Fasting before lipid tests – Not an absolute requirement?

Fasting prior to routine blood lipid tests may be unnecessary, according to new research.

The findings have stirred a debate, with some physicians proposing to do away with the current guidelines that recommend measuring fasting lipid levels, while others are advising caution.

Earlier studies have suggested that non-fasting lipid profiles change minimally in response to food intake and may be superior to fasting levels in predicting adverse cardiovascular outcomes, said study authors Drs Davinder Sidhu and Christopher Naugler of the University of Calgary, Alberta, Canada. [Arch Intern Med 2012;172:1707-1710]

To confirm the findings in a large community cohort, they conducted a cross-sectional examination of laboratory data from 209,180 subjects, of whom 111,048 were women. The data included records of the subjects’ fasting durations, which ranged from 1 to 16 hours, and their lipid level measurements, over a 6-month period in 2011. Fasting time was stratified into hourly intervals from 1 to 16 and correlated with lipid results including mean high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, total cholesterol (TC), and triglycerides (TG).

On analysis, the researchers found that the mean levels of TC and HDL cholesterol differed little between individuals with various fasting times. Specifically, these levels varied by less than 2 percent for TC and HDL cholesterol, less than 10 percent for calculated LDL cholesterol, and by less than 20 percent for TG.

“This finding suggests that fasting for routine lipid level determinations is largely unnecessary,” said the researchers.

In an accompanying editorial, Dr. J. Michael Gaziano of Brigham and Women’s Hospital, Harvard Medical School in Boston, Massachusetts, US, said 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, laboratories, and our ability to provide timely counseling to our patients.

Therefore, although the study showed interesting results with potential application of non-fasting lipid measurements, Ho did not foresee a change in the requirement for fasting lipid sample to accurately determine the LDL levels, which remains the current primary lipid treatment target. [Source]


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