Statin therapy versus control
Statin therapy significantly reduces the incidence of major vascular events and vascular mortality in a wide range of people
Results of observational studies in different populations indicated a continuous positive relationship between coronary heart disease risk and blood cholesterol concentrations that extends well below the range seen in many developed populations, without any definite threshold below which a lower cholesterol concentration was not associated with lower risk. However, there remained substantial uncertainty about the effects on major morbidity of lowering blood cholesterol by drugs such as statins. In addition, the effect of statins on vascular mortality were not able to be reliably addressed among the early statin trials since no single trial would have had sufficient statistical power to reliably assess this outcome. The CTT Collaboration conducted meta-analyses of combined data from large randomized controlled trials of statin therapy to address these uncertainties.
Individual participant data meta-analyses from randomized trials of statin therapy were performed. Initial analyses included 14 trials of statin versus control (involving approximately 90,000 individuals) with subsequent analyses including a total of >20 trials of statin versus control (involving approximately 135,000 individuals). Median follow-up was approximately 5 years.
- Reduction of LDL cholesterol using statin therapy reduces the risk of major vascular events by about one fifth for each 1 mmol/L reduction in LDL cholesterol, largely irrespective of baseline cholesterol concentration or other presenting characteristics.
Reduction of LDL cholesterol using statin therapy reduces all-cause mortality by about one tenth for each 1 mmol/L reduction in LDL cholesterol, principally reflecting a significant reduction in vascular mortality.
The reduction in vascular mortality is chiefly attributable to about a one fifth reduction in deaths due to coronary disease and about a one tenth reduction in deaths due to other cardiac causes for each 1 mmol/L reduction in LDL cholesterol.
Benefits were significant within the first year, but greater in subsequent years.
No significant effects of statins on deaths due to stroke or other vascular causes.
- The magnitude of the absolute benefit of a particular statin regimen in an individual over a specified period of time is determined by: (i) their estimated risk of major vascular events over that time; and (ii) the absolute reduction in LDL cholesterol produced by that statin regimen.