Requiring patients to fast for 8 to 12 hours before a lipid panel blood draw is common practice, but fasting adds no clinical value and is an unnecessary burden on patients, researchers said.
Analysis of data from the National Health and Nutrition Survey III (NHANES-III) revealed no significant difference between fasting and nonfasting LDL cholesterol levels when it came to predicting all-cause and cardiovascular mortality, New York University associate professor of medicine Sripal Bangalore, MD, and colleagues wrote in Circulation.
The study is not the first to find no benefit for fasting prior to a lipid panel blood draw. Another population analysis, published in Archives of Internal Medicine in 2012, failed to show an impact on lipid panel outcomes associated with the practice, and researchers concluded that fasting for routine lipid levels is “largely unnecessary.”
Many national and international guidelines for cholesterol management do recommend fasting blood draws, however, including the 2013 joint LDL cholesterol measurement recommendations of the American College of Cardiology and the American Heart Association.
“I think it’s time to change this recommendation, which is based on expert consensus without any data to back it up,” Bangalore told. “Fasting is inconvenient for the patient, and doing away with it could simplify the process of assessing patient risk.”
Bangalore said abandoning the fasting requirement could speed up the process of identifying and treating patients who need to be on statin therapy.
“When we tell them, ‘You have to come back at a later date to have your fasting lipid panel checked,’ many times patients don’t have the time or they don’t come back,” he said.
He added that fasting could even put diabetic patients at risk for hypoglycemia.
“During a 24-hour period people spend most of their time in a nonfasting state,” he said. “When we ask them to fast it is an artificial situation. To me it’s like studying for an exam to do well on a test. It is an artificial situation.”
Fasting and Nonfasting LDL Similar
Bangalore and colleagues analyzed data derived from 16,161 NHANES-III participants (surveyed between 1988 and 1994), representing more than 172 million adults in the U.S. Participants were excluded from the analysis of LDL cholesterol calculations when data were missing for HDL cholesterol, total cholesterol, or triglyceride levels and when triglyceride levels were 400 mg/dL or more.
‘Enough to Change Clinical Practice’
“Our study suggests that a nonfasting LDL cholesterol measurement offers a more convenient method of phlebotomy while preserving the prognostic value of the test,” the researchers concluded, adding that the fact that no difference in outcomes were seen for fasting and nonfasting triglycerides and total cholesterol, as well as LDL, should prompt health policymakers to revisit recommendations calling for fasting lipid profiles.
In the absence of new research showing fasting to offer advantages over nonfasting prior to lipid panel blood draws, Bangalore said physicians should not be telling patients to fast.
“This (study) along with a few others that have been published is compelling enough to change clinical practice,” he said. “I would say, yes, research is needed, but research is needed only to show that fasting is a better prognostic indicator…. If we want to do what we have been doing, we need research to actually prove that it is more efficacious.”
