Twenty RCTs (n=65,261) were included: four assessed atorvastatin (n=15,907); three assessed fluvastatin (n=3,463); 11 assessed pravastatin (n=38,367); and two assessed lovastatin (n=7,524). No studies that assessed rosuvastatin or simvastatin were found. Study size ranged from 164 to 10,355 participants. All studies reported blinding of participants and assessors. Intention to treat (ITT) was reported in 19 studies. Allocation concealment was reported in 10 studies. Mean follow up ranged from one year to 5.3 years.
The authors stated that tests showed no indication of publication bias (data not reported).
Use of statins reduced all cause mortality (RR 0.93, 95% CI: 0.87 to 0.99, p=0.03, I2=5%; 19 trials), cardiovascular disease deaths (RR 0.89, 95% CI: 0.81 to 0.98, p=0.02, I2=0%; 17 trials), death from myocardial infarction (RR 0.46, 95% CI: 0.26 to 0.79, p=0.005, I2=0%; nine trials), major cardiovascular events (RR 0.85, 95% CI: 0.77 to 0.95, p=0.004, I2=61%; 17 trials) and myocardial infarction (RR 0.77, 95% CI: 0.63 to 0.95, p=0.001, I2=59%; 17 trials).
When heterogeneity was investigated, studies that reported allocation concealment appeared to show increases in events for mortality, cardiovascular death, major cardiovascular events and myocardial infarction with statin treatment
Results for other cardiovascular outcomes were reported in the paper.
Statins had no effect on cancer incidence (RR 1.02, 95% CI: 0.94 to 1.11, p=0.59, I2=0%; 10 trials) or on rhabdomyolysis (RR 0.97, 95% CI: 0.25 to 3.83, p=0.96, I2=0%; 9 trials with 39,383 participants and only four cases of rhabdomyolysis).
Results from the mixed treatment comparison modelling estimated that atorvastatin was the most effective statin for reducing all cause mortality (probability of 48%) and lovastatin for reducing cardiovascular disease mortality (probability of 60%).