. CONCLUSIONS: Searching of the truth requires training and critical skill. Dentists should be trained on how to integrate their clinical experience with evidence-based research and on how to discriminate between clinically useful scientific information and less useful research.

Animals↗
PubMed1998

Proposed consensus for definitions and endpoints for clinical trials of acute kidney transplant rejection.

Progress in transplantation therapeutics requires validation from multicenter trials in which enrollment criteria and endpoint definitions have been standardized. A database of acute rejection was established from 19 North American, European, and Australian transplant centers and included parameters on rejection diagnosis and treatment of 50 consecutive rejection episodes from each center. Patient demographics, induction and maintenance immunosuppressive therapies, antirejection agents (drug, dose, duration), clinical signs (decrease in urine volume, presence of fever of > or =38.5 degrees C), serum creatinine concentration (nadir, at rejection, daily during antirejection therapy to 15 days, and days 30, 90, 180, and 365 after rejection date), rejection biopsy findings, morbidity, recurrence of rejection, and renal function at 1 year were recorded for 953 rejection episodes. From these data, three definitions were proposed. Acute rejection was defined as an immunologic process resulting in a serum creatinine increase of > or =0.4 mg/dL, with or without clinical signs, and should include a biopsy confirmation that has been standardized to the Banff criteria. Corticosteroid-resistant rejection was defined as a rejection episode in which a minimum of 250 to 1000 mg of methylprednisolone administered as initial therapy fails to result in stabilization or reduction of the serum creatinine after 3 days of corticosteroid treatment. Successful response to therapy was defined as a serum creatinine level < or =110% of the serum creatinine on the day of the rejection diagnosis and a return of the serum creatinine to or below the rejection creatinine level by 5 days of therapy with maintenance of this response for a minimum of 30 days. The work represented in the Efficacy Endpoints Database provides a step toward improving definitions in clinical trials. Continuity in clinical trial design should lead to improvements in evaluation of outcomes and, thereby have an effect on clinical practice.

Acute Disease↗
PubMed1998

Clinical safety evaluation of combination vaccines.

The development plan for new combination vaccines should include clinical studies designed to provide an adequate safety database (as well as efficacy data) to support licensure. Ideally, randomized studies to compare the safety of the combination vaccine with the separately administered components (or already licensed combinations of components) should be performed. For new combination vaccines having components with proven efficacy, comparative immunogenicity data may provide a sufficient basis to support efficacy, precluding the need for a large efficacy study. In the absence of the safety database that would have been derived from such an efficacy study, it is important to conduct a comparative safety study with a sample size suitable for the evaluation of less common adverse events. For large safety trials, a simplified design where only a subset of subjects is assessed in detail for the more common adverse events may be appropriate.

Biometry↗
PubMed2000

Consensus conferences must include a systematic search and categorization of the evidence.

BACKGROUND: Ideally, a consensus panel combines expert knowledge with external evidence derived from the literature. To date, many consensus conferences do not use a structured approach to search the literature, but simply compile an add-on reference list from all papers cited by the panelists. This study examined how well such panelists retrieved the relevant literature. METHODS: We used the reference lists of nine surgeons who took part in a consensus conference on common bile duct stones. We included all papers that were referred to as randomized controlled trials (RCTs). We then compared this list with a database search in order to calculate sensitivity and specificity. RESULTS: The nine experts cited between 35 and 518 papers, but only eight papers on average were RCTs. Of the 49 papers that the experts believed to be RCTs, only 23 actually were RCTs. The sensitivity resp. specificity for correctly identifying an RCT was 0.21 (95% Cl, 0.11-0.30) resp. 0.80 (95% Cl; 0.64-0.95). RCTs that included the word "randomized" in their title were significantly more likely to be identified (relative risk, 1.31; 95% Cl, 1.18-1.45). CONCLUSION: Our data indicate that consensus panelists usually do not perform systematic literature searches, but simply use their favorite papers to back up their arguments. Because this may lead to a biased selection of the evidence base on which the consensus statements are founded, a systematic search of all relevant articles should become a mandatory task in any consensus or guideline process.

Consensus Statements as Topic↗
PubMed2000

Stabilization of disease as an indicator of clinical benefit associated with chemotherapy in non-small cell lung cancer patients.

In Phase II oncology studies, response rate has traditionally been used to assess activity. However stabilization of disease (SD) may also provide patient benefit. To assess the value of SD (stabilization of measurable disease for at least 8 weeks) as a predictor of survival following chemotherapy in patients with non-small cell lung cancer (NSCLC), we have analyzed data from 198 NSCLC patients receiving topotecan i.v. or orally as first-line therapy either as single agent or in combination. Proportional hazards (Cox) regression models showed that responders [complete response (CR) + partial response (PR), 1.5% and 11.6% respectively] had an estimated risk of death that was 9.8% (95% CI: 4.2% to 22.7%) of that for progressive disease (PD) (60.1% of the patient population). Similarly, patients with SD (26.8% of the patient population) showed a potential benefit with a risk of death that was 27.7% of the one of patients with PD (95% CI: 17.8% to 43.1%). In conclusion SD may be a useful indicator of patient benefit from chemotherapy for NSCLC.

