Summary of GRADE evidence profile of anticoagulation vs antiplatelet therapy alone in patients with cryptogenic stroke
| Outcome Timeframe | Study results and measurements | Absolute effect estimates per 1000 patient-years | Certainty in effect estimates (quality of evidence) | Plain text summary | |
| Antiplatelet | Anticoagulation | ||||
| Ischaemic stroke (standardised to 5 years) | OR: 0.27 (95% CrI 0.03 to 1.21) Direct evidence in NMA from 361 patients in one study Follow-up 5.3 years | 100* per 1000 | 29 per 1000 | Low Due to very serious imprecision‡ | Anticoagulation may decrease ischaemic stroke |
| Difference: 71 fewer (95% CrI 100 fewer† to 17 more) | |||||
| Ischaemic stroke—modelling data from VTE literature (standardised to 5 years) | OR: 0.17 (95% CI 0.08 to 0.36) | 100 per 1000 | 19 per 1000 | Low Due to very serious indirectness§ | Anticoagulation may decrease ischaemic stroke |
| Difference: 81 fewer (95% CI 91 fewer to 62 fewer) | |||||
| Death (standardised to 5 years) | OR: 4.81 (95% CrI 0.31 to 224.43) Direct evidence in NMA from 408 patients in two studies Follow-up 3.2 years | 3 per 1000 | 13 per 1000 | Low Due to very serious imprecision¶ | There may be little or no difference in death |
| Difference: 10 more (95% CrI 3 fewer† to 357 more) | |||||
| Major bleeding (standardised to 5 years) | OR: 1.9 (95% CrI 0.68 to 5.53) Direct evidence in NMA from 408 patients in two studies Follow-up 3.2 years | 14 per 1000 | 26 per 1000 | Moderate Due to serious imprecision** | Anticoagulation probably increases major bleeding |
| Difference: 12 more (95% CrI 5 fewer to 65 more) | |||||
| Major bleeding—modelling data from VTE literature (standardised to 5 years) | OR: 1.77 (95% CI 1.36 to 2.31) | 14 per 1000 | 25 per 1000 | Moderate Due to serious indirectness†† | Anticoagulation probably increases major bleeding |
| Difference: 11 more (95% CI 5 more to 18 more) | |||||
| Transient ischaemic attack (standardised to 5 years) | OR: 0.65 (95% CrI 0.19 to 1.98) Direct evidence in NMA from 361 patients in one study Follow-up 5.3 years | 34 per 1000 | 22 per 1000 | Low Due to very serious imprecision‡‡ | There may be little or no difference in transient ischaemic attack |
| Difference: 12 fewer (95% CrI 34 fewer† to 24 more) | |||||
| Pulmonary embolism—modelling data from VTE literature (standardised to 5 years) | OR: 0.11 (95% CI 0.04 to 0.37) | 5 per 1000 | 1 per 1000 | Moderate Due to serious indirectness§§ | There is probably little or no difference in pulmonary embolism. |
| Difference: 4 fewer (95% CI 5 fewer to three fewer) | |||||
| Systemic embolism (standardised to 5 years) | Not estimable Direct evidence in NMA from 361 patients in one study Follow-up 5.3 years | 0 per 1000 | 0 per 1000 | Moderate Due to serious imprecision¶¶ | There is probably little or no difference in systemic embolism |
The baseline risk for antiplatelet was obtained using calculated absolute effect estimate. This was done to maintain consistency across the tables. The calculated baseline risk (10%) was similar to the baseline risk calculated using the median of studies included (9%).
†The calculated CI using risk difference, because of uncertainty in the point estimates, permits reductions greater than the point estimates in the PFO group. To avoid confusion, we have truncated to present the maximum reduction as equal to the PFO event rate.
‡Imprecision: very serious. Wide CI, includes appreciable harm. Low number of events.
§Indirectness: very serious. In addition to the direct evidence from randomised trials in patients with PFO and a cryptogenic ischaemic stroke, we additionally considered external evidence from randomised trials that assessed the impact of anticoagulation vs antiplatelet therapy for the secondary prevention of venous thromboembolism.
¶Imprecision: very serious. Wide CI, includes both appreciable benefit and harm. Low number of events.
**Imprecision: serious. Wide CIs, Low number of events.
††Indirectness: serious. In addition to the direct evidence from randomised trials in patients with PFO and a cryptogenic ischaemic stroke, we additionally considered external evidence from randomised trials that assessed the impact of anticoagulation vs antiplatelet therapy for the secondary prevention of venous thromboembolism. We did not rate down with two levels because we felt the outcome is less indirect compared with VTE literature than ischaemic stroke.
‡‡Imprecision: very serious. Wide CI, includes both appreciable harm and benefit. Low number of events.
NMA , network meta-analysis; PFO, patent foramen ovale; VTE, venous thromboembolism.