Individual Cholesterol Levels Vary in Short-Term
Apparent increases may be false positives
TUESDAY, May 6 (HealthDay News) -- Individual cholesterol level measurements vary by at least 7 percent in the short-term, and apparent increases in annual cholesterol level may be false positives in patients taking cholesterol-lowering drugs, according to an article published in the May 6 issue of the Annals of Internal Medicine.
Paul P. Glasziou, Ph.D., from the University of Oxford in the United Kingdom, and colleagues analyzed cholesterol level data in 9,014 patients with acute coronary syndromes in Australia and New Zealand, who had been randomly assigned to placebo or 40 mg of pravastatin. Patients were followed-up for five years.
The researchers found that there were small increases in within-person variability in both groups over time, varying by 7 percent to 11 percent. The long-term variation did not exceed the short-term variation for nearly four years. Cholesterol monitoring may lead to false positives in patients with levels that are 0.5 mmol/L or more (at least 19 mg/dL) under target for at least the first three years of treatment, they suggest.
"The signal-noise ratio in cholesterol level monitoring is weak," the authors conclude. "Independent of the office-visit schedule, the interval for monitoring patients who are receiving stable cholesterol-lowering treatment could be lengthened."