Wednesday, March 13, 2019

Retrospective #25: Understanding Your Lipid (Cholesterol) Panel

I am not a doctor or other health care professional, but I can read a lab test report, especially one that provides a “Reference Range” and declares a result “IN range” or “OUT OF range,” plus other guidance, for each test ordered.
At each office visit, my doctor always orders a complete blood count (CBC) and a metabolic series, including a lipid panel, plus an A1c. And from time to time, he orders other specialty tests (High Sensitivity CRP, liver, thyroid, kidney, etc.). This column is going to be about understanding the lipid panel. That includes Total Cholesterol, HDL-C, LDL-C (calculated), Triglycerides, and the Total Cholesterol/HDL Ratio. Some panels now also include non-HDL-C.
Most people know the drill: “high” Total Cholesterol is not a good thing, and that there is “good” cholesterol (HDL-C) and a “bad” cholesterol (LDL-C), and that we should try to get our circulating triglyceride levels down. If we aren’t successful at doing this, by following the doctor’s advice to limit saturated fat and cholesterol containing foods, he (ort she) is going to prescribe a statin drug, which will lower LDL-C and, thereby, Total Cholesterol as well. We are going to be asked to support this gazillion dollar annual statin industry by taking Crestor, Lipitor, Zocor, or Simvastatin, the Zocor generic equivalent. (Remember, the original of this Retrospective was written in 2011.)
This column is not about the efficacy or safety of prescribing a statin. Personally, I disagree with the current practice. I do not think statins should be prescribed to anyone without diagnosed heart disease, or anyone over 75 or any woman whatsoever.  There is no proven benefit. But this column is about “understanding your lipid panel.”
 So, let us suppose that two people (or the same person, in two “snapshots” of lipid panels taken at different times) have identical Total Cholesterol, i.e.: 200mg/dl (milligrams per deciliter). One has an HDL-C = 40mg/dl, an LDL-C = 130mg/dl (calculated), a Triglyceride count of 150mg/dl, and a Total Cholesterol/HDL ratio of 5.0ALL FIVE OF THESE VALUES ARE BORDERLINE OUT-OF-RANGE. They would appear in BOLD in the “OUT-OF-RANGE” column on your lab report. Your doctor would tell you, according to my understanding of the “Standards of Medical Practice,” to cut down on all those saturated fat and cholesterol containing foods, and immediately start taking a statin.
Now let’s look at another lipid panel: Total Cholesterol also 200mg/dl, HDL-C = 80mg/dl, LDL-C = 110mg/dl (calculated), Triglycerides = 50mg/dl, and a Total Cholesterol/HDL ratio of 2.5. The only value that is borderline high in this panel is Total Cholesterol at 200mg/dl. Everything else is textbook WUNDERBAR! The LDL-C is above optimal (<100mg/dl), but it is a derived (calculated) value, not a DIRECT value (and in 2018 the formula changed).
The formula for LDL-C in the lipid panel, until 2018, was the Friedewald formula: LDL-C = Total Cholesterol – HDL-C – Triglycerides/5. And, if your doctor was worried about your less than optimal LDL’s (because of existing heart disease, other cardiac risk factors such as hypertension, obesity, metabolic syndrome or higher than “normal” fasting plasma glucose or A1c) he could order an LDL direct measurement or an even more sophisticated VAP test of LDL-C particle size (“A”= “large and buoyant” or “B” =“small and dense.”) Regardless, this lipid panel would NOT lead your doctor to prescribe a statin or suggest a dietary change. He would tell you, “Everything looks great!” and “Continue with whatever you are doing.” Think about that. Both TC’s (Total Cholesterols) are the same: 200mg/dl.
To recap: A Total Cholesterol test score of 200mg/dl on your lipid panel, with the first set of values above, will put you on dietary restrictions, and when that “prescription” doesn’t work, on a statin. That’s what happened to me. I followed my doctor’s dietary advice, it failed, and I was on a statin for 5 years, until I changed my diet…
But if you have a lipid panel like the second example, you’ll be your doctor’s “poster boy,” as I was after I’d been on a Very Low-Carb, High-Fat Way of Eating for a year, again on my doctor’s advice. Even though he started me on LOW-CARB, HIGH-FAT to lose weight, he doesn’t want to know what I eat. My doctor (a cardiologist) now just tells me to keep on doing what I’m doing. For him, it’s no more lectures – just smiles, and when the test results come back, a congratulatory phone call. For my doctor, my office visit is one of the “high points” of his day, he’s told me. 

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