Table 2.
Distribution of included studies based on global regional grouping, income category of country of study conduct, disease area, study sponsorship, and time period of publication
| Distribution based on | Number of studies | Proportion (%) |
|---|---|---|
| Regiona | 208 | |
| North America | 51 | 25 |
| Europe and Central Asia | 109 | 52 |
| Latin America and Caribbean | 13 | 6 |
| Middle East and North Africa | 6 | 3 |
| South Asia, East Asia, and Pacific | 25 | 12 |
| Sub-Saharan Africa | 2 | 1 |
| Not reported | 2 | 1 |
| Income category | 208 | |
| High income | 165 | 79 |
| Upper-middle income | 32 | 15 |
| Lower-middle income | 9 | 4 |
| Not reported | 2 | 1 |
| Disease area | 208 | |
| Immunology | 55 | 26 |
| Central nervous system/psychiatry | 42 | 20 |
| Cardiovascular and metabolic | 33 | 16 |
| Oncology | 25 | 12 |
| Others | 53 | 25 |
| Study sponsorb | 208 | |
| Pharma | 107 | 51 |
| Non-pharma | 95 | 46 |
| Information not available | 6 | 3 |
| Time period of study publication | 208 | |
| January 2010–December 2012 | 66 | 32 |
| January 2013–December 2014 | 40 | 19 |
| January 2015–December 2016 | 44 | 21 |
| January 2017–December 2018 | 40 | 19 |
| January 2019–October 2019 | 18 | 9 |
aThe region groups for the countries are based on the 2019 list by the World Bank
bType of sponsor was based on the funding disclosures and author affiliations. If a study was funded by a pharmaceutical company or if any of the authors were employees of a pharmaceutical company, it was labeled as pharma sponsored