Fasting duration has a minimal impact on lipid levels, according to a study published on Nov. 12 in the Archives of Internal Medicine. The study’s findings indicate that there may not be a need for patients to fast during routine lipid level checks, which deviates

from the current guideline recommendation that patients fast for nine to 12 hours before measurement.

 

After looking at six months' worth of lipid levels and fasting intervals from 209,180 patients, results showed that the mean levels of total cholesterol and high-density lipoprotein cholesterol differed little among individuals with various fasting times. The mean calculated low-density lipoprotein cholesterol levels showed slightly greater variations of up to 10 percent among groups of patients with different fasting intervals, and the mean triglyceride levels showed variations of up to 20 percent.

Recent research indicates that food intake may actually heighten accuracy when predicating adverse cardiovascular outcomes. However, studies also suggest that "lipid levels vary relatively little between the fasting and the nonfasting states and that the risk of coronary heart disease and strokes is similarly increased for both nonfasting and fasting lipid levels." Given the disconnect between this research and the current guideline recommendations, the study set out to understand the true impact of fasting times on lipid levels.

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The authors note that their results were consistent with previous findings, however, due to several limitations of the research. They emphasize the importance of obtaining additional data on lipid levels and fasting times to ensure a complete understanding of the relationship.

In a related commentary, Amit V. Khera, MD, and Samia Mora, MD, MHS, note, "a growing body of evidence from observational studies and statin clinical trials suggests that non-fasting or fasting blood draws may be used for cardiovascular risk assessment and therapeutic decisions, especially when lipid subfractions other than LDL-C (eg, the total to HDL-C ration or non-HDL-C) are emphasized." However, "further validation studies are needed before a nonfasting lipid testing strategy is universally endorsed," they add.

In a separate commentary, J. Michael Gaziano, MD, MPH, weighs in on the findings, "the incremental gain in information of a fasting profile is exceedingly small for total and HDL cholesterol values and likely does not offset the logistic impositions placed on our patients, the laboratories, and our ability to provide timely counseling to our patients." He continues, "this, in my opinion, tips the balance toward relying on nonfasting lipid profiles as the preferred practice."

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