Table 1 Study characteristics and risk of bias of the 127 included randomized controlled trials
Study characteristics | |
Journal, n (%) | |
New England Journal of Medicine | 65 (51) |
Lancet | 23 (18) |
Journal of the American Medical Association | 20 (16) |
British Medical Journal | 5 (4) |
Annals of Internal Medicine | 1 (1) |
Circulation | 13 (10) |
Setting, n | |
Community | 74 (58) |
Hospital | 53 (42) |
Primary or secondary prevention, n | |
Primary | 19 (15) |
Secondary | 108 (85) |
Experimental interventional, n | |
Medication | 65 (51) |
Surgery | 32 (25) |
Models of care | 11 (9) |
Vitamin/supplement | 9 (7) |
Lifestyle | 4 (3) |
Diagnostics/other* | 6 (5) |
Patient characteristics | |
Median age (interquartile range), years | 63.8 (61.5–66.5) |
Percent males (interquartile range) | 72.0 (60.4–78.0) |
Study size and duration | |
Median study size (interquartile range) | 3020 (1319–8521) |
Median study duration (interquartile range), months | 24.0 (8.3–45.3) |
Primary outcome included (median 3, range 1–10), n (%) | |
Myocardial infarction | 101 (80) |
Stroke | 83 (65) |
Cardiovascular death | 64 (50) |
Overall death | 51 (40) |
Revascularization | 31 (25) |
Heart failure | 22 (17) |
Othera | 37 (29) |
Risk of bias, n (%) | |
Planned trial duration | |
Completed as planned | 95 (75) |
Extended | 4 (3) |
Stopped for benefit | 8 (6) |
Stopped for harm | 10 (8) |
Stopped for futility | 9 (7) |
Stopped for financial reasons | 1 (1) |
Allocation concealment | |
Yes | 98 (77) |
Unclear/no | 29 (23) |
Blinding | |
Double | 65 (51) |
Single | 13 (10) |
None | 49 (39) |
Analysis | |
Intention to treat | 119 (94) |
Modified intention to treat | 7 (6) |
Per protocol | 1 (1) |
Sample size estimation | |
Estimation attained | 83 (65) |
Estimation missed | 38 (30) |
No estimation given | 6 (5) |
Withdrawal | |
Number provided | 115 (91) |
Median (interquartile range) | 2.3 (0.5–7.0) |
Funding | |
Industry | 52 (41) |
Mixed | 46 (36) |
Public | 28 (22) |
Not described | 1 (1) |