Summary of findings 4. Low‐molecular‐weight heparin versus active control (2).
| LMWH compared with aspirin for primary thromboprophylaxis in ambulatory cancer patients receiving chemotherapy | |||||||
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Patient or population: ambulatory cancer patients receiving chemotherapy Settings: outpatient clinics Intervention: LMWH Comparison: aspirin | |||||||
| Outcomes | Relative effect (95% CI) | Illustrative comparative risks* (95% CI) | Differenceb (95% CI) | No of participants (studies) | Certainty of the evidence (GRADE) | What it means | |
| Assumed riska | Corresponding risk | ||||||
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With aspirin Number of events per 1000 participants |
With LMWH
(any dosage) Number of events per 1000 participants |
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Symptomatic VTE Follow‐up: median 18.5 months |
RR 0.51 (0.22 to 1.17) | Intermediate‐risk populationc | 19 per 1000 fewer events (30 fewer to 7 more) | 781 (2) | ⊕⊕⊕⊝ Moderated | LMWH probably decreases the incidence of symptomatic VTE when compared with aspirin in multiple myeloma. | |
| 39 per 1000 | 20 per 1000 (9 to 45) | ||||||
|
Major bleeding Follow‐up: median 18.5 months |
RR 0.14 (0.01 to 2.76) | Intermediate‐risk populationc | 6 per 1000 fewer events (7 fewer to 12 more) | 781 (2) | ⊕⊕⊝⊝ Lowe | LMWH may reduce the incidence of major bleeding when compared with aspirin in multiple myeloma. | |
| 7 per 1000 | 1 per 1000 (0 to 19) | ||||||
|
Symptomatic PE Follow‐up: median 18.5 months |
RR 0.13 (0.02 to 1.03) | Intermediate‐risk populationc | 15 per 1000 fewer events (17 fewer to 1 more) | 781 (2) | ⊕⊕⊕⊝ Moderated | LMWH probably reduces the incidence of symptomatic PE when compared with aspirin in multiple myeloma. | |
| 18 per 1000 | 2 per 1000 (0 to 18) | ||||||
|
Symptomatic DVT Follow‐up: median 18.5 months |
RR 0.81 (0.32 to 2.04) | Intermediate‐risk populationc | 5 per 1000 fewer events (16 fewer to 25 more) | 781 (2) | ⊕⊕⊕⊝ Moderated | LMWH probably reduces the incidence of symptomatic DVT when compared with aspirin in multiple myeloma. | |
| 24 per 1000 | 19 per 1000 (8 to 49) | ||||||
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Any VTE Follow‐up: NA |
NAf | Intermediate‐risk populationc | NA | NA | NA | We do not know how LMWH affects any VTE when compared with aspirin in multiple myeloma. | |
| NA | NA | ||||||
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1‐year overall mortality Follow‐up: NA |
NAf | Intermediate‐risk populationc | NA | NA | NA | We do not know how LMWH affects 1‐year overall mortality when compared with aspirin in multiple myeloma. | |
| NA | NA | ||||||
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Clinically relevant bleeding Follow‐up: NA |
NAf | Intermediate‐risk populationc | NA | NA | NA | We do not know how LMWH affects clinically relevant bleeding when compared with aspirin in multiple myeloma. | |
| NA | NA | ||||||
| *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; DVT: deep vein thrombosis; LMWH: low‐molecular‐weight heparin; NA: not applicable; PE: pulmonary embolism; RR: risk ratio; VTE: venous thromboembolism. | |||||||
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GRADE Working Group grades of evidence High certainty: further research is very unlikely to change our confidence in the estimate of effect. Moderate certainty: further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low certainty: 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 certainty: we are very uncertain about the estimate. | |||||||
aThe assumed risk was calculated from the medium observed control group risk across the studies. bDifference calculated as the absolute risk difference between the assumed risk and corresponding risk, expressed per 1000. cIntermediate‐risk population refers to the median observed risk to experience symptomatic VTE in the trials contributing to the analyses (39 per 1000). Rates between 2% and 7% are considered intermediate risk (Khorana 2008). dDowngraded one level because of imprecision. eDowngraded two levels because of imprecision. fNo trials contributed to this outcome.