Administration, Oral↗
PubMed1998

Quality assessment of reports on clinical trials in the Journal of Hepatology.

BACKGROUND/AIMS: Electronic searches on databases for randomised clinical trials and controlled clinical trials do not identify as many trials as handsearches, and trial reporting may be flawed. The aims were to identify all fully reported randomised clinical trials in the Journal of Hepatology and to make a qualitative assessment of the reporting. METHODS: The publications were identified by systematically handsearching the full text of the journal and searching MEDLINE. Central dimensions of trial quality were used to assess the reporting quality of the trials. RESULTS: Randomised clinical trials represented 8.4% of the original articles (171/2028). Ten original articles (0.5%) could not be classified. A search on MEDLINE identified 81.3% of the randomised clinical trials, i.e., 139 out of the 171 identified by the handsearch. A total of 166 randomised clinical trials could be quality assessed. Forty-seven (28.3%) of them reported adequate generation of allocation sequence; 22 (13.3%) adequate allocation concealment; 95 (57.2%) allowed intention-to-treat analysis with only a few losses to follow-up; 50 (30.1%) were double-blind; 33 (19.9%) reported sample-size calculations; 13 trials (7.8%) employed the crossover design; and the median number of subjects per intervention arm in parallel group trials was 19 subjects (interquartile range: 11-31; range: 5-519). The quality of reporting was significantly better in regular issue articles than in supplement articles. CONCLUSIONS: Many important randomised clinical trials are published in the Journal of Hepatology, but there seems to be ample room for improvement of quality of reporting.

Controlled Clinical Trials as Topic↗
PubMed1996

A methodology for evidence-based health policymaking: the Welsh Protocol Enhancement Project.

The emergence of evidence-based health care at an operational level is well underway in the National Health Service, driven on by clinical effectiveness initiatives. Unless evidence-based care is supported by evidence-based policymaking, the environment will not be conducive to effective professional practice. The article describes a methodology that has been developed to meet the needs of the Project for the Enhancement of the Welsh-Protocols for Investment in Health Gain. A detailed description of the background, aims, methods, planning, and supporting documentation of the project is given. The methodological principles are transferable to other policymaking scenarios.

Clinical Protocols↗
PubMed1994

Comparison of chemotherapy and bone marrow transplants using two independent clinical databases.

Comparing the outcome of chemotherapy and bone marrow transplants in the absence of a randomized trial is difficult but necessary for diseases where small numbers of patients make such trials difficult if not impossible. To address this issue for adults with acute lymphoblastic leukemia in first remission, we created an empirical database using two separate datasets, one from the International Bone Marrow Transplant Registry and the other from two multicenter chemotherapy studies. Prior to combining the datasets, a study protocol was developed to define inclusion criteria, outcomes to be compared and statistical methods. The main problems of a non-randomized comparison are biases potentially introduced by differences in baseline composition of the two cohorts and differences in time-to-treatment. The source of the latter bias is different distributions of waiting times between achieving complete remission and receiving post-remission therapy. Several techniques to control these biases were evaluated; each gave qualitatively similar results. These methods can easily be applied to other clinical situations where randomized trials are not available.

Adolescent↗
PubMed2001

The use of evidence in pharmacovigilance. Case reports as the reference source for drug withdrawals.

OBJECTIVE: Withdrawal of a drug from the market for safety reasons is a serious and sometimes complex decision. The scientific evidence supporting drug withdrawals in the past years is critically appraised. METHODS: With data provided by the Spanish Medicines Agency, all drugs withdrawn from the Spanish market for safety reasons from January 1990 to December 1999 were identified. The adverse drug reactions (ADRs) were classified by the year of withdrawal, by the organ/system affected and by the alleged type of reaction (Rawlins and Thompson classification). A systematic review of the literature was performed. RESULTS: A total of 22 drugs were withdrawn from the market due to safety reasons. In 18 of 22 cases (82%), the evidence supporting the drug withdrawal came from individual case reports, cases series or the combination of data provided by randomised clinical trials and case reports. Hepatic (eight cases) and cardiac (five cases) reactions accounted for 59% (13 of 22) of the total withdrawals. In 10 of 22 (45%) cases, drug withdrawal was clearly due to type-B reactions. Only four withdrawals were based on evidence from observational studies including a comparison group. CONCLUSION: Case reports are the main source of information used to withdraw a drug from the market for safety reasons. It is necessary to improve the quality of evidence supporting the withdrawal process of drugs linked to unexpected and severe ADRs. The use of large databases to perform cohort or nested case-control analyses is the most efficient and reliable method to study type-A class effect ADRs. The implementation of such databases in different countries could increase the quality of the information on ADRs by allowing researchers to conduct efficiently these type of studies.

Adverse Drug Reaction Reporting Systems↗
PubMed1999

Twenty years of phase III trials for patients with extensive-stage small-cell lung cancer: perceptible progress.

