Evaluation of spin in the abstracts of systematic reviews and meta-analyses related to the treatment of proximal humeral fractures

Background: Research has shown that many physicians rely solely on abstracts to make clinical decisions. However, many abstracts have been shown to be misleading. The primary objective of this study was to identify the prevalence of spin—bias toward particular results—within the abstracts of systematic reviews and meta-analyses pertaining to the treatment of proximal humeral fractures, one of the most common osteoporotic fractures among elderly patients. 

Methods: We systematically searched the MEDLINE and Embase databases to identify systematic reviews and meta-analyses examining the treatment of proximal humeral fractures. Screening and data extraction occurred in a masked, duplicate fashion. The 9 most severe types of spin that occur within abstracts were extracted, along with study characteristics, including journal recommendations to adhere to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines and year in which the review was performed, to identify potential associations. We subsequently explored the association between spin and the methodologic quality of a systematic review using the revised A Measurement Tool to Assess Systematic Reviews (AMSTAR 2) appraisal instrument. 

Results: Our search retrieved 505 articles, among which 73 systematic reviews met the inclusion criteria. We found that 34.2% of the included systematic reviews (25 of 73) contained spin. Spin type 3 (“selective reporting of or overemphasis on efficacy outcomes or analysis favoring the beneficial effect of the experimental intervention”) was the most common type identified (12 of 73, 16.4%). Three spin types were not identified in any of the abstracts. Spin was 3.2 (odds ratio, 3.2; 95% confidence interval, 1.02-10.02) times more likely to be present in systematic reviews published in journals recommending adherence to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Furthermore, the odds of an abstract containing spin was 1.25 (odds ratio, 1.25; 95% confidence interval, 1.02-1.52) times more likely in systematic reviews for each year after 2000. No other study characteristics were associated with spin. The methodologic quality was rated as critically low in 24 studies (32.9%), low in 14 (19.2%), moderate in 28 (38.4%), and high in 7 (9.6%), but these findings were not associated with spin. 

Conclusion: Spin was present in systematic review abstracts regarding the treatment of proximal humeral fractures. Measures such as education on the subject of spin and improved reporting standards should be implemented to increase awareness and reduce the incidence of spin in abstracts.