Summary of findings 1. Aspirin (ASA) compared to vitamin K antagonist (VKA) for ambulatory patients with multiple myeloma receiving immunomodulatory agents: 6 months follow‐up.
| Aspirin (ASA) compared to vitamin K antagonist (VKA) for ambulatory patients with multiple myeloma receiving immunomodulatoryagents: 6 months follow‐up | |||||
| Patient or population: ambulatory patients with multiple myeloma receiving immunomodulatory agents: 6 months follow‐up Setting: outpatient Intervention: aspirin prophylaxis Control: vitamin K antagonist prophylaxis | |||||
| Outcomes | № of participants (studies) | Certainty of the evidence (GRADE) | Relative effect (95% CI) | Anticipated absolute effects* (95% CI) | |
| Risk with VKA | Risk difference with ASA | ||||
| All‐cause mortality follow‐up: 6 months | 440 (1 RCT) | ⊕⊝⊝⊝ VERY LOW 1 2 | RR 3.00 (0.12 to 73.24) | Low | |
| 1 per 1000 3 | 2 more per 1000 (1 fewer to 72 more) | ||||
| Symptomatic deep vein thrombosis follow‐up: 6 months | 440 (1 RCT) | ⊕⊝⊝⊝ VERY LOW 2 4 | RR 0.57 (0.24 to 1.33) | Study population | |
| 64 per 1000 | 27 fewer per 1000 (48 fewer to 21 more) | ||||
| Pulmonary embolism follow‐up: 6 months | 440 (1 RCT) | ⊕⊝⊝⊝ VERY LOW 2 5 | RR 1.00 (0.25 to 3.95) | Study population | |
| 18 per 1000 | 0 fewer per 1000 (14 fewer to 54 more) | ||||
| Major bleeding follow‐up: 6 months | 440 (1 RCT) | ⊕⊝⊝⊝ VERY LOW 2 6 | RR 7.00 (0.36 to 134.72) | Low | |
| 1 per 1000 3 | 6 more per 1000 (1 fewer to 134 more) | ||||
| Minor bleeding follow‐up: 6 months | 440 (1 RCT) | ⊕⊝⊝⊝ VERY LOW 2 7 | RR 6.00 (0.73 to 49.43) | Study population | |
| 5 per 1000 | 23 more per 1000 (1 fewer to 220 more) | ||||
| *The risk in the intervention group (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; RCT: randomised controlled trial; RR: risk ratio | |||||
| GRADE Working Group grades of evidence High certainty: We are very confident that the true effect lies close to that of the estimate of the effect. Moderate certainty: We are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. Low certainty: Our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect. Very low certainty: We have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect. | |||||
1Downgraded by two levels due to concerns about imprecision; 95% CI is consistent with the possibility of no effect (1 per 1000 absolute reduction) and the possibility of important harm (72 per 1000 absolute increase), including one event in total. Given the observed baseline risk of 0%, we used 0.1% to generate an absolute effect and a confidence interval. 2Downgraded by one level due to serious risk of bias. Lack of blinding of participants and personnel and selective reporting (all outcomes listed in the methods section were reported on in the results except for secondary endpoint related to any toxicity that required interruption of study prophylaxis). 3There were zero events in the control arm. 4Downgraded by two levels due to concerns about imprecision; 95% CI is consistent with the possibility of important benefit (48 per 1000 absolute reduction) and the possibility of important harm (21 per 1000 absolute increase), including 22 events in total. 5Downgraded by two levels due to concerns about imprecision; 95% CI is consistent with the possibility of important benefit (14 per 1000 absolute reduction) and the possibility of important harm (54 per 1000 absolute increase), including eight events in total. 6Downgraded by two levels due to concerns about imprecision; 95% CI is consistent with the possibility of no effect (1 per 1000 absolute reduction) and the possibility of important harm (134 per 1000 absolute increase), including three events in total. Given the observed baseline risk of 0%, we used 0.1% to generate an absolute effect and a confidence interval. 7Downgraded by two levels due to concerns about imprecision; 95% CI is consistent with the possibility of no effect (1 per 1000 absolute reduction) and the possibility of important harm (220 per 1000 absolute increase), including seven events in total.