PURPOSE: All cooperative group studies performed in North America for patients with extensive-stage small-cell lung cancer (SCLC) were evaluated to determine the pattern of the clinical trials and the outcome of patients over the past 20 years. PATIENTS AND METHODS: Phase III trials for patients with extensive-stage SCLC were identified through a search of the National Cancer Institute Cancer Therapy Evaluation Program database from 1972 to 1993. Patients with extensive-stage SCLC treated during a similar time interval listed in the Surveillance, Epidemiology, and End Results (SEER) database were also examined. Trends were tested in the number of trials over time, the number and sex of patients entered onto the trials, and the survival time of patients treated over time. RESULTS: Twenty-one phase III trials for patients with extensive-stage SCLC were initiated between 1972 and 1990. The median of the median survival times of patients treated on the control arms of the phase III trials initiated between 1972 and 1981 was 7.0 months; for those patients enrolled onto control arms between 1982 and 1990, the median survival time was 8.9 months (P =.001). Analysis of the SEER database of patients with extensive-stage SCLC over the same time period shows a similar 2-month prolongation in median survival time. CONCLUSION: Analysis of 21 phase III trials initiated in North America and the SEER database from 1972 to 1994 demonstrates that there has been a modest improvement in the survival time of patients with extensive-stage SCLC.

Carcinoma, Small Cell↗
PubMed1994

Breast cancer outcome and predictors of outcome: are there age differentials?

Several questions were addressed regarding breast cancer outcome, predictors of outcome, and young age at diagnosis. Is there evidence that outcome is worse in younger women compared with other age groups? Do younger patients have a greater frequency of adverse prognostic factors? If younger age is associated with a poor outcome, is it an intrinsic independent adverse predictor, or is the outcome worse due to poor prognostic factor profiles? Several methods were used to answer these questions and applied to those reports in which age categories were carefully defined: 1) detailed review of population-based breast cancer outcome literature, 2) synthesis of published cooperative group and single institution univariate and multivariate analyses, and 3) a new analysis of the 8738-patient San Antonio database. Overall, epidemiologic studies suggested that younger women have the worst survival outcome, when matched with similarly staged older cohorts. Univariate trends analyses confirmed that younger women more often had more positive lymph nodes, larger tumors, and negative steroid hormone receptors. Significantly more cancers in women less than 35 years of age had high S-phase fractions and abnormal expression of p53. Multivariate modeling confirmed that young age was an independent adverse predictor when a few standard factors were considered in the model, but other descriptors such as tumor grade or high S-phase fraction were more important when available. These data support the conclusion that "young age" serves as a surrogate for a greater frequency of adverse prognostic factor profiles and suggest important questions for future study.

Adult↗
PubMed2001

Use of internet technologies for data acquisition in large clinical trials.

Data acquisition for automated processing is a central aspect of clinical trials with large numbers of cases because of their extensive demand for manpower. Scientific data can be collected using data forms, which are created in Hypertext Markup Language and published on the Internet. The completed data form can be returned via E-mail or Common Gateway Interface-Script and forwarded into a study database. For the Internet-based data acquisition of a prospective multicenter trial (e.g., on endophthalmitis incidence after cataract extraction), we developed two special HTML forms that can be opened in the ophthalmology department's homepage. A large number of acquired anonymous data has been collected via Internet and automatically transferred into the trial database. The Internet provides a fast and easy avenue for the acquisition of scientific data. This method of data acquisition and data processing will become more common place in multicenter clinical trials.

Clinical Trials as Topic↗
PubMed1988

Report from the panel on the Case for Registers of Clinical Trials at the Eighth Annual Meeting of the Society for Clinical Trials.

A plenary session at the Eighth Annual Meeting of the Society for Clinical Trials addressed "The Case for Registers of Clinical Trials." There are a number of reasons for having registers of clinical trials: to promote collaboration and communication among investigators regarding new and ongoing clinical trials, to provide a basis for methodologic research, and to facilitate meta-analysis by the availability of a system of trial identification that is independent of the published literature. The experience gleaned by those involved with two existing trial registers, the International Committee on Thrombosis and Haemostasis Registry and the Oxford Database of Perinatal Trials, can be used to provide insight into the issues generic to trial registration. The time perspective to be used, inclusion and exclusion criteria, the practicability of comprehensive prospective registration, and funding are central considerations for these and other registers.

Clinical Trials as Topic↗
PubMed1990

Coordinating data management for multiple ongoing clinical trials and registries.

The Epidemiology Data Center at the University of Pittsburgh has developed a standard set of data management procedures, reports, and computing configurations for use on multicenter research projects. Based on budget restrictions and study design considerations, a project-specific data management system can be quickly constructed by utilizing appropriate components from the EDC tool kit: the PoP software system for the computerization of the database from paper forms to data entry screens; program shells for telecommunication and backup procedures; and procedural documents for providing the necessary training materials for centralized or decentralized processing environments. The EDC data flow specification provides quality control assurances from entry through statistical analysis.

Clinical Trials as Topic↗