Primary outcome: response from contacted authors
| Response | Adjusted OR (95% CI) | P value | |
| Short message and protocol | 36/45 (80%) | 1.10 (0.36 to 3.33) | 0.87 |
| Long message | 33/43 (77%) |
Adjusted for year of publication, size of trial and if the author had multiple trials included. Total N included=88. Robust SEs were used in model fitting.