title: [Lowering LDL-cholesterol: the lower the better?]
abstract: There is still a debate about the optimal LDL level to achieve with pharmacological treatment. Some support the 'the lower, the better' approach, others support 'a level less than 2.5 mmol/l suffices'. Two recent JAMA papers lend support to both views. So what to believe? The issue is whether those with an achieved low LDL level (< 1.8 mmol/l) carry a lower vascular risk than those with an LDL between 1.8 and 2.5 mmol/l. To study this, both groups need to be identical with respect to all other factors that determine the risk, and therefore only differ in their respective LDL levels. So it is all about adjustment for confounding. One paper (shows no benefit for a LDL level lower than 2.5 mmol/l) is based on individual participant information, allowing for optimal adjustment. The other paper (shows the lower, the better) is based on mean levels of trial groups, and cannot adequately adjust for confounding. These examples demonstrate that study design is very important.
authors.affiliation: Universitair Medisch Centrum Utrecht, Julius Centrum voor Gezondheidswetenschappen en Eerstelijnsgeneeskunde, Utrecht.
authors.forename: M L
authors.initials: ML
authors.lastname: Bots
mesh_terms: D008078:Cholesterol, LDL / Q000097:blood*; D006801:Humans; D012015:Reference Standards; D012016:Reference Values
chemical_list: D008078:Cholesterol, LDL