Table 2 Key characteristics of included RCTs and methods for handling missing data
|  | The Lancet (n = 51) | NEJM (n = 67) | Total (n = 118) | |||
|---|---|---|---|---|---|---|
Type of Intervention | ||||||
 Behaviour (diet, exercise, cognitive) | 5 | 10% | 4 | 6% | 9 | 8% |
 Medical device | 6 | 12% | 1 | 1% | 7 | 6% |
 Diagnostic | 2 | 4% | 0 | 0% | 2 | 2% |
 Drug | 19 | 37% | 47 | 70% | 66 | 56% |
 Health service strategies | 5 | 10% | 2 | 3% | 7 | 6% |
 Psychological | 5 | 10% | 0 | 0% | 5 | 4% |
 Surgical | 9 | 18% | 13 | 19% | 22 | 19% |
Number of Participants | ||||||
  < 100 | 2 | 4% | 4 | 6% | 6 | 5% |
 100 to 499 | 24 | 47% | 20 | 30% | 44 | 37% |
 500 to 999 | 16 | 31% | 21 | 31% | 37 | 31% |
 1000 to 4999 | 8 | 16% | 14 | 21% | 22 | 19% |
  ≥ 5000 | 1 | 2% | 8 | 12% | 9 | 8% |
Proportion of Missing Primary Outcome Data | ||||||
  < 10% | 21 | 41% | 33 | 49% | 54 | 46% |
 10 to 19% | 17 | 33% | 23 | 34% | 40 | 34% |
 20 to 29% | 6 | 12% | 4 | 6% | 10 | 8% |
  ≥ 30% | 3 | 6% | 4 | 6% | 7 | 6% |
 not clear | 4 | 8% | 3 | 4% | 7 | 6% |
Type of Primary Outcome | ||||||
 Binary | 20 | 39% | 34 | 51% | 54 | 46% |
 Continuous | 27 | 53% | 30 | 45% | 57 | 48% |
 Count | 4 | 8% | 0 | 0% | 4 | 3% |
 Time-to-event | 0 | 0% | 3 | 4% | 3 | 3% |
Assessed Differences Between Participants with Complete and Incomplete Data | ||||||
 Yes | 5 | 10% | 6 | 9% | 11 | 9% |
 No | 46 | 90% | 61 | 91% | 107 | 91% |
Method of Handling Missing Data in Primary Analysis | ||||||
 MAR MIa | 22 | 44% | 21 | 31% | 43 | 36% |
 Controlled MI | 1 | 2% | 1 | 1% | 2 | 2% |
 Complete case | 19 | 38% | 39 | 57% | 58 | 49% |
 Single imputation | 5 | 10% | 5 | 7% | 10 | 8% |
 Last observation carried forward | 3 | 6% | 2 | 3% | 5 | 4% |
Conducted Missing Data Sensitivity Analysis | ||||||
 Yes | 36 | 71% | 59 | 88% | 95 | 81% |
 No | 15 | 29% | 8 | 12% | 23 | 19% |
Method of Handling Missing Data in Sensitivity Analysis Where Sensitivity Was Conductedb | ||||||
 MAR MI | 28 | 68% | 42 | 54% | 70 | 59% |
 Controlled MI | 3 | 7% | 11 | 14% | 14 | 12% |
 Complete case | 6 | 15% | 10 | 13% | 16 | 13% |
 Single imputation | 1 | 2% | 8 | 10% | 9 | 8% |
 Last observation carried forward | 1 | 2% | 6 | 8% | 7 | 6% |
 Others | 2 | 5% | 1 | 1% | 3 | 3% |
Method of Controlled MI (primary or sensitivity analysis) | ||||||
 Reference-based | 2 | 40% | 5 | 45% | 7 | 44% |
 Delta-based | 3 | 60% | 6 | 55% | 9 | 56% |