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Thursday, October 10, 2013

The Friedewald and Iranian equations: Fasting triglycerides can seriously distort calculated LDL

Common lipid profiles offer LDL cholesterol steps primarily based on equations that normally have the following as their inputs (or unbiased variables): overall cholesterol, HDL cholesterol, and triglycerides.

Sure, LDL cholesterol is not measured immediately in standard lipid profile exams! This is certainly stunning, given that cholesterol-reducing medicines with unfavorable side effects are usually approved based mostly on believed (or "fictitious") LDL cholesterol stages.

The most widespread of these equations is the Friedewald equation. Via the Friedewald equation, LDL cholesterol is calculated as follows (exactly where TC = whole cholesterol, and TG = triglycerides). The inputs and outcome are in mg/dl.

    LDL = TC – HDL – TG / 5

Right here is 1 of the troubles with the Friedewald equation. Allow us believe that an individual has the adhering to lipid profile quantities: TC = two hundred, HDL = fifty, and trigs. = a hundred and fifty. The calculated LDL will be a hundred and twenty. Permit us presume that this very same personal reduces triglycerides to fifty, from the preceding one hundred fifty, maintaining all of the other steps constant. This is a significant improvement. Even so, the calculated LDL will now be 140, and a medical doctor will notify this man or woman to contemplate using statins!

There is evidence that, for men and women with low fasting triglycerides, a a lot more specific equation is one particular that has arrive to be known as the “Iranian equation”. The equation has been proposed by Iranian scientists in an article published in the Archives of Iranian Drugs (Ahmadi et al., 2008), hence its nickname. By means of the Iranian equation, LDL is calculated as follows. Yet again, the inputs and end result are in mg/dl.

    LDL = TC / 1.19 + TG / one.nine – HDL / 1.one – 38

The Iranian equation is dependent on linear regression modeling, which is a great indicator, although I would have favored it even better if it was based mostly on nonlinear regression modeling. The explanation is that interactions amongst variables describing well being-associated phenomena are often nonlinear, leading to biased linear estimations. With a good nonlinear examination algorithm, a linear connection will also be captured that is, the “curve” that describes the connection will default to a line if the relationship is truly linear (see: warppls.com).

In any case, an on the internet calculator that implements each equations (Friedewald and Iranian) is connected here it was the prime Google hit on a look for for “Iranian equation LDL” at the time of this post’s creating.

As you will see if you consider it, the on-line calculator connected above is useful in displaying the distinction in calculated LDL cholesterol, utilizing equally equations, when fasting triglycerides are quite minimal (e.g., below fifty).

The Iranian equation yields large values of LDL cholesterol when triglycerides are large considerably larger than people created by the Friedewald equation. If these are not overestimations (and there is some proof that, if they are, it is not by a lot), they explain an alarming metabolic sample, because substantial triglycerides are linked with modest-dense LDL particles. These particles are the most potentially atherogenic of the LDL particles, in the presence of other variables these kinds of as chronic inflammation.

In other words, the Iranian equation offers a clearer notion than the Friedewald equation about the unfavorable wellness consequences of large triglycerides. You want a huge number of small-dense LDL particles to have a high quantity of LDL cholesterol.

An even much more precise evaluate of LDL particle configuration is the VAP take a look at this publish has a hyperlink to a PDF file with a sample VAP test report.

Reference:

Ahmadi SA, Boroumand MA, Gohari-Moghaddam K, Tajik P, Dibaj SM. (2008). The affect of minimal serum triglyceride on LDL-cholesterol estimation. Archives of Iranian Drugs, 11(3), 318-21.
Title: The Friedewald and Iranian equations: Fasting triglycerides can seriously distort calculated LDL
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Posted by: Admin Updated at: 11:33 PM

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