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The effect of journal impact factor, reporting conflicts, and reporting funding sources, on standardized effect sizes in back pain trials: a systematic review and meta-regression.

Froud R, Bjørkli T, Bright P, Rajendran D, Buchbinder R, Underwood M, Evans D, Eldridge S - BMC Musculoskelet Disord (2015)

Bottom Line: Low back pain is a common and costly health complaint for which there are several moderately effective treatments.We modelled the relationship using 5-year journal impact factor, and categories of reported of conflicts of interest, and categories of reported funding (reported none and reported some, compared to not reporting these) using meta-regression, adjusting for sample size, and publication year.The absence of associations between effect size and impact factor, reporting sources of funding, and conflicts of interest reflects positively on research and publisher conduct in the field.

View Article: PubMed Central - PubMed

Affiliation: Clinical Trials Unit, Warwick Medical School, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK. r.froud@warwick.ac.uk.

ABSTRACT

Background: Low back pain is a common and costly health complaint for which there are several moderately effective treatments. In some fields there is evidence that funder and financial conflicts are associated with trial outcomes. It is not clear whether effect sizes in back pain trials relate to journal impact factor, reporting conflicts of interest, or reporting funding.

Methods: We performed a systematic review of English-language papers reporting randomised controlled trials of treatments for non-specific low back pain, published between 2006-2012. We modelled the relationship using 5-year journal impact factor, and categories of reported of conflicts of interest, and categories of reported funding (reported none and reported some, compared to not reporting these) using meta-regression, adjusting for sample size, and publication year. We also considered whether impact factor could be predicted by the direction of outcome, or trial sample size.

Results: We could abstract data to calculate effect size in 99 of 146 trials that met our inclusion criteria. Effect size is not associated with impact factor, reporting of funding source, or reporting of conflicts of interest. However, explicitly reporting 'no trial funding' is strongly associated with larger absolute values of effect size (adjusted β=1.02 (95 % CI 0.44 to 1.59), P=0.001). Impact factor increases by 0.008 (0.004 to 0.012) per unit increase in trial sample size (P<0.001), but does not differ by reported direction of the LBP trial outcome (P=0.270).

Conclusions: The absence of associations between effect size and impact factor, reporting sources of funding, and conflicts of interest reflects positively on research and publisher conduct in the field. Strong evidence of a large association between absolute magnitude of effect size and explicit reporting of 'no funding' suggests authors of unfunded trials are likely to report larger effect sizes, notwithstanding direction. This could relate in part to quality, resources, and/or how pragmatic a trial is.

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Related in: MedlinePlus

Effect size by 2011 5-year journal impact factor. The figure shows the effect size and the variance of effect size by journal impact factor
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Fig2: Effect size by 2011 5-year journal impact factor. The figure shows the effect size and the variance of effect size by journal impact factor

Mentions: There was no evidence of an association (either linear or non-linear) between effect size and IF (P=0.527) but journals with low IFs tended to report trials with a wider range of effect sizes than high If journals (Fig. 2). Compared to nothing being reported about COIs, there was no evidence of an effect of reporting no COIs (P=0.624) or some COIs (P=0.950). Compared to nothing being reported about funding, there was no evidence of an effect of reporting no funding (P=0.481) or some funding (P=0.847). Table 2 shows full results, including both crude and adjusted beta estimates, and covariates.Fig. 2


The effect of journal impact factor, reporting conflicts, and reporting funding sources, on standardized effect sizes in back pain trials: a systematic review and meta-regression.

Froud R, Bjørkli T, Bright P, Rajendran D, Buchbinder R, Underwood M, Evans D, Eldridge S - BMC Musculoskelet Disord (2015)

Effect size by 2011 5-year journal impact factor. The figure shows the effect size and the variance of effect size by journal impact factor
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4663726&req=5

Fig2: Effect size by 2011 5-year journal impact factor. The figure shows the effect size and the variance of effect size by journal impact factor
Mentions: There was no evidence of an association (either linear or non-linear) between effect size and IF (P=0.527) but journals with low IFs tended to report trials with a wider range of effect sizes than high If journals (Fig. 2). Compared to nothing being reported about COIs, there was no evidence of an effect of reporting no COIs (P=0.624) or some COIs (P=0.950). Compared to nothing being reported about funding, there was no evidence of an effect of reporting no funding (P=0.481) or some funding (P=0.847). Table 2 shows full results, including both crude and adjusted beta estimates, and covariates.Fig. 2

Bottom Line: Low back pain is a common and costly health complaint for which there are several moderately effective treatments.We modelled the relationship using 5-year journal impact factor, and categories of reported of conflicts of interest, and categories of reported funding (reported none and reported some, compared to not reporting these) using meta-regression, adjusting for sample size, and publication year.The absence of associations between effect size and impact factor, reporting sources of funding, and conflicts of interest reflects positively on research and publisher conduct in the field.

View Article: PubMed Central - PubMed

Affiliation: Clinical Trials Unit, Warwick Medical School, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK. r.froud@warwick.ac.uk.

ABSTRACT

Background: Low back pain is a common and costly health complaint for which there are several moderately effective treatments. In some fields there is evidence that funder and financial conflicts are associated with trial outcomes. It is not clear whether effect sizes in back pain trials relate to journal impact factor, reporting conflicts of interest, or reporting funding.

Methods: We performed a systematic review of English-language papers reporting randomised controlled trials of treatments for non-specific low back pain, published between 2006-2012. We modelled the relationship using 5-year journal impact factor, and categories of reported of conflicts of interest, and categories of reported funding (reported none and reported some, compared to not reporting these) using meta-regression, adjusting for sample size, and publication year. We also considered whether impact factor could be predicted by the direction of outcome, or trial sample size.

Results: We could abstract data to calculate effect size in 99 of 146 trials that met our inclusion criteria. Effect size is not associated with impact factor, reporting of funding source, or reporting of conflicts of interest. However, explicitly reporting 'no trial funding' is strongly associated with larger absolute values of effect size (adjusted β=1.02 (95 % CI 0.44 to 1.59), P=0.001). Impact factor increases by 0.008 (0.004 to 0.012) per unit increase in trial sample size (P<0.001), but does not differ by reported direction of the LBP trial outcome (P=0.270).

Conclusions: The absence of associations between effect size and impact factor, reporting sources of funding, and conflicts of interest reflects positively on research and publisher conduct in the field. Strong evidence of a large association between absolute magnitude of effect size and explicit reporting of 'no funding' suggests authors of unfunded trials are likely to report larger effect sizes, notwithstanding direction. This could relate in part to quality, resources, and/or how pragmatic a trial is.

Show MeSH
Related in: MedlinePlus