Summary of findings 4. Lipid‐lowering agent compared to placebo or no treatment for asymptomatic carotid stenosis.
| Lipid‐lowering agent compared to placeboa or no treatment for asymptomatic carotid stenosis | |||||
| Patient or population: asymptomatic carotid stenosis Setting: outpatients Intervention: lipid‐lowering agent Comparison: placebo or no treatment | |||||
| Outcomes (measurement/time point) | № of participants (studies) | Certainty of the evidence (GRADE) | Relative effect (95% CI) | Anticipated absolute effects* (95% CI) | |
| Risk with placebo or no treatment | Risk difference with lipid‐lowering agent | ||||
| Neurological impairment | The included studies did not measure this outcome. | ||||
| Ipsilateral major or disabling stroke (only reported for two studies: one used CT scan, MRI and hospital records/every 6 weeksb; the other used physical examination/at beginning and 10 days after the endc) Follow‐up: 3.1 years |
2235 (5 RCTs)d | ⊕⊕⊝⊝ Lowe | RR 0.36 (0.09 to 1.53) | Study population | |
| 18 per 1000 | 11 fewer per 1000 (16 fewer to 10 more) | ||||
| Stroke‐related mortality (only reported for one study: CT scan, MRI and hospital records/every 6 weeksb) Follow‐up: 4 years |
1366 (2 RCTs)f | ⊕⊕⊝⊝ Lowe | RR 0.25 (0.03 to 2.29) | Study population | |
| 4 per 1000 | 3 fewer per 1000 (4 fewer to 6 more) | ||||
| Major bleeding | The included studies did not measure this outcome. | ||||
| Progression of carotid stenosis | The included studies did not measure this outcome. | ||||
| Adverse events (only reported for two studies: one study used CT scan, MRI and hospital records/every 6 weeksb; the other used physical examination/at beginning and 10 days after the endc) Follow‐up: 3.3 years |
3726 (7 RCTs)g | ⊕⊕⊝⊝ Lowe | RR 0.76 (0.53 to 1.10) | Study population | |
| 86 per 1000 | 21 fewer per 1000 (41 fewer to 9 more) | ||||
| Quality of life | The included studies did not measure this outcome. | ||||
| *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). CI: confidence interval; CT scan: computerised tomography scan; MRI: magnetic resonance imaging; №: number; 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. | |||||
aNine studies included in this comparison bFurberg 1994 cZheng 2022 dLovastatin, pravastatin, rosuvastatin, and atorvastatin eDowngraded two levels due to imprecision: few events, one study, and 95% CI consistent with possible benefit and possible harm fLovastatin and pravastatin gFluvastatin, rosuvastatin, lovastatin, pravastatin, and probucol