Table 1.
GRADE evaluation of interventions for primary prevention of CVD: treating dyslipidaemia
| Important outcomes | CVD events, mortality, adverse effects | ||||||||
| Number of studies (participants) | Outcome | Comparison | Type of evidence | Quality | Consistency | Directness | Effect size | GRADE | Comment |
| What are the effects of pharmacological cholesterol-lowering interventions in people at low risk (<0.6% annual CHD risk)? | |||||||||
| 1 (7832) | CVD events | Statin plus cholesterol-lowering diet v cholesterol-lowering diet alone (low risk) | 4 | 0 | 0 | –1 | 0 | Moderate | Directness point deducted for use of an active co-intervention (cholesterol-lowering diet) |
| What are the effects of pharmacological cholesterol-lowering interventions in people at medium risk (0.6–1.4% annual CHD risk)? | |||||||||
| 1 (4081) | Mortality | Fibrates v placebo (medium risk) | 4 | –1 | 0 | 0 | 0 | Moderate | Quality point deducted for incomplete reporting of results |
| 1 (4081) | CVD events | Fibrates v placebo (medium risk) | 4 | 0 | 0 | 0 | 0 | High | |
| 1 (3806) | CVD events | Resins v placebo (medium risk) | 4 | 0 | 0 | –2 | 0 | Low | Directness points deducted for uncertainty of benefit of treatment and narrow population (only men) |
| 2 (16,960) | Mortality | Statins v placebo/usual care (medium risk) | 4 | 0 | 0 | –2 | 0 | Low | Directness points deducted for one RCT not being powered to detect a difference between groups, uncertainty of benefit in one RCT (due to high rate of conversion from placebo to statin), and inclusion of some people with history of CVD in one RCT |
| 2 (16,960) | CVD events | Statins v placebo/usual care (medium risk) | 4 | 0 | 0 | –2 | 0 | Low | Directness points deducted for uncertainty of benefit in one RCT (due to high rate of conversion from placebo to statin) and inclusion of some people with history of CVD in one RCT |
| What are the effects of pharmacological cholesterol-lowering interventions in people at high risk (1.5% or more annual CHD risk)? | |||||||||
| 1 (6595) | Mortality | Statins v placebo (in people at high risk) | 4 | 0 | 0 | –1 | 0 | Moderate | Directness point deducted for narrow population (only men) |
| 3 (13,263) | CVD events | Statins v placebo (in people at high risk) | 4 | –1 | 0 | –1 | 0 | Low | Quality point deducted for methodological limitations (subgroup analysis in one RCT and incomplete reporting of results in one RCT). Directness point deducted for narrow populations (only men in one RCT, and only older people in one RCT) |
| What are the effects of reduced- or modified-fat diet in people at low, medium, or high risk of CHD? | |||||||||
| At least 27 RCTs (at least 48,939) | Mortality | Reduced- or modified-fat diet v no dietary modification | 4 | 0 | 0 | 0 | 0 | High | |
| 28 RCTs (at least 48, 835) | CVD events | Reduced- or modified-fat diet v no dietary modification | 4 | 0 | –1 | 0 | 0 | Moderate | Consistency point deducted for conflicting results |
Type of evidence: 4 = RCT; 2 = Observational; 1 = Non-analytical/expert opinion. Consistency: similarity of results across studies Directness: generalisability of population or outcomes Effect size: based on relative risk or odds ratio