Table 2.
General characteristics of included studies (N=17)
| n (%) | |
| Study design | |
| Survey of posts | 13 (76) |
| Median sample size (IQR) | 159 (879) |
| Survey of individuals or accounts | 4 (24) |
| Median sample size (IQR) | 117 (205) |
| Funding of the study | |
| Funded | 4 (24) |
| Not funded | 6 (35) |
| Not reported | 7 (41) |
| Conflict of interest of study authors | |
| Conflict of interest reported | 5 (29) |
| No conflict of interest | 11 (65) |
| Not reported | 1 (6) |
| Study focused on a specific health specialty | 12 (71) |
| Type of social media | |
| 5 (29) | |
| Blogs | 5 (29) |
| YouTube | 5 (29) |
| Not specified | 2 (12) |
| Language of posts* | |
| English | 15 (88) |
| Other languages | 4 (24) |
| No language restriction | 1 (6) |
| Time period covered | |
| ≤1 year | 4 (24) |
| 11–12 years | 4 (24) |
| Not specified | 9 (53) |
| Median year of post date (IQR) | 2018 (3) |
| Country of the subjects of study* | |
| USA | 7 (41) |
| Canada | 2 (12) |
| Europe | 2 (12) |
| Asia | 2 (12) |
| UK | 1 (6) |
| Australia | 2 (12) |
| Not reported | 6 (35) |
| No restrictions to countries | 1 (6) |
| Outcome* | |
| Prevalence of COI | 5 (29) |
| Frequency of reporting of COI | 8 (47) |
| Proportion of undisclosed COI | 3 (18) |
| Proportion of organisations reporting undisclosed COI | 2 (12) |
| Association between COI and post content | 2 (12) |
*Some studies included more than one language, country or outcome.
COI, conflicts of interest; IQR, Interquartile range; UK, United Kingdom; USA, United States of America.