July 2, 2007 Patients with osteoarthritis (OA) and rheumatoid arthritis (RA) face different treatment options and determining which ones to try can be confusing. Two new studies published in the July 2007 issue of Arthritis & Rheumatism examined patients' decisions regarding therapy for RA and glucosamine for OA and found that most RA patients are reluctant to change their treatment as long as their condition didn't worsen, and that there are discrepancies in clinical trial results for glucosamine.
Recent advances in RA treatment include multi-drug therapy with anitrheumatic drugs such as methotrexate, as well as improved tools for measuring the response to therapy. Although high-dose aggressive therapy seems to hold promise, patients' decisions often do not follow this recommendation. Frederick Wolfe and Kaleb Michaud, of the National Data Bank for Rheumatic Diseases in Wichita, KS, queried over 6,000 RA patients about their acceptance and satisfaction with therapy, their willingness to change and their reasons for not changing.
They found that more than three-quarters were satisfied with their medications and almost 64 percent would not want to change therapy as long as their condition didn't get worse. Fear of loss of control over their condition and fear of side effects emerged as major concerns, and maintaining their current status, as opposed to future improvement, appeared to be a high priority for patients. Interestingly, 71 percent of those satisfied with their therapy had moderate or greater arthritis activity according to the Patient Activity Scale. "These data indicate that there is an important discrepancy between declared satisfaction with therapy and measured activity and functional status, and that clinical activity is not an adequate explanation for satisfaction with therapy," the authors state.
In another study led by Steven C. Vlad of Boston University Medical Center in Boston, MA, researchers analyzed 15 double-blind, randomized, placebo-controlled trials of glucosamine for OA pain that were reported between 1980 and 2006. Glucosamine is classified as a dietary supplement in the U.S., is widely available, and appears to be safe but its efficacy is uncertain, with some trials reporting little effect and others reporting positive results.
The authors attempted to identify factors that explain these differing results and found that glucosamine hydrochloride, as opposed to glucosamine sulfate, has no effect on pain. Among the 12 glucosamine sulfate trials, only two were not funded by industry, and like trials of glucosamine hydrochloride, both showed no effect on pain. Industry involvement appeared to be the strongest predictor of trial results which suggested that industry bias accounted for the results of these studies and not treatment efficacy. Trials using preparations by Rottapharm had an especially large effect compared with other studies and this may be due to bias or possibly to unique efficacy of the Rotta formulation. Allocation concealment, (which attempts to prevent selection bias) was the only other factor that had a major impact, with trials that had adequate allocation concealment showing no glucosamine efficacy. Although trials with industry involvement were more likely to have positive results, they still had varied outcomes (heterogeneity); this may be due to differences in formulations or dosages, although trials using only Rottapharm products also had varying outcomes. "Among glucosamine sulfate trials, enough heterogeneity existed such that no definitive conclusion about efficacy is possible," the authors state. However, industry bias remains the most likely explanation for the positive results of some studies whereas others show no efficacy.
In an accompanying editorial in the same issue, Jean-Yves Reginster of the WHO Collaborating Center for Public Health Aspects of Rheumatic Disease in Liège, Belgium, finds the conclusions of the Vlad report to be "inaccurate and misleading." The author points out that trials by pharmaceutical companies are designed to avoid the influence of confounders that could distort the true effect of the product being tested, and they are of a high quality since they must adhere to high standards in terms of study design, analysis and reporting. He also maintains that heterogeneity is common in meta-analyses of drug trials in OA, and is usually handled by subgrouping the trials based on common characteristics, which was not done in the Vlad study. Regarding the studies that showed no effects, the author notes that they used unknown formulations of the dietary supplement glucosamine, whose inconsistency is well recognized. He notes that an analysis of three pivotal Rottapharm studies (two of which were performed by Reginster and his colleagues) showed results that were consistent and as clinically valid as other OA treatments. "Scientists should be careful when interpreting studies such as the one by Vlad and colleagues," Reginster concludes, adding that all forms of conflict by pharmaceutical companies and independent investigators should be assessed.
"The Efficacy of Glucosamine Sulfate in Osteoarthritis: Financial and Nonfinancial Conflict of Interest," Jean-Yves Reginster, Arthritis & Rheumatism, July 2007; (DOI: 10.1002/art.22852).
"Glucosamine for Pain in Osteoarthritis: Why Do Trial Results Differ"" Steven C. Vlad, Michael P. LaValley, Timothy E. McAlindon, David T. Felson, Arthritis & Rheumatism, July 2007; (DOI: 10.1002/art.22728).
"Resistance of Rheumatoid Arthritis Patients to Changing Therapy: Discordance Between Disease Activity and Patients' Treatment Choices," Frederick Wolfe and Kaleb Michaud, Arthritis & Rheumatism, July 2007; (DOI: 10.1002/art.22719).
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