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Questions & Answers

What is the National Institutes of Health (NIH) Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT)?

GAIT is the first multicenter clinical trial in the United States to test the effects of the dietary supplements glucosamine and chondroitin for treatment of knee osteoarthritis. The study will test whether glucosamine and chondroitin used separately or in combination are effective in reducing pain and improving functional ability in patients with knee osteoarthritis. GAIT includes an additional study (or sub-study) that will assess whether glucosamine and chondroitin can reduce or halt the progression of knee osteoarthritis.

The University of Utah School of Medicine was awarded a contract to coordinate this study, which will be conducted at thirteen research centers across the U.S. The National Center for Complementary and Alternative Medicine (NCCAM) and the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) are two components of the National Institutes of Health (NIH) that are responsible for initiating this study.

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What is the purpose of the study?

Results of previous studies in the medical literature have yielded conflicting results on the effectiveness of glucosamine and chondroitin as treatments for osteoarthritis. This study will test the short-term (6 months) effectiveness of glucosamine and chondroitin in reducing pain and improving function in a large number of patients with knee osteoarthritis.

The study will also evaluate the impact of glucosamine and chondrotin on progression of knee osteoarthritis following an additional 18 month treatment regimen.

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What prompted the NIH to study glucosamine and chondroitin for osteoarthritis?

On January 27, 1998, the NCCAM held a meeting to discuss the need, rationale, and feasibility of conducting a Phase III study (a human study involving over 1,000 patients to test the efficacy, safety, and side effects of a substance(s) of glucosamine and chondroitin for the treatment of knee osteoarthritis. Meeting participants included experts in osteoarthritis, alternative medicine, biostatistics and family practice, and staff of the NIH and the U.S. Food and Drug Administration. The group determined that there is a real and urgent public health need to test these agents in a rigorous way, and that current scientific data support short-term testing of glucosamine and chondroitin for pain control and functional improvement of osteoarthritis.

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What is the basic design of the study?

In this study, patients will be randomly assigned to receive either (1) glucosamine alone, (2) chondroitin alone, (3) glucosamine and chondroitin in combination, (4) celecoxib (brand name Celebrex®), or (5) a placebo (an inactive substance that looks like the study substance). Glucosamine and chondroitin and their combination will be compared to a placebo to verify that these substances significantly improve joint pain and flexibility. Celecoxib, which is an established effective conventional treatment for osteoarthritis, will also be compared to placebo to validate the study design. To reduce the chance of biased results, double-blind research procedures will be used to ensure that neither the researchers nor the patients will know to which of the five treatment groups the patients belong.

In the main or primary study, each patient will be treated for 24 weeks. During this time, patients will be evaluated at 4, 8, 16, and 24 week intervals and closely monitored for improvement of their symptoms as well as for any possible adverse reactions to the agents. Medical evaluations and x rays will be used to document each patient's diagnosis. The primary outcome will be measured as improvement in pain. Improvement in function will be included as a secondary outcome. All patients will have the option to use acetaminophen (e.g., Tylenol®) as required to control severe pain from osteoarthritis throughout the clinical trial.

In the sub-study, which will evaluate the progression of knee osteoarthritis, about one-half of the patients enrolled in GAIT will receive blinded treatment for an additional eighteen months. As in the primary study, patients will not know to which treatment group they are assigned. Researchers will compare x-rays taken at the beginning of the study and after one and two years of treatment. Then they will compare and evaluate x rays from all sub-study participants to identify changes in the knee joints as a result of treatment.

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How many patients are needed and when will the study begin?

A total of 1588 people will be recruited for the study. Recruitment is currently open.

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Who will be eligible to participate in the study?

Patients with knee pain and x-ray evidence of osteoarthritis are encouraged to consider participation in the study. People who are interested in the study must not have used glucosamine for 3 months and chondroitin for 6 months prior to entering the study.

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Where will the study be conducted and how can I sign up?

The University of Utah School of Medicine, Salt Lake City, UT, will serve as the coordinating study center and oversee the research and patient recruitment efforts of the thirteen study centers. People interested in the study can contact the coordinators at any of the thirteen centers listed below.

