Table 2. Comparison of Matched Pairs of Interim and Final Publications Both Reporting the Same Efficacy or Safety Outcomes and Examples of Changes in Abstract Conclusions Between Interim and Final Publications (n = 73)a.
| Characteristics | Publication | Difference, % (95% CI) |
P Valueb | |
|---|---|---|---|---|
| Interim | Final | |||
| Trial participants | ||||
| No. of participants, median (IQR) | 205 (89-544) | 295 (100-724) | <.001 | |
| ≤50 participants, No. (%) | 8 (11) | 5 (5) | 6 (−1 to 12) | .05 |
| Follow-up time, wk | ||||
| Median (IQR) | 48 (22-81) | 104 (52-156) | <.001 | |
| ≤4, No. (%) | 11 (15) | 5 (7) | 8 (1 to 16) | .03 |
| Journal prominence | ||||
| High impact factor (≥20), No. (%) | 16 (22) | 17 (23) | 1 (−8 to 11) | .70 |
| Top-5 impact factor for general medical journal, No. (%) | 10 (14) | 8 (11) | 3 (13 to 8) | .60 |
| Both interim and final publications in top-5 journal, No. (%) | 3 (4) | |||
| Altmetric attention score, median (IQR)c | 6 (2-20) | 5 (2-25) | .10 | |
| Examples of changes in abstract conclusiond | ||||
| Not different → beneficial | Abiraterone showed a trend toward improved overall survival in patients with metastatic castration–resistant prostate cancer (Lancet Oncology). | Treatment with abiraterone acetate prolonged overall survival vs prednisone alone by a margin that was both clinically and statistically significant (New England Journal of Medicine; NCT00887198). | ||
| Not different → harmful (or possibly harmful) | The everolimus-eluting bioresorbable scaffold (Absorb) showed similar 1-year composite secondary clinical outcomes as the everolimus-eluting metallic stent (Lancet). | A higher rate of device-oriented composite end point due to target vessel myocardial infarction, including periprocedural myocardial infarction, was observed in the everolimus-eluting bioresorbable scaffold (Absorb) group (Lancet; NCT01425281). | ||
| Beneficial → not different | The capecitabine-containing chemotherapy regimen reduced breast cancer recurrence vs a control schedule of standard agents (Lancet Oncology). | Integration of capecitabine into a regimen that contains docetaxel, epirubicin, and cyclophosphamide did not improve recurrence-free survival significantly vs a similar regimen without capecitabine (Journal of Clinical Oncology; NCT00114816). | ||
| Beneficial → harmful | First randomized phase 3 trial in patients with pretreated chronic-phase chronic myeloid leukemia demonstrating improvements in major cytogenetic response to complete cytogenetic response and major molecular response rates with high-dose imatinib therapy (Haematologica). | Standard-dose imatinib remains the standard of care for pretreated patients with chronic-phase chronic myeloid leukemia (high-dose imatinib reduced event-free survival) (Haematologica; NCT00327262). | ||
| Inconclusive → noninferior | The noninferiority criterion was not met and overall survival results were inconclusive (Lancet Oncology). | Bevacizumab plus capecitabine for HER2-negative locally recurrent or metastatic breast cancer offering good tolerability without compromising overall survival vs bevacizumab plus paclitaxel (Lancet Oncology; NCT00600340). | ||
Abbreviation: IQR, interquartile range.
Percentages may not add to total because of rounding.
P values for paired differences (McNemar test for dichotomous variables and signed rank test for continuous variables).
Altmetric attention scores were available for 37 interim and 48 final publications.
Not different indicates that the intervention is not statistically significantly different than placebo or meets noninferiority criterion for active control. Beneficial indicates that the intervention is statistically significantly better than placebo or active control. Harmful indicates that the intervention is statistically significantly worse than placebo or active control (1 of the 3 pairs of publications that changed from not different to harmful was possibly harmful because it had a P = .05, but the abstract conclusion raised concern about a possible increase in deaths due to the intervention).