Study compared same-patient fasting, nonfasting lipid values
Fasting generally doesn't impact lipid levels, and taking a lipid panel soon after eating does not appear to misclassify cardiovascular risk, according to a post hoc analysis of the ASCOT trial.
The associations between lipid levels and coronary events broadly stayed the same between fasting and nonfasting samples from the same individuals, reported investigators led by Samia Mora, MD, MHS, of Brigham and Women's Hospital and Harvard Medical School in Boston.
For example, the increase in risk of non-fatal MI or fatal coronary heart disease per 40 mg/dL increase in Friedewald equation-calculated LDL cholesterol was similar between nonfasting (HR 1.32, 95% CI 1.08-1.61) and fasting values (HR 1.28, 95% CI 1.07-1.55), the researchers showed in their paper published online in JAMA Internal Medicine.
"Furthermore, the very high agreement (94.8%) of ASCVD [atherosclerotic cardiovascular disease] risk classification categories for fasting and nonfasting samples suggests that risk assessment and treatment decisions for statin and antihypertensive therapies would be consistent whether lipid levels were measured in the fasting or nonfasting state," the group wrote.
The results back recent guideline recommendations to adopt nonfasting measurement of lipid levels in routine practice, Mora and colleagues argued.
Removing the requirement to skip food before a lipid panel should facilitate screening in more settings, commented Jennifer Robinson, MD, MPH, of the University of Iowa in Iowa City.
"If we can identify more familial hypercholesterolemia patients earlier in life to begin statin treatment, that would have a huge impact on reducing their lifetime risk of atherosclerotic cardiovascular disease," she said.
The analysis of ASCOT's lipid-lowering arm included the 8,270 patients who had fasting and nonfasting lipid levels available before randomization to atorvastatin (Lipitor) or placebo. Average at enrollment was 63.4, and 82.1% of the cohort were men.
Nonfasting samples were associated with modestly higher triglyceride levels and similar cholesterol levels as fasting ones.
Most study participants had no prior vascular disease. As was the case with the overall cohort, this primary prevention subgroup showed no change in cardiovascular risk whether they were assessed using fasting or nonfasting lipid measurements.
The ASCOT substudy "adds to the emerging consensus that, for most purposes, non-fasting lipid measurements are appropriate for treatment decisions. Although triglycerides were modestly higher, the decision on whether to treat with a statin is not substantially altered," commented Steven Nissen, MD, of the Cleveland Clinic.
"The only exceptions would be patients with very elevated triglycerides. In those situations, direct measurement of fasting LDL cholesterol would be indicated," he told MedPage Today.
Notably, the ASCOT trial had been terminated early (at a median 3.3 years of follow-up) due to early benefits observed with the statin. It also recruited relatively few non-white participants, which the authors cited as a limitation.
The ASCOT trial was funded by Pfizer.
Mora disclosed receiving grants from Pfizer, the National Heart, Lung, and Blood Institute, and the National Institute of Diabetes and Digestive and Kidney Diseases for this study; personal fees from Pfizer, Amgen, and Quest Diagnostics; and grants from Atherotech Diagnostics Lab outside of the study.
JAMA Internal Medicine
Source Reference: Mora S, et al "Association of nonfasting vs fasting lipid levels with risk of major coronary events in the Anglo-Scandinavian Cardiac Outcomes Trial-Lipid Lowering Arm" JAMA Intern Med 2019; DOI: 10.1001/jamainternmed.2019.0392
Read the original article on Medpage Today: Fasting Before CV Labs? Maybe Don't Bother