Summary of findings 5. Hydroxyurea compared to RBC transfusions for prevention of SCI in people with SCD who have not had a stroke (primary prevention).
| Hydroxyurea compared to RBC transfusions for prevention of SCI in people with SCD who have not had a stroke (primary prevention) | ||||||
| Patient or population: prevention of SCI in people with SCD who have not had a stroke (primary prevention) Setting: outpatients Intervention: hydroxyurea Comparison: RBC transfusions | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Risk with RBC transfusions | Risk with hydroxyurea | |||||
| Proportion of participants developing new or progressive SCI lesions | No SCIs occurred in either trial arm | ‐ | 121 (1 RCT) | ⊕⊝⊝⊝ VERY LOW 1 2 3 | ||
| All‐cause mortality | No deaths occurred in either trial arm | ‐ | (1 RCT) | ⊕⊝⊝⊝ VERY LOW 1 2 3 | ||
| SCD‐related SAEs ‐ ACS | Trial population | RR 2.03 (0.39 to 10.69) | 121 (1 RCT) | ⊕⊝⊝⊝ VERY LOW 1 3 4 | ||
| 33 per 1000 | 67 per 1000 (13 to 350) | |||||
| SCD‐related SAEs ‐ pain crisis | Trial population | RR 5.08 (0.61 to 42.23) | 121 (1 RCT) | ⊕⊝⊝⊝ VERY LOW 1 3 4 | ||
| 16 per 1000 | 83 per 1000 (10 to 692) | |||||
| Clinical stroke | No strokes occurred in either trial arm | ‐ | 121 (1 RCT) | ⊕⊝⊝⊝ VERY LOW 1 2 3 | ||
| Cognitive function ‐ not reported | ‐ | ‐ | ‐ | ‐ | ‐ | |
| Quality of life ‐ not reported | ‐ | ‐ | ‐ | ‐ | ‐ | |
| *The risk in the intervention group (and its 95% CI) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). ACS: acute chest syndrome; CI: confidence interval; RBC: red blood cells; RCT: randomised controlled trial; RR: risk ratio; SAEs: serious adverse events; SCD: sickle cell disease; SCI: silent cerebral infarcts | ||||||
| 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 indirectness. Only children with HbSS or HbSβº thalassaemia included. If this review was only considering the quality of evidence for children with HbSS the quality of evidence would not have been downgraded for indirectness.
2 We downgraded the quality of evidence by 1 due to imprecision. Rare events. No SCIs or strokes occurred
3 We downgraded the quality of evidence by 1 due to risk of bias. Trial was stopped early some outcomes assessed without blinding
4 We downgraded the quality of evidence by 1 due to imprecision. Estimate has wide confidence intervals that include both clinically relevant benefits and harms