Table 1.
Rates of Publication and Citation and Costs of Groups of Clinical Trials.
| Variable | No. of Trials |
Median Time to Publication |
Proportion of Trials Published |
Unadjusted Rate Ratio for Likelihood of Publication (95% CI) |
Cost to NHLBI |
Annual Citation Rate* |
||
|---|---|---|---|---|---|---|---|---|
| Within 12 mo |
Within 30 mo |
Within 48 mo |
||||||
| mo | percent | $ million | ||||||
| All trials | 244 | 25 | 23 | 57 | 75 | — | 2,021 | 56 |
| Clinical-event end point | ||||||||
| Yes | 45 | 9 | 64 | 95 | 100 | 5.47 (3.74–7.98) | 1,381 | 135 |
| No | 199 | 31 | 12 | 48 | 68 | Reference | 640 | 13 |
| Cost | ||||||||
| ≥$5 million | 60 | 9 | 63 | 91 | 97 | 4.92 (3.49–6.95) | 1,595 | 117 |
| <$5 million | 184 | 35 | 9 | 45 | 66 | Reference | 427 | 10 |
| Multiple awards | ||||||||
| Yes | 37 | 8 | 62 | 92 | 95 | 3.68 (2.52–5.38) | 1,303 | 139 |
| No | 207 | 30 | 15 | 50 | 71 | Reference | 718 | 30 |
| Contract or cooperative agreement | ||||||||
| Yes | 64 | 11 | 55 | 83 | 90 | 2.81 (2.02–3.90) | 1,560 | 113 |
| No | 180 | 31 | 11 | 48 | 69 | Reference | 461 | 14 |
| Sample size | ||||||||
| ≥1000 participants | 49 | 11 | 54 | 88 | 96 | 3.87 (2.38–6.30) | 1,426 | 134 |
| 150–999 participants | 134 | 30 | 14 | 50 | 71 | 1.14 (0.94–1.74) | 466 | 16 |
| <150 participants | 61 | 30 | 14 | 49 | 65 | Reference | 129 | 20 |
| Behavioral intervention | ||||||||
| Yes | 135 | 32 | 11 | 48 | 72 | 0.59 (0.43–0.81) | 932 | 18 |
| No | 109 | 20 | 36 | 68 | 80 | Reference | 1,089 | 79 |
| Cluster randomization | ||||||||
| Yes | 46 | 29 | 5 | 55 | 65 | 0.72 (0.47–1.10) | 174 | 11 |
| No | 198 | 24 | 27 | 58 | 77 | Reference | 1,848 | 61 |
| Positive outcome | ||||||||
| All trials† | ||||||||
| Yes | 98 | 23 | 22 | 57 | 76 | 1.06 (0.77–1.45) | 363 | 29 |
| No | 134 | 25 | 24 | 60 | 77 | Reference | 1,634 | 73 |
| Trials completed before January 1, 2010 | ||||||||
| Yes | 71 | 22 | 21 | 58 | 76 | 1.13 (0.80–1.58) | 287 | 30 |
| No | 97 | 25 | 23 | 59 | 77 | Reference | 1,419 | 75 |
| Clinical-event end point and cost ≥$5 million | ||||||||
| Both | 37 | 9 | 70 | 97 | 100 | 7.55 (4.99–11.42) | 1,356 | 154 |
| Positive outcome | 6 | 7 | 83 | 100 | 100 | 47 | 134 | |
| Negative outcome | 31 | 9 | 68 | 97 | 100 | 1,309 | 158 | |
| One | 31 | 15 | 46 | 79 | 92 | 3.46 (2.22–5.41) | 264 | 32 |
| Positive outcome | 12 | 9 | 53 | 76 | 84 | 145 | 35 | |
| Negative outcome | 19 | 23 | 39 | 82 | 100 | 119 | 29 | |
| Neither | 176 | 35 | 7 | 44 | 65 | Reference | 402 | 8 |
| Positive outcome | 80 | 31 | 10 | 49 | 73 | 193 | 8 | |
| Negative outcome | 84 | 36 | 5 | 41 | 61 | 184 | 8 | |
*
Shown is the average annual citation rate per published trial, which was calculated by dividing the total citations by the number of years since publication.
†
Information about 12 of the trials was insufficient to classify the outcome as positive or negative.