A Cochrane review included 22 studies with a total of 3 465 subjects; 17 studies (n=3 282) compared statin with placebo or no treatment, and 5 studies (n=183) compared two different statin regimens.
Statins seemed to reduce statistically non-significantly major cardiovascular events, cardiovascular mortality (table ), and fatal or non-fatal myocardial infarction (RR 0.70, 95% CI 0.48 to 1.01; 1 study, n=2 102).
| Outcome | Relative effect (95% CI) | Assumed risk (placebo or no treatment) | Corresponding risk (statin) | Participants (studies) |
|---|---|---|---|---|
| Major cardiovascular events | RR 0.84 (0.66 to 1.06) | 20 per 1000 | 17 per 1000 (13 to 21) | 2 102 (1) |
| All-cause mortality | RR 1.08 (0.63 to 1.83) | 20 per 1000 | 22 per 1000 (12 to 37) | 2 760 (6) |
| Cardiovascular mortality | RR 0.68 (0.45 to 1.01) | 5 per 1000 | 3 per 1000 (2 to 5) | 2 322 (4) |
Statins had uncertain effects on all-cause mortality (table ), fatal or non-fatal stroke (RR 1.18, 95% CI 0.85 to 1.63; 1 study, n=2 102), creatine kinase elevation (RR 0.86, 95% CI 0.39 to 1.89; 3 studies, n=2 233); liver enzyme elevation (RR 0.62, 95% CI 0.33 to 1.19; 4 studies, n=608), withdrawal due to adverse events (RR 0.89, 95% CI 0.74 to 1.06; 9 studies, n=2 810), and cancer (RR 0.94, 95% CI 0.82 to 1.07; 1 study, n=2 094).
Statins significantly reduced serum total cholesterol (MD -42.43 mg/dL (=1.1 mmol/L), 95% CI -51.22 to -33.65; 12 studies, n=3 070); low-density lipoprotein cholesterol (MD -43.19 mg/dL, 95% CI -52.59 to -33.78; 11 studies, n=3 004); serum triglycerides (MD -27.28 mg/dL, 95% CI -34.29 to -20.27; 11 studies, n=3 012); and lowered high-density lipoprotein cholesterol (MD -5.69 mg/dL, 95% CI -10.35 to -1.03; 11 studies, n=3 005). There was marked heterogeneity in the analyses for total cholesterol, LDL cholesterol and HDL cholesterol levels.
Statins had uncertain effects on kidney function: ESKD (RR 1.14, 95% CI 0.94 to 1.37; 6 studies, n=2 740); proteinuria (MD -0.04 g/24 h, 95% CI -0.17 to 0.25; 2 studies, n=136); acute allograft rejection (RR 0.88, 95% CI 0.61 to 1.28; 4 studies, n=582); and GFR (MD -1.00 mL/min, 95% CI -9.96 to 7.96; 1 study, n=62).
Data directly comparing differing statin regimens could not be meta-analysed.
Comment: The quality of evidence is downgraded by study quality (inadequate or unclear allocation concealment and lack of blinding).