Summary of findings 1. Heparin versus placebo for non‐ST elevation acute coronary syndromes.
| Heparin versus placebo for non‐ST elevation acute coronary syndromes | ||||||
| Patient or population: patients with non‐ST elevation acute coronary syndromes Settings: Inpatients Intervention: Heparin Comparison: Placebo or untreated control | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect (95% CI) | No of Participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Assumed risk | Corresponding risk | |||||
| ASA | Heparin + ASA | |||||
| All‐cause mortality Follow‐up: 5‐150 days | Study population | RR 0.84 (0.36 to 1.98) | 2426 (6 studies) | ⊕⊕⊝⊝ low1,2,3 | Low due to study limitations and imprecision | |
| 9 per 1000 | 8 per 1000 (3 to 18) | |||||
| Moderate | ||||||
| Incidence of myocardial infarction Follow‐up: 5‐150 days | Study population | RR 0.4 (0.25 to 0.63) | 2426 (6 studies) | ⊕⊕⊝⊝ low4 | Low quality because of very serious study limitations | |
| 48 per 1000 | 19 per 1000 (12 to 30) | |||||
| Moderate | ||||||
| 58 per 1000 | 23 per 1000 (15 to 37) | |||||
| Recurrent angina Follow‐up: 5‐150 days | Study population | RR 0.81 (0.6 to 1.09) | 2426 (6 studies) | ⊕⊝⊝⊝ very low4,6 | Very low due to study limitations and inconsistency | |
| 166 per 1000 | 134 per 1000 (99 to 181) | |||||
| Moderate | ||||||
| 361 per 1000 | 292 per 1000 (217 to 393) | |||||
| Incidence of revascularization procedures Follow‐up: 5‐150 days | Study population | RR 0.93 (0.76 to 1.15) | 2520 (6 studies) | ⊕⊕⊝⊝ low4 | Low quality because of very serious study limitations | |
| 96 per 1000 | 90 per 1000 (73 to 111) | |||||
| Moderate | ||||||
| 135 per 1000 | 126 per 1000 (103 to 155) | |||||
| Major hemorrhage Follow‐up: 2‐150 days | Study population | RR 2.05 (0.91 to 4.6) | 3118 (8 studies) | ⊕⊕⊝⊝ low5 | Low quality because of very serious study limitations | |
| 5 per 1000 | 9 per 1000 (4 to 21) | |||||
| Moderate | ||||||
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: Confidence interval; RR: Risk ratio; | ||||||
| GRADE Working Group grades of evidence High quality: Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: We are very uncertain about the estimate. | ||||||
1 Allocation concealment was uncertain in the majority of the evaluated trials. Lack of blinding of participants and outcome assessors in two trials, blinding of outcome assessors is uncertain in three trials. Final decision: rate down by one level (lack of blinding not considered a serious study limitation for the outcome of all‐cause mortality). Two trials stopped early for benefit; stopping early as a source of bias is questionable. Final decision was not to rate down for stopping early for benefit. 2 Wide confidence intervals and few events. We decided to rate down for imprecision because confidence intervals fails to exclude important benefit or important harm. 3 Funnel plot could be interpreted as suggesting of publication bias. However, the number of studies is insufficient to meet rigorous criteria for creating a funnel plot. Final decision: publication bias is speculative (not rate down). 4 Allocation concealment was uncertain in the majority of the evaluated trials. Lack of blinding of participants in four trials, lack of blinding of outcome assessors in two trials, blinding of outcome assessors is uncertain in three trials. Final decision: rate down by two levels.Two trials stopped early for benefit; stopping early as a source of bias is questionable. Final decision was not to rate down for stopping early for benefit. 5 Allocation concealment was uncertain in the majority of the evaluated trials. Lack of blinding of participants in four trials, lack of blinding of outcome assessors in two trials, blinding of outcome assessors is uncertain in five trials. Final decision: rate down by two levels.Two trials stopped early for benefit; stopping early as a source of bias is questionable. Final decision was not to rate down for stopping early for benefit.
6 Results were inconsistent across studies as evidenced by I² = 65%