Grade summary of findings for Wang et al 201119
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect (95% CI) | No. of participants (studies) | Quality of the evidence (GRADE) | |
|---|---|---|---|---|---|
| Assumed risk | Corresponding risk | ||||
| Placebo | Hydroxyurea | ||||
| Spleen function Spleen scan uptake | Moderate | Mean difference −11% (−26 to 5) | 144 (1 study) | ⊕⊕⊝⊝ low†‡§ | |
| Renal function Mean DTPA GFR mL/min per 1.73 m2 | The mean renal function in the control groups was mL/min per 1.73 m2 | The mean renal function in the intervention groups was 2 higher (16 lower to 20 higher) | Mean difference 2 mL/min per 1.73 m2 (−16 to 20) | 133 (1 study) | ⊕⊕⊝⊝ low†§ |
| Haematological data(HbF) Percentage | The mean haematological data at exit in the control groups was 17.1% | The mean haematological data at exit in the intervention groups was 22.4% (5.3% higher) | Mean difference 6.7 (4.8 to 8.7) | 158 (1 study) | ⊕⊕⊝⊝ low†§ |
| Pain episodes (vaso-occlusive pain episodes) Number of events | Study population | HR 0.59 (0.42 to 0.83) | 193 (1 study) | ⊕⊕⊝⊝ low† | |
| 773 per 1000 | 583 per 1000 (464 to 708) | ||||
| Moderate | |||||
| Number of transfusions Number of events | Study population | HR 0.55 (0.32 to 0.96) | 193 (1 study) | ⊕⊕⊝⊝ low† | |
| 340 per 1000 | 204 per 1000 (125 to 329) | ||||
| Moderate | |||||
| Acute chest syndrome Number of events | Study population | HR 0.36 (0.15 to 0.87) | 193 (1 study) | ⊕⊕⊝⊝ low†§ | |
| 186 per 1000 | 71 per 1000 (30 to 164) | ||||
| Moderate | |||||
| Dactylitis Number of events | Study population | HR 0.27 (0.15 to 0.5) | 193 (1 study) | ⊕⊕⊝⊝ low†§ | |
| 433 per 1000 | 142 per 1000 (82 to 247) | ||||
| Moderate | |||||
| Rate of hospitalisation Number of events | Study population | HR 0.73 (0.53 to 1) | 193 (1 study) | ⊕⊕⊝⊝ low†§ | |
| 866 per 1000 | 769 per 1000 (655 to 866) | ||||
| Moderate | |||||
| Moderate neutropenia Absolute neutrophil count Follow-up: 24 months | Study population | HR 3.0 (1.7 to 5.1) | 193 (1 study) | ⊕⊕⊝⊝ low†§ | |
| 186 per 1000 Moderate High | 460 per 1000 (295 to 649) | ||||
*The basis for the assumed risk (eg, the median control group risk across studies) is provided in footnotes. The corresponding risk (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).
†Trial downgraded due to indirectness (trial done in USA).
‡Wide CIs.
§Small sample size/small number of events (decreased spleen function events, 19/70 in the HU group and 28/74 in the placebo group).
GRADE Working Group grades of evidence; High quality: Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: 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 quality: We are very uncertain about the estimate.
ANC, absolute neutrophil count; DTPA, diethylenetriaminepentaacetic acid; GFR, glomerular filtration rate; GRADE, Grading of Recommendations Assessment, Development and Evaluation; HbF, fetal haemoglobin; HU, hydroxyurea; RR, rate ratio.