By Harold L. Karpman, MD, FACC, FACP

Clinical Professor of Medicine, David Geffen School of Medicine, UCLA, Cardiovascular Medical Group

Dr. Karpman reports no financial relationships relevant to this field of study.

SYNOPSIS: When attempting to determine whether fasting or nonfasting lipid measurements are most appropriate in an individual patient, it is important to first think carefully about the clinical scenario and consider what question the results answer.

SOURCE: Driver SL, Martin SS, Gluckman TJ, et al. Fasting or nonfasting lipid measurements: It depends on the question. J Am Coll Cardiol 2016;67:1227-1234.

Requiring patients to fast before obtaining a lipid panel is of concern for some patients because of the potential inconvenience of prolonged fasting before, for example, an afternoon visit. Because of the inconvenience of obtaining fasting lipid studies on frequent occasions, Driver et al re-examined the need for obtaining fasting lipid and lipoprotein measurements in various clinical scenarios.1

Rather than focusing on the best answer (i.e., fasting or nonfasting), the authors suggested that it was more important first to think carefully about what question is to be answered with the results. The authors concluded that different questions arise depending on the clinical scenario presented by the patient. Different factors to consider include: 1) is the acquired data to be used for estimating the initial global risk from atherosclerotic cardiovascular disease (ASCVD) in the typical primary prevention patient; 2) screening for familial hypercholesterolemia in a patient with a strong family history of premature ASCVD or other genetic dyslipidemia; 3) attempting to clarify a diagnosis of metabolic syndrome; 4) assessing residual risk in a treated patient; 5) diagnosing and treating patients with suspected hypertriglyceridemic pancreatitis; or 6) diagnosing hypertriglyceridemia. Fasting lipid results initially were required when hypertriglyceridemia was studied in 1967, and fasting lipid measurements still were recommended in the third report of the national cholesterol education program.2,3

Driver et al concluded that when estimating the ASCVD risk in untreated primary prevention patients or when clarifying the diagnosis of a metabolic syndrome, nonfasting lipid studies were acceptable. However, fasting lipid studies were preferred or required when screening or following patients with a family history of genetic hyperlipidemia or premature ASCVD, when estimating residual risk for a treated patient, when assessing patients with or at risk for pancreatitis, or when diagnosing or following patients with hypertriglyceridemia. If a nonfasting triglyceride level is > 200 mg/dL, perform a follow-up fasting lipid panel.

COMMENTARY

When attempting to determine whether fasting or nonfasting lipids are most appropriate, it is important to first review the clinical scenario in individual patients and consider exactly what question is to be answered with the results. If a clinician follows the 2013 American College of Cardiology/American Heart Association guidelines, which suggested using a fixed dose of statin drugs for each risk category, minor differences in lipid results are not of great concern and, therefore, it makes little difference if these results are obtained in the fasting state.4 However, if the ATP III guidelines are followed, the treat-to-target strategy is to treat to achieve certain goals (i.e., low-density lipoprotein cholesterol < 100 mg/dL for primary prevention in high-risk individuals, < 130 mg/dL for those at intermediate risk, and < 160 mg/dL for low-risk individuals). Therefore, clinicians must obtain fasting lipid measurements. Finally, it is important to recognize that there is never a benefit to obtaining nonfasting lipid studies except for a minor convenience to the patient on occasion. Therefore, it would seem appropriate to recommend that all lipid studies be obtained in the fasting state unless it is inconvenient or impossible to do so in the individual patient under study.

REFERENCES

  1. Driver SL, Martin SS, Gluckman TJ, et al. Fasting or nonfasting lipid measurements: It depends on the question. J Am Coll Cardiol 2016;67:1227-1234.
  2. Fredrickson DS, Levy RI, Lees RS. Fat transport in lipoproteins — an integrated approach to mechanisms and disorders. N Engl J Med 1967;276:148-156.
  3. Third Report of the National Cholesterol Education Program (CAP and CEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III) final report. Circulation 2002;106:3143-3421.
  4. Goff DC Jr, Lloyd-Jones DM, Bennett G, et al. 2013 American College of Cardiology/American Heart Association guideline on the assessment of cardiovascular risk: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation 2014;129(Suppl 2):S49-S73. doi: 10.1181. 1161/01.cir.0000437741.48606.98.