Table 3 Types of spin in reviews that did or did not seek adverse effects of interventions

Misleading reporting (in the abstract) on adverse effects of interventions:

“Incomplete or inadequate reporting in the abstract on the results of adverse effects that were not supported by the findings of the review.”

Categories:

1) Not reporting in the abstract on the results of adverse effects found in the review.

2) Selective reporting in the abstract on the results of adverse effects found in the review.

Categories:

1) Reporting on results of adverse effects in the abstract when adverse effects were not sought.

2) Reporting in the abstract that adverse effects were sought when they were not sought.

Misleading interpretation (in the abstract) on adverse effects of interventions:

“Interpretation in the abstract on the results of adverse effects that was not supported by the findings of the review.” This could for example underestimated the adverse effects of the intervention.

Categories:

1) Claiming in the abstract that the intervention is safe (has no or minimal adverse effects), despite concerning results on adverse effects found in the review, e.g., based on non-statistically significant results on adverse effects with wide confidence intervals [27].

2) Downgrading in the abstract the importance of the adverse effects, despite concerning results on adverse effects found in the review.

3) Recommendations are made in the abstract for clinical practice that are not supported by the findings in the review on adverse effects [27].

Categories:

1) Claiming in the abstract that the intervention is safe (has no or minimal adverse effects) despite not having sought adverse effects.

2) Downgrading in the abstract the importance of the adverse effects, despite not having sought adverse effects.

3) Recommendations are made in the abstract for clinical practice despite not having sought adverse effects.

Misleading (inappropriate) extrapolation (in the abstract) on adverse effects of interventions:

“Overgeneralisation in the abstract of the study results to different populations, interventions, outcomes or settings than were assessed in the review despite evidence on adverse effects on a different population, intervention, outcome or setting.”

Categories:

1) Results are extrapolated in the abstract to another population, intervention, outcome, or setting than were assessed in the review despite evidence on adverse effects on a different population, intervention, outcome, or setting.

Categories:

1) Results are extrapolated in the abstract to another population, intervention, outcome, or setting than were assessed in the review despite not having sought adverse effects.