© Copyright 2009 by the American Association for Clinical Chemistry

Nonfasting Lipids, Lipoproteins, and Apolipoproteins in Individuals With and Without Diabetes: 58 434 Individuals from the Copenhagen General Population Study

Anne Langsted and Børge G. Nordestgaard

March 2011

http://www.clinchem.org/cgi/content/full/57/3/482

© Copyright 2011 by the American Association for Clinical Chemistry

Journal ClubJournal Club

© Copyright 2009 by the American Association for Clinical Chemistry

IntroductionIntroduction

Diabetics have higher risk of atherosclerotic cardiovascular disease than nondiabetics

Lipid derangements in diabetics • High plasma triglycerides• Low HDL cholesterol• (High LDL cholesterol)

© Copyright 2009 by the American Association for Clinical Chemistry

IntroductionIntroduction

Fasting or nonfasting lipid measurementsA controversial subject

>In the general populationConcentrations of lipids, lipoproteins and apolipoproteins only differ minimally in fasting and nonfasting samples

>For diabeticsPresently unknownThe objective of this study

© Copyright 2009 by the American Association for Clinical Chemistry

QuestionsQuestions

What are the main mechanisms for developing atherosclerotic cardiovascular disease?

Why do diabetics have a particularly high risk of developing atherosclerotic cardiovascular disease?

© Copyright 2009 by the American Association for Clinical Chemistry

Materials and methodsMaterials and methods

Copenhagen General Population Study

Participants randomly selected from the general population of Copenhagen, Denmark

Total participants between 2003 and 2009N= 58434 With diabetes (self-reported, taking insulin or other antidiabetic medication, random plasma glucose >11 mmol/L)N= 2270

Denmark

© Copyright 2009 by the American Association for Clinical Chemistry

Materials and methodsMaterials and methods

Analyses

Fresh blood samples collected at Copenhagen University Hospital

Standard hospital assays (Konelab) used to measure glucose, total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, apolipoprotein A1, apolipoprotein B and albumin

Non-HDL cholesterol = total cholesterol – HDL cholesterol

If triglycerides <4 mmol/L, LDL cholesterol was calculated by the Friedewald equation

© Copyright 2009 by the American Association for Clinical Chemistry

Materials and methodsMaterials and methods

Statistical analyses

All analyses performed using Stata 10.

Student t-tests were used to identify differences in lipids, lipoproteins, apolipoproteins and albumin as a function of time since the last meal.

All t-tests were corrected for multiple comparison with the Bonferroni method.

© Copyright 2009 by the American Association for Clinical Chemistry

QuestionsQuestions

What are the criteria for a fasting blood sample? Are you allowed to drink anything before the sample is taken?

© Copyright 2009 by the American Association for Clinical Chemistry© Copyright 2009 by the American Association for Clinical Chemistry

ResultsResults

© Copyright 2009 by the American Association for Clinical Chemistry

ResultsResults

© Copyright 2009 by the American Association for Clinical Chemistry

ResultsResults

© Copyright 2009 by the American Association for Clinical Chemistry

QuestionsQuestions

What would be the advantages of measuring lipid profiles in the nonfasting state?How could this be implemented?

© Copyright 2009 by the American Association for Clinical Chemistry

DiscussionDiscussion

• Mean plasma triglycerides only increased a maximum of 0.2 mmol/L after normal food intake in both diabetic and nondiabetic individuals

• Reduction in LDL cholesterol observed after normal food intake in both diabetic and nondiabetic individuals most likely caused by hemodilution due to fluid intake

• Apolipoprotein B concentrations did not change after normal food intake

• Non-HDL cholesterol was found to be quite stable

Conclusions

© Copyright 2009 by the American Association for Clinical Chemistry

DiscussionDiscussionStill controversial whether lipid profiles should be measured fasting or nonfasting; present data suggest that nonfasting samples can be used in diabetics and nondiabetics alike

Nonfasting blood sampling would simplify the process for both patients and general practitioners/hospitals

In Denmark: nonfasting lipid measurements as a standard is recommended by the Danish Society for Clinical Biochemistry - and by 2010 implemented in most of the country

In Denmark: if nonfasting triglycerides are >4 mmol/L, the clinician can choose to measure triglycerides fasting. However, most do not use this option.

© Copyright 2009 by the American Association for Clinical Chemistry

DiscussionDiscussion

Editorial by Gerald F Watts and Jeffrey S Cohn:

Distinctions between screening, assessment, and treatment

For initial screening for dyslipidemia, nonfasting blood samples are sufficient

Recommend a fasting sample as the benchmark for risk assessment, diagnosis, and therapy of lipid disorders

- with consideration given to nonfasting samples in specific clinical circumstances like stable drug therapy