Is fasting before a lipid panel necessary?

Consuming nothing but water for eight to 12 hours before a lipid panel has been common practice, but do patients really need to go hungry?

In a review of nonfasting versus fasting lipid profiles, Borge G. Nordestgaard, MD, said the answer is a resounding “no.”

“With the current evidence base, it could be argued that the use of nonfasting lipid profiles is evidence-driven, whereas continued use of fasting lipid profiles is largely belief-driven,” Nordestgaard, with Copenhagen University Hospital in Denmark, wrote in the Journal of the American College of Cardiology.

“Indeed, a main argument for keeping fasting lipid profiles is that ‘We have always done it that way!’ when today, prospective evidence from more than 300,000 individuals is available suggesting that nonfasting lipid profiles are as good as, if not better than, fasting lipid profiles in predicting future cardiovascular events.”

Nordestgaard was referring to a pooled analysis of 20 studies comprising 103,353 subjects who didn’t fast and 48 studies with a combined 199,076 subjects who did. In those studies, the ability to predict coronary heart disease using nonfasting lipid tests was 31 percent greater (hazard ratio 1.72 vs. 1.41) than in fasting lipid tests.

In the author’s own research—the Copenhagen General Population Study—changes in all lipid panel readings based on whether a patient fasted or not were found to be clinically insignificant.

From a patient’s perspective, Nordestgaard argued, changing a dietary routine is impractical and could increase the risk of hypoglycemia in diabetics. Fasting requirements also lead to unnecessary return visits and an inordinate amount of appointments being scheduled in the morning, which can hinder patient flow in laboratories.

“For patients, laboratories, and clinicians alike, nonfasting lipid profiles represent a simplification without negative implications for prognostic, diagnostic, and therapeutic options for cardiovascular disease prevention,” Nordestgaard wrote.

Several societies in Denmark, the United Kingdom, Europe, Canada, Brazil and the U.S. have endorsed nonfasting lipid profiles since 2009. The American Heart Association was one of the first to do so in 2011, and has since been followed by the European Society of Cardiology (2016) and the American Association of Clinical Endocrinologists & American College of Endocrinology (2017), among others.