Characteristic | Number | Reports subgroup analysis, n (%) N = 270 | Uses appropriate methods, n (%) N = 185 |
---|---|---|---|
Journal of publication |  | p = 0.01 | p = 0.22 |
 Annals | 37 | 21 (57) | 18 (86) |
 British Medical Journal | 48 | 21 (44) | 12 (57) |
 Journal of the American Medical Association | 76 | 44 (58) | 33 (75) |
 Lancet | 123 | 76 (62) | 52 (68) |
 New England Journal of Medicine | 153 | 108 (71) | 70 (65) |
Year of publication |  | p = 0.27 | p = 0.046 |
 2007 | 119 | 74 (62) | 57 (77) |
 2010 | 144 | 79 (55) | 54 (68) |
 2013–2014 | 174 | 117 (67) | 74 (63) |
Biostatistician as coauthor |  | p = 0.07 | p = 0.38 |
 No biostatistician as coauthor | 183 | 104 (57) | 68 (65) |
 Biostatistician as coauthor | 254 | 166 (65) | 117 (70) |
Medical condition under study |  | p = 0.003 | p < 0.001 |
 Cardiovascular | 101 | 73 (72) | 63 (86) |
 Infectious disease | 82 | 52 (63) | 25 (48) |
 Cancer | 59 | 45 (76) | 24 (53) |
 Psychiatry/neurology | 40 | 20 (50) | 11 (55) |
 Autoimmune, including diabetes | 37 | 22 (59) | 15 (68) |
 Pulmonary/critical care | 29 | 14 (48) | 11 (79) |
 Obstetrics/gynecological | 21 | 10 (48) | 8 (80) |
 Other chronic disease | 41 | 24 (59) | 19 (79) |
 Other, uncategorized | 27 | 10 (37) | 9 (90) |
First author’s region |  | p = 0.14 | p = 0.19 |
 North America | 185 | 123 (66) | 84 (68) |
 Europe | 188 | 113 (60) | 82 (73) |
 Other | 64 | 34 (53) | 19 (56) |
Funding |  | p < 0.001 | p = 0.005 |
 Industry funding | 188 | 141 (75) | 86 (61) |
 No industry funding | 249 | 129 (52) | 99 (77) |
Significance of the primary outcomea |  | p = 0.013 | p = 0.003 |
 Not significant | 153 | 106 (69) | 85 (80) |
 Significant | 277 | 158 (57) | 100 (63) |
Study design |  | p = 0.002 | p = 0.53) |
 Parallel | 425 | 268 (63) | 18 (69) |
 Crossover | 12 | 2 (17) | 1 (50) |
Sample size |  | p < 0.001 | p = 0.01 |
 Quintile 1 (median = 69) | 88 | 29 (33) | 13 (45) |
 Quintile 2 (median = 234) | 87 | 44 (51) | 30 (68) |
 Quintile 3 (median = 507) | 88 | 58 (66) | 39 (67) |
 Quintile 4 (median = 1080) | 87 | 65 (75) | 48 (74) |
 Quintile 5 (median = 5455) | 87 | 74 (85) | 55 (74) |