University of Alabama at Birmingham, Birmingham AL (Larry W. Moreland, M.D.) 
Elizabeth Coffey (205) 934-9851

Cedars-Sinai Medical Center, Los Angeles, CA (Michael Weisman, M.D.) 
Amy Guigliano (310) 358-5757

University of California, San Francisco, San Francisco, CA (Nancy Lane, M.D.) 
Rosita Stuart-Thiessen (415) 206-8644

Indiana University, Indianapolis, IN (John Bradley, M.D.) 
Heather Countryman (317) 278-0555

Arthritis Research Center Foundation, Wichita, KS (Frederick Wolfe, M.D.) 
Edie Sparr (316) 263-2125 ext. 117, Cathy Urbansky (316) 263-2125 ext. 124

Hospital For Joint Diseases, New York, NY (Clifton Bingham, III, M.D.) 
Vivian Abellana (212) 598-6650

Case Western Reserve University, Cleveland, OH (Michele Hooper, M.D.) 
Mary Lesko (216) 844-6016

University of Pennsylvania, Philadelphia, PA (H. Ralph Schumacher, Jr., M.D.) 
Marie Sleck (215) 823-5979

Arthritis Consultation Center at Presbyterian Hospital of Dallas, Dallas, TX (John Cush, M.D.) 
Emma Barnboym (214) 345-8067

University of Pittsburgh, Pittsburgh, PA (Susan Manzi, M.D.) 
Michele Pauli (412) 692-4269

University of Utah, Salt Lake City, UT (Christopher Jackson, M.D.) 
Sheldon Smith (801) 581-4911

Virginia Mason Research Center, Seattle, WA (Daniel Furst, M.D.) 
Eching Voon and Amanda Mondte (206) 223-6836

University of Nebraska Medical Center, Omaha, NE (James O'Dell, M.D.) 
Ann Kinney (402) 559-3359

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What is osteoarthritis?

An estimated 21 million adults in the United States live with osteoarthritis-one of the most common types of arthritis. Osteoarthritis, also called degenerative joint disease, is caused by the breakdown of cartilage, which is the connective tissue that cushions the ends of bones within the joint. It is characterized by pain, joint damage, and limited motion. The disease generally occurs late in life, and most commonly affects the hands and large weight-bearing joints. Although the disease can impact several joints, the knees are often affected. Age, female gender, and obesity are risk factors for this condition.

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What are glucosamine and chondroitin?

Glucosamine and chondroitin are natural substances found in and around the cells of cartilage. Researchers believe these substances may help in the repair and maintenance of cartilage. In addition, researchers believe that glucosamine inhibits inflammation and stimulates cartilage cell growth, while chondroitin provides cartilage with strength and resilience. Currently, glucosamine and chondroitin are classified as dietary supplements.

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What is a dietary supplement?

A dietary supplement is a product (other than tobacco) intended to supplement the diet, which bears or contains one or more of the following dietary ingredients: a vitamin, mineral, amino acid, herb or other botanical; is intended for ingestion in the form of a capsule, powder, softgel or gelcap; and is not represented as a conventional food or as a sole item of a meal or the diet (as defined by the U.S. Dietary Supplement Health and Education Act, Oct. 25, 1994).

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What is Celecoxib?

Celecoxib (brand name Celebrex®) is a new type of nonsteroidal anti-inflammatory drug (NSAID), called a Cox-2 inhibitor. Like traditional NSAIDS, celecoxib blocks the Cox-2 enzyme in the body that stimulates inflammation. Unlike traditional NSAIDS, however, celecoxib does not block the action of Cox-1 enzyme, which is known to protect the stomach lining. As a result, celecoxib reduces joint pain and inflammation with reduced risk of gastrointestinal ulceration and bleeding.

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Resources for Further Information:

For information on complementary and alternative medicine, including research activities, conferences and events, contact the National Center for Complementary and Alternative Medicine Clearinghouse by mail at P.O. Box 8218, Silver Spring, Maryland 20907-8218, by phone at (888) 644-6226, or at its Web site .

For information on rheumatic diseases such as osteoarthritis and diseases of the musculoskeletal and skin systems, contact the National Institute of Arthritis and Musculoskeletal and Skin Diseases Information Clearinghouse by mail at NIAMS/National Institutes of Health, 1 AMS Circle, Bethesda, Maryland 20892-3675, by phone at (301) 495-4484 or at its Web site .

For information on dietary supplement labeling requirements and safety monitoring, order the FDA Guide to Dietary Supplements from the U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition at (800) FDA-4010, or visit its Web site: .

For scientific citations and abstracts on dietary supplements, visit the NIH Office of Dietary Supplements Web site at for access to the International Bibliographic Information on Dietary Supplements (IBIDS) database. This database is maintained through an interagency partnership between the NIH Office of Dietary Supplements and the U.S. Department of Agriculture, National Agricultural Library, Food and Nutrition Information Center.

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