Lot of data on effect of lowering LDL cholesterol, using various drugs. As I've read it, the data pretty clearly shows that lowering LDL reduces cardiovascular (CV) events, and that using statins reduces CV events.
So there is a debate about whether doctors should aim to bring every patient down to a certain LDL number without regard to the patient's CV risk, or whether doctors should simply treat every patient who is at high CV risk without targeting a specific LDL number. Recent medical (AHA) guidelines recommend the latter.
There is also a debate about, if you're going to target a LDL number, how low that target should be. Recent large trial IMPROVE-IT showed that adding another drug on top of statins, to bring LDL from 70 to 50, did reduce CV events but only modestly.
My personal conclusion - not a doctor! I read this stuff for work purposes - is that if my LDL was clearly high (>150) I would bring it down, preferably through diet and exercise and not smoking and other lifestyle changes, then resorting to drugs (statins or other) if necessary. If my LDL was normal or borderline (100-120) I - personally - would not get too fussed about it.
Complicating this is that there are different types of LDL, small/dense vs large/not dense, and the CV risk comes from the former, but usually the LDL test you get is just total LDL not the subfractions.
Effects on 11-year mortality and morbidity of lowering LDL cholesterol with simvastatin for about 5 years in 20
20 536 patients at high risk of vascular and non-vascular outcomes were allocated either 40 mg simvastatin daily or placebo, using minimised randomisation. Mean in-trial follow-up was 5·3 years (SD 1·2), and post-trial follow-up of surviving patients yielded a mean total duration of 11·0 years (SD 0·6). The primary outcome of the long-term follow-up of HPS was first post-randomisation major vascular event, and analysis was by intention to treat.
During the in-trial period, allocation to simvastatin yielded an average reduction in LDL cholesterol of 1·0 mmol/L and a proportional decrease in major vascular events of 23% (95% CI 19–28; p<0·0001), with significant divergence each year after the first. During the post-trial period (when statin use and lipid concentrations were similar in both groups), no further significant reductions were noted in either major vascular events (risk ratio [RR] 0·95 [0·89–1·02]) or vascular mortality (0·98 [0·90–1·07]).
http://www.medscape.com/viewarticle/835030
The study [IMPROVE-IT] included more than 18 000 patients from 39 countries who were stable following ACS (<10 days). Patients were randomized to one of two treatment strategies: simvastatin 40 mg alone or simvastatin 40 mg plus ezetimibe 10 mg. They were followed for a minimum of 2.5 years or until the study investigators accrued 5250 clinical events.
At baseline, the mean LDL-cholesterol level among the ACS patients was 95 mg/dL in both treatment arms. With simvastatin 40 mg, LDL-cholesterol levels were reduced to 69.9 mg/dL at 1 year. The addition of ezetimibe 10 mg to simvastatin further lowered LDL-cholesterol levels, to 53.2 mg/dL at 1 year. Over 7 years, there remained a significant difference between the two treatments in the achieved LDL-cholesterol levels.
Over a period of 7 years, the addition of ezetimibe to simvastatin 40 mg reduced the primary end point—a composite of cardiovascular death, MI, unstable angina requiring rehospitalization, coronary revascularization, or stroke—by 6.4% when compared with patients who received simvastatin alone (P =0.016). The absolute reduction in risk over 7 years was 2.0%, with 32.7% in the ezetimibe/simvastatin arm experiencing a primary end point compared with 34.7% in the simvastatin arm.