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Novel method offers more precise LDL assessment in high-risk patients
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A novel estimation of LDL provided accurate measurements, particularly in patients with low LDL and high triglycerides, according to a study published in Circulation.
“[These findings] show that the decisions happening in doctors’ offices around the world every day using LDL-C will be better decisions if laboratories provide a more precise LDL-C assessment,” Vasanth Sathiyakumar, MD, a medical resident at Johns Hopkins University, told Cardiology Today. “This is of utmost importance for patients at high risk for cardiovascular events such as those with [atherosclerotic] CVD plus diabetes who have LDL-C goals of below 70 mg/dL.”
Fasting, nonfasting samples
Researchers analyzed data from 1,545,634 participants with triglycerides less than 400 mg/dL. Participants either fasted for at least 10 to 12 hours before sample collection (62%; median age, 56 years; 47% men) or were nonfasting (38%; median age, 55 years; 42% men). LDL was estimated using the Friedewald equation or a novel method, which takes into consideration adjustable factors.
“The Friedewald equation uses a fixed ratio between triglycerides and very low-density lipoprotein-cholesterol and, therefore, cannot account for variations in triglyceride-enriched states such as in nonfasting samples,” Sathiyakumar told Cardiology Today. “This spurred us to develop a novel method of LDL-C estimation, which improved the fidelity of LDL-C across clinical LDL-C and triglyceride categories.”
Accuracy in the novel method ranges from 87% to 94% in both fasting and nonfasting participants, and the Friedewald equation varied from 71% to 93% (P .001).
In participants with estimated LDL levels less than 70 mg/dL, the novel method in the nonfasting group was 92% accurate vs. 71% with the Friedewald method (P < .001).
Differences of at least 10 mg/dL were seen in 19% of participants in the fasting group and 30% in the nonfasting group when comparing the Friedewald method and measuring cholesterol concentration in LDL. The novel method had similar degrees of error in 2% to 3% of participants regardless of the fasting status.
Accurate in high triglycerides
Accuracy decreased in participants with LDL less than 70 mg/dL as triglycerides increased with the Friedewald method (37% to 96%) vs. the novel method (82% to 94%).
The novel method was 82% accurate in participants who did not fast, had LDL less than 70 mg/dL and triglycerides ranging from 200 mg/dL to 399 mg/dL compared with 37% with the Friedewald method (P < .001). Differences of at least 10 mg/dL were seen in 73% of fasting and 81% of nonfasting participants when the Friedewald method was compared with measuring cholesterol concentration in LDL. These differences occurred in 25% of fasting and 20% of nonfasting participants with the novel method.
“Since the individual patient is the focus of clinical practice, the novel method is able to adapt with patient-specific [triglyceride] to VLDL-C ratios and, therefore, account for subtle differences even in particular patient groups,” Sathiyakumar told Cardiology Today. “Population-based assessments should, therefore, be applied with caution to individual patients.” – by Darlene Dobkowski
For more information:
Vasanth Sathiyakumar, MD , can be reached at vsathiy1@jhmi.edu.
Disclosure: Sathiyakumar reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.
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