Industry sponsorship and publication bias among animal studies evaluating the effects of statins on atherosclerosis and bone outcomes: a meta-analysis.

Andrew T Anglemyer,Lisa Bero,David Krauth

doi:10.1186/s12874-015-0008-z

Abstract

BackgroundThe effect that sponsorship has on publication rates or overall effect estimates in animal studies is unclear, though methodological biases are prevalent in animal studies of statins and there may be differences in efficacy estimates between industry and non-industry sponsored studies. In the present analysis, we evaluated the impact of funding source on publication bias in animal studies estimating the effect of statins on atherosclerosis and bone outcomes.MethodsWe conducted two independent systematic reviews and meta-analyses identifying animal studies evaluating the effect of statins on reducing the risk of atherosclerosis outcomes (n = 49) and increasing the likelihood of beneficial bone outcomes (n = 45). After stratifying the included studies within each systematic review by funding source, three separate analyses were employed to assess publication bias in these meta-analyses—funnel plots, Egger’s Linear Regression, and the Trim and Fill methods.ResultsWe found potential evidence of publication bias, primarily in non-industry sponsored studies. In all 3 assessments of publication bias, we found evidence of publication bias in non-industry sponsored studies, while in industry-sponsored studies publication bias was not evident in funnel plots and Egger’s regression tests. We also found that inadequate reporting of sponsorship in animal studies is still exceedingly common.ConclusionsIn meta-analyses assessing the effects of statins on atherosclerosis and bone outcomes in animal studies, we found evidence of publication bias, though small numbers of industry-sponsored studies limit the interpretation of the trim-and-fill results. This publication bias is more prominent in non-industry sponsored studies. Industry and non-industry funded researchers may have different incentives for publication. Industry may have a financial interest to publish all preclinical animal studies to maximize the success of subsequent trials in humans, whereas non-industry funded academics may prefer to publish high impact statistically significant results only. Differences in previously published effect estimates between industry- and non-industry sponsored animal studies may be partially explained by publication bias.Electronic supplementary materialThe online version of this article (doi:10.1186/s12874-015-0008-z) contains supplementary material, which is available to authorized users.

Highlights

The effect that sponsorship has on publication rates or overall effect estimates in animal studies is unclear, though methodological biases are prevalent in animal studies of statins and there may be differences in efficacy estimates between industry and non-industry sponsored studies
We identified 49 unique studies evaluating 184 atherosclerosis outcomes in 3498 animals and the pooled effect was standardized mean difference (SMD) = −1.25 with substantial heterogeneity (I2 = 73%) (Table 1)
We identified 45 unique studies evaluating 654 beneficial bone outcomes in 1986 animals and the pooled effect was SMD = 0.42 with substantial heterogeneity (I2 = 89%)

Summary

Introduction

The effect that sponsorship has on publication rates or overall effect estimates in animal studies is unclear, though methodological biases are prevalent in animal studies of statins and there may be differences in efficacy estimates between industry and non-industry sponsored studies. We evaluated the impact of funding source on publication bias in animal studies estimating the effect of statins on atherosclerosis and bone outcomes. Valid animal research data can generate and test important clinical hypotheses, minimizing the potential risk to patients in clinical trials. Studies of human disease are often developed and improved upon as the result of animal research. Prior research suggests that there may be a weak correlation between results in animals studies and subsequent human trials [1,2,3,4]. The differences between the results from animal research and human studies may be partially explained by reporting bias in animal studies [5]. Publication bias is estimated using a variety of qualitative and quantitative methods, including funnel plots, Egger regression tests for funnel plot asymmetry, and trim-and-fill methods [13]

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Results

Discussion

Conclusion