Table 1.
Summary of Studies Included in the Analysis.
| Analysis period | ||||||
|---|---|---|---|---|---|---|
| Period 1 | Period 2 | |||||
| N | M (SD) | N | M (SD) | t stat a | P-value a | |
| Study Type | ||||||
| Interventional | 120 | 20 (5.2) | 183 | 30.5 (7.8) | 3.02 | .013 |
| Observational | 1 | 0.2 (0.4) | 11 | 1.8 (1.4) | 3.30 | .016 |
| All studies | 121 | 21.2 (5.3) | 194 | 32.3 (6.4) | 3.25 | .009 |
| Study Phase | ||||||
| Phase 1 | 10 | 1.7 (1.6) | 16 | 2.7 (2.2) | 0.82 | .43 |
| Phase 2 | 31 | 5.2 (3.5) | 70 | 11.7 (2.8) | 3.25 | .009 |
| Phase 3 | 13 | 2.2 (1.1) | 35 | 5.8 (1.6) | 4.31 | .002 |
| Phase 4 | 56 | 9.3 (1.9) | 46 | 7.7 (1.6) | 1.51 | .16 |
| Not Applicable/Not Specified | 11 | 1.8 (2.1) | 27 | 4.5 (3.4) | 1.49 | .17 |
| Study Population | ||||||
| Adult Only | 109 | 18.2 (5.3) | 153 | 25.5 (7.1) | 2.23 | .05 |
| Pediatric Only | 1 | 0.2 (0.4) | 9 | 1.5 (1.0) | 2.90 | .025 |
| Pediatric and Adult | 11 | 1.8 (1.1) | 32 | 5.3 (2.0) | 3.49 | .009 |
| Funding Type | ||||||
| Nonindustry-Funded | 60 | 10 (3.7) | 108 | 18 (3.6) | 3.49 | .006 |
| Industry-Funded | 37 | 6.2 (1.6) | 66 | 11 (3.4) | 2.87 | .023 |
| Combination Funded | 24 | 4 (1.8) | 20 | 3.3 (2.9) | 0.57 | .58 |
a
Two-tailed t test assuming unequal variances.