Table 3.
Regression model predicting variability in response rates in placebo groups of clinical trials; n = 153 studies/comparisons; formal and diagnostic variables (ICD coding)
| Beta | t (DFs = 142) | p-value | |
| Constant | 2.07 | 0.04 | |
| Duration in months | 0.31 | 6.17 | <0.000001 |
| Multicenter trial | 0.13 | 3.04 | 0.003 |
| Quality Index | 0.18 | 3.44 | 0.0008 |
| Neoplasms (C) | -0.21 | -5.48 | <0.000001 |
| Organical psychological disorders (F0) | -0.12 | -3.24 | 0.001 |
| Disorders due to substance abuse (F1) | -0.14 | -2.97 | 0.003 |
| Nervous diseases (G) | -0.10 | -2.55 | 0.01 |
| Prevention trial | 0.44 | 7.94 | <0.000001 |
| Quality rating: Additional treatment described? | -0.21 | -4.34 | 0.00003 |
| Quality rating: Dropouts described? | -0.16 | -3.33 | 0.001 |