Impact of industry sponsorship on the quality of systematic reviews of vaccines: a cross-sectional analysis of studies published from 2016 to 2019

Abstract

Background Systematic reviews (SRs) provide the highest level of evidence and inform evidence-based decision making in health care. Earlier studies found association with industry to be negatively associated with methodological quality of SRs. However, this has not been investigated in SRs on vaccines. Methods We performed a systematic literature search using MEDLINE and EMBASE in March 2020. The results were restricted to those published between 2016 and 2019 with no language restrictions. Study characteristics were extracted by one person and checked by an experienced reviewer. The methodological quality of the SRs was assessed with the AMSTAR 2 tool by multiple reviewers after a calibration exercise was performed. A summary score for each SR was calculated. The Mann-Whitney U test and Fisher’s exact test were performed to compare both groups. Results Out of 185 SRs that met all inclusion criteria, 27 SRs were industry funded. Those were matched with 30 non-industry funded SRs resulting in a total sample size of 57. The mean AMSTAR 2 summary score across all SRs was 0.49. Overall, the median AMSTAR 2 summary score was higher for the non-industry funded SRs than for the industry-funded SRs (0.62 vs. 0.36; p < .00001). Lower ratings for industry funded SRs were consistent across all but one AMSTAR 2 item, though significantly lower only for three specific items. Conclusion The methodological quality of SRs in vaccination is comparable to SRs in other fields, while it is still suboptimal. We are not able to provide a satisfactory explanation why industry funded SRs had a lower methodological quality than non-industry funded SRs over recent years. Industry funding is an important indicator of methodological quality for vaccine SRs and should be carefully considered when appraising SR quality.

Quality of randomized controlled trials and systematic reviews in pediatric surgery: A cross‐sectional meta‐research study

“…Notably, our findings revealed that unfunded and government‐funded reviews exhibited higher reporting quality compared to industry‐funded studies and those without declared funding, although the reasons for this observation are not immediately apparent. Previous studies have reported similar results, finding that industry‐funded systematic reviews may be associated with lower methodological quality in a number of topics, including vaccination,[37] drugs and medical devices [38] and asthma treatment [39]. Gøtzsche et al (2012) proposed that the higher quality of nonindustry reviews was due to the larger number of co‐authors who are methodologists [40].…”

Definition, harms, and prevention of redundant systematic reviews

“…We have a reporting guideline for systematic reviews and its extensions [43], as well as Cochrane's methodological expectations for systematic reviews of interventions [44], Joanna Briggs Institute (JBI) Checklist for Systematic Reviews [45], AMSTAR 2 tool for assessing methodological quality [5], a ROBIS tool for assessing the risk of bias in systematic reviews [46], etc. However, despite the existence of those tools, it has been reported in multiple studies that published systematic reviews do not adhere to guidance from those tools [47][48][49][50][51][52]. Thus, further studies in the field of research methodology should explore interventions that would improve how systematic reviews are planned, conducted, and reported.…”