Methodological quality of RCTs in diabetes
| Patient-important outcomes | Surrogate outcomes | Physiological and other laboratory outcomes | Overall | |
|---|---|---|---|---|
| n | 42 | 38 | 119 | 199 |
| Study characteristics | ||||
| Parallel/cross-over trials | 36/6 | 31/7 | 78/41 | 145/54 |
| Study duration (weeks) | ||||
| Parallel trials | 136 (26–235) | 33 (24–129) | 16 (10–48) | 26 (12–104) |
| Cross-over trials | 24 (5–42) | 16 (1.3–51) | 12 (2.6–24) | 13 (3–27) |
| Randomized | ||||
| Parallel trials | 474 (162–1,513) | 160 (46–404) | 54 (37–105) | 97 (46–327) |
| Cross-over trials | 23 (20–27) | 35 (22–63) | 16 (9–27) | 20 (11–32) |
| Reporting | ||||
| Patient flow chart | 14 (33) | 8 (21) | 18 (15) | 40 (20) |
| IRB approval, informed consent | 40 (95) | 37 (97) | 115 (97) | 192 (97) |
| Estimation of sample size | 25 (60) | 19 (50) | 34 (29) | 78 (39) |
| Adverse events reported | 16 (38) | 21 (55) | 64 (54) | 101 (51) |
| Methods to minimize bias | ||||
| Adequate allocation concealment | 9 (21) | 4 (11) | 8 (7) | 21 (11) |
| Blinding | ||||
| Participants | 20 (48) | 17 (45) | 62 (52) | 99 (50) |
| Health care providers | 19 (45) | 20 (53) | 52 (44) | 91 (46) |
| Data collectors | 9 (21) | 3 (8) | 11 (9) | 23 (12) |
| Data analysts | 3 (7) | 1 (3) | 7 (6) | 11 (6) |
| Judicial assessors of outcomes | 8 (19) | 1 (3) | 8 (7) | 17 (9) |
| Only described as double blind | 16 (38) | 16 (42) | 57 (48) | 89 (45) |
| Intention-to-treat analysis | 27 (64) | 22 (58) | 22 (18) | 71 (36) |
| Loss to follow-up | ||||
| Parallel trials (%) | 4 (0–24) | 9 (2–20) | 5 (0–14) | 5 (0–17) |
| Cross-over trials (%) | 3 (0–19) | 0 (0–1) | 0 (0–0) | 0 (0–2) |
| Not reported | 10 (24) | 10 (26) | 37 (31) | 57 (29) |
| Low methodological quality | 15 (36) | 15 (40) | 76 (64) | 106 (53) |
Data are median (interquartile range) or n (%) unless otherwise indicated. IRB, institutional review board.