A comparison of clinical outcome studies among cholesterol-lowering agents

Do clinicians recommend aspirin to patients for primary prevention of cardiovascular disease?

BACKGROUND

The United States Preventive Services Task Force (USPSTF) released updated guidelines in 2009 recommending aspirin to prevent myocardial infarction among at-risk men and stroke among at-risk women.

OBJECTIVE

Our aim was to examine clinician aspirin recommendation among eligible persons based on cardiovascular risk scores and USPSTF cutoffs.

DESIGN

We used across-sectional analysis of a current nationally representative sample.

PARTICIPANTS

Participants were aged 40 years and older, and in the National Health and Nutrition Examination Survey (NHANES) (2011-2012).

MAIN MEASURES

We determined aspirin eligibility for cardiovascular disease (CVD) prevention for each participant based on reported and assessed cardiovascular risk factors. We assessed men's risk using a published coronary heart disease risk calculator based on Framingham equations, and used a similar calculator for stroke to assess risk for women. We applied the USPSTF risk cutoffs for sex and age that account for offsetting risk for gastrointestinal hemorrhage. We assessed clinician recommendation for aspirin based on participant report.

RESULTS

Among men 45-79 years and women 55-79 years, 87 % of men and 16 % of women were potentially eligible for primary CVD aspirin prevention. Clinician recommendation rates for aspirin among those eligible were low, 34 % for men and 42 % for women. Rates were highest among diabetics (63 %), those 65 to 79 years (52 %) or those in poor health (44 %). In contrast, aspirin recommendation rates were 76 % for CVD secondary prevention. After accounting for patient factors, particularly age, eligibility for aspirin prevention was not significantly associated with receiving a clinician's recommendation for aspirin (AOR 0.99 %; CI 0.7-1.4).

CONCLUSIONS

Despite an "A recommendation" from the USPSTF for aspirin for primary prevention of CVD, the majority of men and women potentially eligible for aspirin did not recall a clinical recommendation from their clinician.

The effects of concurrent atorvastatin therapy on the pharmacokinetics of intravenous midazolam

Midazolam is a commonly used anaesthetic agent and is metabolised by the 3A4 isoform of the cytochrome P450 enzyme system. Atorvastatin is also metabolised by cytochrome P450 3A4 and, in vitro, atorvastatin inhibits the cytochrome P450 3A4-mediated metabolism of mexazolam. We hypothesised that concurrent administration of atorvastatin and midazolam would result in altered midazolam pharmacokinetics. Fourteen patients scheduled to undergo general anaesthesia for elective surgery were recruited in a matched pair design to receive intravenous midazolam (0.15 mg.kg-1). Of these patients, seven were taking long-term atorvastatin. Atorvastatin patients demonstrated a greater area under the curve (889.4 (standard deviation 388.6) ng-h.ml-1) vs. control patients (629.1 (standard deviation 197.2) ng-h.ml-1) (p < 0.05). Patients taking atorvastatin also demonstrated a decreased clearance (0.18 (standard deviation 0.08) l-kg. h-1) vs. control patients (0.27 (standard deviation 0.08) l-kg.h-1) (p < 0.05). This study suggests that chronically administered atorvastatin decreases the clearance of intravenously administered midazolam.

Statin effects on cholesterol micro-domains in brain plasma membranes

Recent epidemiological studies revealed inhibitors of the hydroxymethylglutaryl-coenzyme A reductase, so-called statins, to be effective in lowering the prevalence of Alzheimer's disease (AD). In vitro, statins strongly reduced the cellular amyloid beta-protein load by modulating the processing of the amyloid beta precursor protein. Both observations are probably linked to cellular cholesterol homeostasis in brain. So far, little is known about brain effects of statins. Recently, we could demonstrate that treatment of mice with the lipophilic compound lovastatin resulted in a discrete reduction of brain membrane cholesterol levels. To follow up these findings, we subsequently carried out a further in vivo study including lovastatin and simvastatin as lipophilic agents, as well as pravastatin as a hydrophilic compound, focussing on their efficiency to affect subcellular membrane cholesterol pools in synaptosomal plasma membranes of mice. In contrast to the hydrophilic pravastatin, the lipophilic lovastatin and simvastatin strongly reduced the levels of free cholesterol in SPM. Interestingly, lovastatin and pravastatin but not simvastatin significantly reduced cholesterol levels in the exofacial membrane leaflet. These changes were accompanied by modified membrane bulk fluidity. All three statins reduced the expression of the raft marker protein flotillin. Alterations in transbilayer cholesterol distribution have been suggested as the underlying mechanism that forces amyloidogenic processing of APP in AD. Thus, our data give some first insight in the mode of action of statins to reduce the prevalence of AD in clinical trials.

Pharmacoeconomics of lipid-lowering drugs

The widespread use and high cost of lipid-lowering drugs have resulted in numerous investigations of their cost effectiveness. Pharmacoeconomic analyses have considered initiation of treatment, maintenance therapy, and long-term outcomes of lipid-lowering therapy. Analyses have yielded a number of consistent messages, but the story continues to evolve as new trials, models, and drugs are introduced. Certain medications are more efficacious and associated with more cost-effective lipid-lowering therapy initiation. Other medications are lower priced and may be more cost effective for maintenance, contingent upon having achieved lipid-lowering goals. Finally, some medications have proven long-term cost effectiveness in trials and comparative cost effectiveness in models. Research is certain to further our understanding of the costs of lipid-lowering therapy and the methods needed to optimize expenditures.