Measures of treatment efficacy from the randomised controlled trials in rheumatoid arthritis (RA)*
| Etanercept v placebo2 | Drug A v placebo (a hypothetical study) | |||
|---|---|---|---|---|
| Variable | Treatment group | Placebo group | Treatment group | Placebo group |
| *Adapted from reference 7. | ||||
| AEs, adverse events | ||||
| Group size (n) | 78 | 80 | ||
| Number not met ACR50 improvement (n) | 38 | 75 | ||
| Risk for treatment failure | 0.487 (X) | 0.938 (Y) | 0.0026 (X) | 0.005 (Y) |
| Relative risk (X/Y) | 0.52 | 0.52 | ||
| Relative risk reduction ((Y−X)/Y or 1−X/Y) | 0.48 | 0.48 | ||
| Absolute risk reduction ([|]Y−X[|]) | 0.45 | 0.0024 | ||
| Number needed to treat (1/[|]Y−X[|]) | 2.2 | 416.7 | ||
| Number of withdrawals due to AEs | 2 | 3 | ||
| Risk for withdrawal | 0.026 (a) | 0.038 (b) | ||
| Number needed to harm (1/[|]b−a[|]) | 83.3 | |||