| Characteristic | No. (%) of RCD studies* | p value | ||
|---|---|---|---|---|
| All studies n = 337 | Studies with existing RCTs† n = 231 | Studies without existing RCTs n = 106 | ||
| Publication year, median (IQR) | 2008 (2006-2009) | 2008 (2007-2009) | 2008 (2005-2009) | 0.4 |
| Type of condition/disease/specialty | 0.06 | |||
| Chronic kidney disease | 10 (3.0) | 4 (1.7) | 6 (5.7) | |
| Cardiovascular disease | 213 (63.2) | 155 (67.1) | 58 (54.7) | |
| Cancer | 39 (11.6) | 26 (11.3) | 13 (12.3) | |
| Diabetes mellitus | 8 (2.4) | 6 (2.6) | 2 (1.9) | |
| Pediatrics | 3 (0.9) | 3 (1.3) | 0 | |
| Pregnancy | 1 (0.3) | 1 (0.4) | 0 | |
| Psychiatry | 11 (3.3) | 8 (3.5) | 3 (2.8) | |
| Pulmonology | 10 (3.0) | 6 (2.6) | 4 (3.8) | |
| Surgery | 10 (3.0) | 4 (1.7) | 6 (5.7) | |
| Transplantation | 15 (4.5) | 6 (2.6) | 9 (8.5) | |
| Other | 17 (5.0) | 12 (5.2) | 5 (4.7) | |
| Type of treatment | < 0.001 | |||
| Coronary revascularization | 94 (27.9) | 74 (32.0) | 20 (18.9) | |
| Devices | 9 (2.7) | 3 (1.3) | 6 (5.7) | |
| Drugs | 162 (48.1) | 124 (53.7) | 38 (35.8) | |
| Radiation | 10 (3.0) | 5 (2.2) | 5 (4.7) | |
| Surgery‡ | 35 (10.4) | 15 (6.5) | 20 (18.9) | |
| Different types§ | 8 (2.4) | 3 (1.3) | 5 (4.7) | |
| Other | 19 (5.6) | 7 (3.0) | 12 (11.3) | |
| Type of comparator | 0.2 | |||
| Active intervention | 175 (51.9) | 125 (54.1) | 50 (47.2) | |
| Usual care | 162 (48.1) | 106 (45.9) | 56 (52.8) | |
| Type of routine data | 0.6 | |||
| Registry data | 217 (64.4) | 147 (63.6) | 70 (66.0) | |
| Administrative data | 46 (13.6) | 34 (14.7) | 12 (11.3) | |
| EMR/EHR | 7 (2.1) | 6 (2.6) | 1 (0.9) | |
| Other | 67 (19.9) | 44 (19.0) | 23 (21.7) | |
Note: EHR = electronic health record, EMR = electronic medical record, IQR = interquartile range, RCT = randomized controlled trial.
*Unless stated otherwise.
†Studies in which RCTs (or meta-analyses or systematic reviews of RCTs) on the same research question were mentioned or cited, or cases where at least 1 previous RCT was identified in the literature searches.
‡Excludes coronary artery bypass graft surgery, which is included under coronary revascularization.
§Comparison of different types of interventions (e.g., drug therapy v. radiation).