Summary of findings 1. Long‐term red cell transfusion versus no transfusion in people who are at risk of a primary stroke who have not had previous long‐term red cell transfusions.
| Primary prevention | ||||||
| Patient or population: individuals with sickle cell disease who are at risk of a primary stroke who have not had previous long‐term red cell transfusions Setting: outpatients Intervention: long‐term red cell transfusion Comparison: standard care | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (trials) | Quality of the evidence (GRADE) | Comments | |
| Risk with standard care | Risk with Blood transfusion | |||||
| Clinical stroke follow‐up: mean 24 months | Trial population | RR 0.12 (0.03 to 0.49) | 326 (2 RCTs) | ⊕⊕⊕⊝ Moderate 3 | ||
| 110 per 1000 | 13 per 1000 (3 to 54) |
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| All‐cause mortality | No deaths occurred in either trial arm | ‐ | 326 (2 RCTs) | ⊕⊝⊝⊝ Very low 1 2 3 | ||
| Adverse events associated with transfusion assessed with: alloimmunisation | Moderatea | RR 3.16 (0.18 to 57.17) | 121 (1 RCT) | ⊕⊝⊝⊝ Very low 2 3 4 | ||
| 10 per 1000 | 32 per 1000 (2 to 572) |
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| TIA | Trial population | Peto OR 0.13 (0.01 to 2.11) |
323 (2 RCTs) |
⊕⊝⊝⊝ Very low 3 4 | ||
| 21 per 1000 | 5 per 1000 (0 to 43) |
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| Serious adverse events as a result of sickle cell‐related complications assessed with: ACS | Trial population | RR 0.24 (0.12 to 0.48) | 326 (2 RCTs) | ⊕⊕⊝⊝ Low 2 3 | ||
| 232 per 1,000 | 56 per 1000 (28 to 111) |
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| Moderate | ||||||
| 230 per 1000 | 55 per 1000 (28 to 110) |
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| Measures of neurological impairment assessed with: WASI IQ score | Least square mean 1.7 (SE 95% CI ‐1.1 to 4.4) |
‐ | 166 (1 RCT) |
⊕⊕⊝⊝ Low 2 3 | Author reported data from SIT 2014 | |
| Quality of life assessed with: Child Health Questionnaire Parent Form 50 |
Difference estimate ‐0.54 (‐0.92 to ‐0.17) | ‐ | 196 (1 RCT) |
⊕⊕⊝⊝ Low 2 3 | Author reported data from SIT 2014 | |
| *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). Abbreviations: ACS: acute chest syndrome; CI: confidence interval; RCT: randomised controlled trial; RR: risk ratio; OR: odds ratio; TIA: transient ischaemic attack. | ||||||
| GRADE Working Group grades of evidence High quality: we are very confident that the true effect lies close to that of the estimate of the effect Moderate quality: 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 quality: our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect Very low quality: we have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect | ||||||
1 We downgraded the quality of evidence by 1 due to imprecision. Rare event. No deaths occurred.
2 We downgraded the quality of the evidence by 1 due to risk of bias. Unblinded trial and cross‐overs, and imbalance between loss to follow‐up between trial arms
3 We downgraded the quality of the evidence by 1 due to indirectness. Only children with HbSS or HbSβº thalassaemia included in trials
4 We downgraded the quality of evidence by 2 due to imprecision. The estimate has very wide CIs
a Based on Chou 2013