Two lipid-related studies appearing in JAMA today will be of interest to many CardioBrief readers:
In the first study, researchers found that long term statin use (the effect didn’t kick in until after a year or a year and a half of treatment) was associated with a reduced incidence of gallstone disease and cholecystectomy. It won’t be a big surprise, since most gallstones are composed largely of cholesterol, but this is the biggest and best study yet of this important subject.
In the second study, researchers found that lipid assessment can be greatly simplified by measuring–without fasting– either total and HDL cholesterol levels or apolipoproteins.
The combined analysis of over 300,000 subjects from 68 long-term studies also found that triglycerides did not provide additional information. The British researchers wrote that “current discussions about whether to measure cholesterol levels or apolipoproteins in vascular risk assessment should hinge more on practical considerations (e.g., cost, availability, and standardization of assays) than on major differences in strength of epidemiological associations.”
Here are the JAMA press releases:
Long-Term Statin Use Associated With Decreased Risk of Gallstones Requiring Surgery
CHICAGO—Use of the cholesterol-lowering drugs statins for more than a year is associated with a reduced risk of having gallstones requiring surgery, according to a study in the November 11 issue of JAMA.
In developed countries, approximately 10 percent to 20 percent of white adults have gallstones, which can cause pain and complications. Gallstone disease is a leading cause of gastrointestinal tract illness and inpatient admission in western countries and represents a serious burden for health care systems worldwide. More than 700,000 cholecystectomies (removal of the gallbladder) are performed annually in the United States, according to background information in the article.
Gallstones are classified as either cholesterol (80 percent-90 percent) or pigment stones (10 percent-20 percent), with cholesterol stones formed on the basis of cholesterol-supersaturated bile. “Statins decrease hepatic [liver] cholesterol biosynthesis and may therefore lower the risk of cholesterol gallstones by reducing the cholesterol concentration in the bile. Data on this association in humans are scarce,” the authors write.
Michael Bodmer, M.D., M.Sc., of University Hospital, Basel, Switzerland, and colleagues conducted a large long-term observational study to examine the association between statin use and the risk of developing gallstone disease followed by cholecystectomy. The study included data from between 1994 and 2008 from the UK-based General Practice Research Database. A total of 27,035 patients with cholecystectomy and 106,531 matched controls were identified, including 2,396 patients and 8,868 controls who had statin use.
The researchers found that compared with nonuse, current statin use (last prescription recorded within 90 days before the first-time diagnosis of the disease) was 1.0 percent for patients and 0.8 percent for controls for 1 to 4 prescriptions; 2.6 percent vs. 2.4 percent for 5 to 19 prescriptions, and 3.2 percent vs. 3.7 percent for 20 or more prescriptions.
“This large observational study provides evidence that patients with long-term statin use have a reduced risk of gallstone disease followed by cholecystectomy compared with patients without statin use. However, the odds ratio was not decreased for patients with short-term statin use but started to decrease after 5 prescriptions, reflecting approximately 1 to 1.5 years of treatment. The risk estimate was consistent across age and sex groups. Adjustment for important risk factors for gallstone disease did not materially alter the results,” the researchers write.
The authors add that the observed risk reduction suggests a class effect for all statins, and that there was a tendency toward a lower risk of gallstone disease for high-dose statin use compared with low-dose exposure. A substantially increased gallstone risk with cholecystectomy was found for patients with high body mass indexes and for patients with estrogen use.
“Our findings may be of clinical relevance given that gallstone disease represents a major burden for health care systems,” the researchers conclude.
(JAMA 2009;302[18]:2001-2007.)
Findings Suggest Lipid Assessment in Vascular Disease Can Be Simplified, Without the Need to Fast
CHICAGO—Lipid assessment in vascular disease can be simplified by measuring either total and HDL cholesterol levels or apolipoproteins, without the need to fast and without regard to triglyceride levels, according to a study in the November 11 issue of JAMA.
Reliable assessment of the associations of major blood lipids and apolipoproteins with the risk of vascular disease is important for the development of screening and therapeutic strategies, according to background information in the article. “Expert opinion is divided about whether assessment of apolipoprotein AI (apo AI) and apolipoprotein B (apo B) should replace assessment of high-density lipoprotein cholesterol (HDL-C) and total cholesterol levels in assessment of vascular risk. Although there is agreement about the value of reducing low-density lipoprotein cholesterol (LDL-C or, approximately analogously, non-high-density lipoprotein cholesterol [non-HDL-C]), uncertainty persists about the merits of modification or measurement of triglycerides or HDL-C,” the authors write.
John Danesh, F.R.C.P., of the Emerging Risk Factors Collaboration Coordinating Centre, University of Cambridge, United Kingdom, and colleagues conducted a study to estimate of the associations of major lipids and apolipoproteins in relation to coronary heart disease (CHD) and ischemic stroke. The study included data on 302,430 individuals without initial vascular disease from 68 long-term prospective studies, mostly in Europe and North America. During the follow-up periods, there were 8,857 nonfatal myocardial infarctions (heart attacks), 3,928 CHD deaths, 2,534 ischemic strokes, 513 hemorrhagic strokes and 2,536 unclassified stokes.
The researchers write that the analysis indicated several findings. “First, hazard ratios (HRs) with non-HDL-C and HDL-C were nearly identical to those seen with apo B and apo AI. This finding suggests that current discussions about whether to measure cholesterol levels or apolipoproteins in vascular risk assessment should hinge more on practical considerations (e.g., cost, availability, and standardization of assays) than on major differences in strength of epidemiological associations.”
“Second, HRs for vascular disease with lipid levels were at least as strong in participants who did not fast as in those who fasted. Third, HRs were similar with non-HDL-C as with directly measured LDL-C. Finally, in contrast with previous findings based on much less data, triglyceride concentration was not independently related with CHD risk after controlling for HDL-C, non-HDL-C, and other standard risk factors, including null findings in women and under nonfasting conditions. Hence, for population-wide assessment of vascular risk, triglyceride measurement provides no additional information about vascular risk given knowledge of HDL-C and total cholesterol levels, although there may be separate reasons to measure triglyceride concentration (e.g., prevention of pancreatitis).”
“The current analysis of more than 300,000 people has demonstrated that lipid assessment in vascular disease can be simplified by measurement of either cholesterol levels or apolipoproteins without the need to fast and without regard to triglyceride,” the authors conclude.
(JAMA 2009;302[18]:1993-2000.)
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