Tuesday, October 29, 2019

Retrospective #255: “Risk Prediction with triglycerides…”

Virtually everyone who has blood taken at the doctor’s office these days gets a standard “lipid” or cholesterol panel. Your doctor receives assayed values for Total Cholesterol (TC) and High-density lipoproteins (HDL), the so-called “good” cholesterol, and, nowadays, non-HDL cholesterol in lieu of very low-density lipoproteins. The panel also includes a related assay, triglycerides, a fat molecule circulating in your blood. In addition to these measurements, the lipid panel reports on Low-density lipoproteins (LDL), but it is a calculated value, not an assayed, direct measurement.
If it’s over 200mg/dL, your doctor will use the Total Cholesterol result to try to persuade you to take a statin. Statins do lower both TC and LDL cholesterol, the so-called “bad” cholesterol, because TC = HDL + LDL + TG/5). This is a dubious benefit for virtually everyone except those with diagnosed coronary artery disease (CAD). In patients with existing coronary artery disease, statins are indicated for secondary prevention, to prevent a heart attack.
Most lipid panels also include a ratio, Total Cholesterol to HDL (TC/HDL), as a cardiovascular “risk indicator” for events such as heart attack, stroke, and death. However, in “Retrospective #27,” I presented the case that the strongest predictor of a heart attack is the ratio of triglycerides to HDL cholesterol, or TG/HDL. That column, written eight years ago, applies to the general “healthy” population and has been one of the most popular I have written.
A 2014 study, published in Clinical research in cardiology: official journal of the German Cardiac Society, provides a fresh look at “Risk prediction with triglycerides in patients with stable coronary disease on statin treatment” (my emphasis). The aim of the study was “to analyze the role of fasting and postprandial triglycerides (TG) as risk modifiers in patients with coronary artery disease (CAD).” The trial used measurements of oral triglyceride and glucose tolerance in 514 patients with stable CAD, confirmed by angiography, 95% of whom were treated with a statin.
After 48 months follow-up, using fasting and postprandial measurements and primary outcomes of cardiovascular death and hospitalizations, the researchers sought to determine if either fasting and/or postprandial serum triglycerides were a risk indicator and could predict the primary outcome. The results were surprising.
“CONCLUSIONS: Fasting serum triglycerides >150 mg/dL INDEPENDENTLY predict cardiovascular events in patients with coronary artery disease on guideline-recommended medication [statin drugs]. Assessment of postprandial TG does not improve risk prediction compared to fasting TG in these patients.”
The RESULTS were unequivocal. For fasting TG >150 vs. <106 mg/dL, the hazard ratio (HR) was 1.79. Translation: If you have CAD and are taking a statin, and your triglycerides are over 150 mg/dL, you have an ~80% greater chance of dying or being hospitalized for CAD over 4 years than if your triglycerides are <106/mg/dL. That is stunning.
The analysis then concluded, “Risk prediction by TG was INDEPENDENT of traditional risk factors, medication, glucose metabolism, [and] LDL- and HDL-cholesterol. Total cholesterol [and] LDL- and HDL-cholesterol concentrations were not associated with the primary outcome [cardiovascular death and hospitalizations].”
MY TAKEAWAY: If you have been diagnosed with coronary artery disease (CAD), your doctor will surely prescribe a statin, the guideline-recommended medication, and you should take it. But remember that your fasting serum triglycerides are an INDEPENDENT risk factor. Fortunately, they are also a MODIFIABLE risk factor, which is to say, i.e., one that YOU can change. But there’s no magic bullet. Prescriptions for Niacin and fibrates work for some people, and may be indicated for very high TGs, but the best way to lower your fasting serum triglycerides and to keep them low is with Omega 3 fatty acids (2g fish oil/day) and significantly LOWERING THE CARBOHYDRATES in your diet. I started out “borderline,” but my most recent TGs have been 51, 55, 34, 49, 47, 58, 54, 56, 65, 53, 31, 38, 52, 49, 50 and 34.
Your doctor is not likely to have seen this research from the German Cardiac Society. My intrepid editor found it.  Besides, current guidelines regard as “borderline” a fasting serum triglyceride from 150- 199 mg/dL, so your doctor will probably say something like, “We’ll have to watch that.”  But remember, the hazard ratio for TGs above 150 mg/dL, for people with CAD and taking a statin, was 1.79 (80% greater risk). Do you want to become a statistic?

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