Controlled clinical trials
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The Digitalis Investigation Group (DIG) trial was the first large simple trial conducted by the National Heart, Lung, and Blood Institute in conjunction with the Department of Veterans Affairs. A large simple trial is a major undertaking. Simplification at the sites requires careful planning and discipline. Lessons learned from the DIG trial were: (1) keep a large simple trial very simple and keep all study procedures very simple; (2) ancillary studies are important and can complement a large simple trial but require careful advanced planning; (3) anticipate special needs when shipping study drugs internationally; (4) regional coordinating centers can be very useful; (5) recruit as many capable sites as possible; (6) provide research-inexperienced sites/investigators with extra help to obtain federalwide assurance statements from the Office for Human Research Protections and institutional review board approvals; (7) adequately reimburse sites for the work completed; (8) maintain investigator enthusiasm; (9) monitor the slow performers and sites with numerous personnel changes; (10) choose an endpoint that is easy to ascertain; (11) keep the trial simple for participants; and (12) plan early for closeout and for activities between the end of the trial and publication of results.
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Control Clin Trials · Oct 2003
Promoting good clinical practices in the conduct of clinical trials: experiences in the Department of Veterans Affairs Cooperative Studies Program.
The ever-increasing concern for the welfare of volunteers participating in clinical trials and for the integrity of the data derived from those trials has generated the concept of Good Clinical Practice (GCP). The Veterans Affairs Cooperative Studies Program, in anticipation of the need to comply with GCP guidelines, developed a Site Monitoring and Review Team (SMART), which consists of a Good Clinical Practice Monitoring Group and a Good Clinical Practice Review Group. The review group conducted 335 site reviews from fiscal years (FY) 1999 through 2001 to assess and encourage adherence to GCP. ⋯ Median assessment scores for the 14 selected critical GCP items improved from 0.78 to 0.89 (p<0.001). Median scores for five of the eight GCP focus areas improved significantly (p<0.001) between the two time periods. These data suggest that the site-oriented activities of SMART combined with centralized quality assurance activities of the coordinating centers represent an integrated, versatile program to promote and assure GCP adherence and data integrity in Cooperative Studies Program trials.
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Control Clin Trials · Oct 2003
Randomized Controlled Trial Clinical TrialLook AHEAD (Action for Health in Diabetes): design and methods for a clinical trial of weight loss for the prevention of cardiovascular disease in type 2 diabetes.
Overweight and obesity are major contributors to both type 2 diabetes and cardiovascular disease (CVD). Moreover, individuals with type 2 diabetes who are overweight or obese are at particularly high risk for CVD morbidity and mortality. Although short-term weight loss has been shown to ameliorate obesity-related metabolic abnormalities and CVD risk factors, the long-term consequences of intentional weight loss in overweight or obese individuals with type 2 diabetes have not been adequately examined. ⋯ The primary study outcome is time to incidence of a major CVD event. The study is designed to provide a 0.90 probability of detecting an 18% difference in major CVD event rates between the two groups. Other outcomes include components of CVD risk, cost and cost-effectiveness, diabetes control and complications, hospitalizations, intervention processes, and quality of life.
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Control Clin Trials · Oct 2003
ReviewA group sequential, response-adaptive design for randomized clinical trials.
There has been considerable methodological research on response-adaptive designs for clinical trials but they have seldom been used in practice. The many reasons for this are summarized in an article by Rosenberger and Lachin, but the two main reasons generally cited are logistical difficulties and the potential for bias due to selection effects, "drift" in patient characteristics or risk factors over time, and other sources. Jennison and Turnbull consider a group sequential, response-adaptive design for continuous outcome variables that partially addresses these concerns while at the same time allowing for early stopping. ⋯ Limitations, such as the impact of delays in observing outcomes, are discussed, as well as areas for further research. We conclude that responsive adaptive designs may be useful for some purposes, particularly in the presence of large treatment effects, although allowing early stopping minimizes the benefits. If such a design is undertaken, the randomization and analysis should be stratified in order to avoid bias due to time trends.
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Control Clin Trials · Aug 2003
Randomized Controlled Trial Clinical TrialThe Arthritis, Diet and Activity Promotion Trial (ADAPT): design, rationale, and baseline results.
Osteoarthritis (OA) of the knee leads to restrictions of physical activity and ability to perform activities of daily living. Obesity is a risk factor for knee OA and it appears to exacerbate knee pain and disability. The Arthritis, Diet, and Activity Promotion Trial (ADAPT) was developed to test the efficacy of lifestyle behavioral changes on physical function, pain, and disability in obese, sedentary older adults with knee OA. ⋯ Other measurements included timed stair climb, distance walked in 6 minutes, strength, gait, knee pain, health-related quality of life, knee radiographs, body weight, dietary intake, and cost-effectiveness of the interventions. We report baseline data stratified by level of overweight and obesity focusing on self-reported physical function and physical performance tasks. The results from ADAPT will provide approaches clinicians should recommend for behavioral therapies that effectively reduce the incidence of disability associated with knee OA.