Nonfasting
Triglyceride Levels Predict Cardiovascular Risk
Nonfasting triglyceride (TG) levels are easier
to obtain than fasting TG levels and may offer
significant prognostic value.
That, according to the results of the Multiple
Risk Factor Intervention Trial (MRFIT) published
in the May 12 issue of the Archives of Internal
Medicine.
"It remains unclear whether hypertriglyceridemia
is an independent risk factor for coronary heart
disease (CHD), and whether fasting and nonfasting
[TG] levels are equally predictive," write
Lynn E. Eberly, PhD, and colleagues from the MRFIT
Research Group. "This work is, to our knowledge,
the first direct comparison — from the same
study cohort — of the prognostic importance
of fasting and nonfasting TG levels for fatal
and nonfatal CHD."
Of 12,866 men enrolled from 1973 to 1975 into
MRFIT who had fasting and nonfasting TG levels
measured at baseline, 2,809 were followed up for
CHD incidence and death.
Average TG levels were 187 mg/dL (2.11 mmol/L)
fasting and 284 mg/dL (3.21 mmol/L) nonfasting.
Prevalence of hypertriglyceridemia, defined as
at least 200 mg/dL (2.26 mmol/L), was 31% for
fasting and 61% for nonfasting. Over an eight-year
period, there were 175 nonfatal or fatal CHD events,
and there were 328 CHD deaths during 25 years.
Compared with TG levels less than 200 mg/dL, hypertriglyceridemia
was associated with increased risk of of CHD mortality
(adjusted hazard ratio [HR], 1.24; P = .09 for
fasting; HR, 1.26; P = .07 for nonfasting). Fasting
and nonfasting TG levels were similarly predictive
of nonfatal or fatal CHD (HR, 1.64; P = .004 for
fasting; HR, 1.46; P = .03 for nonfasting).
The authors suggest that these associations for
fasting TG levels could be underestimated by 56%
because of regression dilution bias; this is especially
the case for nonfasting TG levels. Study limitations
also include failure to determine time since the
last meal for the nonfasting TG measurement.
"Greater ease of obtaining nonfasting than
fasting measurements, greater prevalence of hypertriglyceridemia
with nonfasting than fasting values, and similarly
increased risk with each indicate that nonfasting
TG levels may be more useful than fasting ones
for risk stratification," the authors write.
"Although multiple measurements may be required
for accurate classification, nonfasting readings
may provide information about risk that is not
apparent from fasting readings alone."
Arch Intern Med. 2003;163:1077-1083
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Did YOU KNOW:
Patients with type 2 diabetes appear no less sensitive
to myocardial ischemia than are comparable subjects
without diabetes, 25% of both, fail to experience
the warning signs, researchers report in the April
15th issue of the American Journal of Cardiology.
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