Evaluating the Quality of Articles Published in Journal Supplements Compared With the Quality of Those Published in the Parent Journal

Rochon, Paula A.; Gurwitz, Jerry H.; Cheung, Christian P.; Hayes, Jason; Chalmers, Thomas C.

doi:10.1001/jama.1994.03520020034009

Cited by 107 publications

(63 citation statements)

References 26 publications

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“…We included measures of trial quality, including the Jadad score (27), the percentage of subjects withdrawing from the trial (28), the presence of an intent-to-treat analysis (28), and the presence of adequate allocation concealment. Allocation concealment was measured as adequate, intermediate, or inadequate according to Rochon et al (28). If an article described a process by which the next treatment assigned to a patient was impossible to predict, it was labeled "adequate."…”

Section: Exploration Of Heterogeneitymentioning

confidence: 99%

Glucosamine for pain in osteoarthritis: Why do trial results differ?

Vlad

LaValley

McAlindon

et al. 2007

Arthritis & Rheumatism

175

124

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Objective. Investigators in trials of glucosamine report a range of estimates for efficacy, making conclusions difficult. We undertook this study to identify factors that explain heterogeneity in trials of glucosamine.Methods. We searched for reports of trial results in Ovid Medline, the Cochrane Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews, and proceedings of scientific conferences. We selected reports of randomized, double-blind, placebocontrolled trials of glucosamine for pain from osteoarthritis of the knee or hip. We extracted data regarding features of design, subjects, and markers of industry involvement, including industry funding, whether a drug was supplied by industry, industry participation, and industry-affiliated authorship. We examined which factors best accounted for differences in the effect sizes of studies grouped by these characteristics, and we examined changes in I 2 , a measure of heterogeneity. Results. Fifteen trials met our inclusion criteria. The summary effect size was 0.35 (95% confidence interval 0.14, 0.56). I 2 was 0.80. Except for allocation concealment, no feature of study design explained this substantial heterogeneity. Summary effect sizes ranged from 0.05 to 0.16 in trials without industry involvement, but the range was 0.47-0.55 in trials with industry involvement. The effect size was 0.06 for trials using glucosamine hydrochloride and 0.44 for trials using glucosamine sulfate. Trials using Rottapharm products had an effect size of 0.55, compared with 0.11 for the rest.Conclusion. Heterogeneity among trials of glucosamine is larger than would be expected by chance. Glucosamine hydrochloride is not effective. Among trials with industry involvement, effect sizes were consistently higher. Potential explanations include different glucosamine preparations, inadequate allocation concealment, and industry bias.Osteoarthritis (OA) is one of the most common chronic diseases affecting Americans and is a major source of disability in elderly persons (1). Pharmacologic therapy for pain relief is widely perceived to be the backbone of effective management. Unfortunately, many of the most effective pain relievers, especially nonsteroidal antiinflammatory drugs, have well-known side effects that limit their use.Glucosamine, which is classified as a "dietary supplement" in the US and is available over the counter, appears to be safe and is widely marketed for pain relief in OA. However, its efficacy is uncertain. While several trials have suggested that glucosamine has a marginal, if any, effect compared with placebo, others report robust efficacy.In a series of trials using similar methods and subjects, we would expect random variation in the estimate of the true effect of an intervention. If the observed variation in outcomes from trial to trial is consistent with chance variation, then the trials are said to be homogeneous (i.e., the trials are all evaluating the same effect and their conclusions are similar). If the observed variation in outcomes is...

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Section: Exploration Of Heterogeneitymentioning

confidence: 99%

Glucosamine for pain in osteoarthritis: Why do trial results differ?

Vlad

LaValley

McAlindon

et al. 2007

Arthritis & Rheumatism

175

124

View full text Add to dashboard Cite

show abstract

“…While this approach is appropriate, they selectively assigned an "intermediate" or even "inadequate" label to some of the most important Rottapharm trials by misusing, not by misinterpreting, the method of Rochon et al (39), or by using data published in an abstract for the GUIDE trial, although a high-quality full-length report was about to be published (4).…”

Section: Principles For a Sound Systematic Review And Metaanalysis Ofmentioning

confidence: 99%

The efficacy of glucosamine sulfate in osteoarthritis: Financial and nonfinancial conflict of interest

Reginster¹

2007

Arthritis & Rheumatism

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“…Supplements can also be lucrative and many specialty journals welcome or solicit them, often accepting lower-quality articles. 13,14 While the publisher would never interfere in the editorial processes of the journal, when I mentioned the idea of an accompanying editorial they reminded me that it was important to be diplomatic with all parties concerned, given the financial realities faced by many small publishers. As is our usual practice, our commercial department had already notified the manufacturer of the drug about the article and they had expressed interest in purchasing reprints.…”

Section: Seeking Editorial Guidancementioning

confidence: 99%

The pharmaceutical industry, researchers and publishers: the realities of competing interests within specialty journals

Irving¹

2005

Learned Publishing

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Evaluating the Quality of Articles Published in Journal Supplements Compared With the Quality of Those Published in the Parent Journal

Cited by 107 publications

References 26 publications

Glucosamine for pain in osteoarthritis: Why do trial results differ?

Glucosamine for pain in osteoarthritis: Why do trial results differ?

The efficacy of glucosamine sulfate in osteoarthritis: Financial and nonfinancial conflict of interest

The pharmaceutical industry, researchers and publishers: the realities of competing interests within specialty journals

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