Number of papers published in BMJ Open in 2020 in each research topic with ≥50 papers, and proportion of these with PPI
| Research topic | n | % of total | Mean % PPI (95% CI) |
| Mental health | 149 | 5.0 | 36.9 (29.1 to 44.7) |
| Qualitative research | 51 | 1.7 | 35.3 (22.0 to 48.5) |
| Health services research | 168 | 5.6 | 31.0 (23.9 to 38.0) |
| Neurology | 82 | 2.7 | 29.3 (19.4 to 39.2) |
| Surgery | 102 | 3.4 | 28.4 (19.6 to 37.2) |
| Rehabilitation medicine | 65 | 2.2 | 26.2 (15.4 to 36.9) |
| Oncology | 88 | 2.9 | 25.0 (15.9 to 34.1) |
| Cardiovascular medicine | 120 | 4.0 | 24.2 (16.5 to 31.9) |
| Paediatrics | 91 | 3.0 | 23.1 (14.4 to 31.8) |
| Diabetes and endocrinology | 85 | 2.8 | 22.4 (13.4 to 31.3) |
| Obstetrics and gynaecology | 98 | 3.3 | 21.4 (13.3 to 29.6) |
| Emergency medicine | 66 | 2.2 | 21.2 (11.3 to 31.2) |
| General practice/family practice | 94 | 3.1 | 20.2 (12.0 to 28.4) |
| Public health | 366 | 12.2 | 16.1 (12.3 to 19.9) |
| Infectious diseases | 79 | 2.6 | 15.2 (7.2 to 23.2) |
| Global health | 97 | 3.2 | 13.4 (6.6 to 20.2) |
| Health economics | 61 | 2.0 | 6.6 (0.3 to 12.8) |
| Epidemiology | 241 | 8.0 | 6.2 (3.2 to 9.3) |
| Medical education and training | 58 | 1.9 | 3.4 (−1.3 to 8.2) |
|   | 1261 | 71.8 |
PPI, patient and public involvement.