Summary
Homocysteine isa risk factor for cardiovascular disease and venous thrombosis. Clinical
guidelines differ in their recommendation whether or not to measure homocysteine after
methionine loading. In this study, we investigated the added value of the methionine
loading test next to fasting homocysteine levels for identifying subjects at risk
for venous thrombosis or cardiovascular disease, using Receiver Operating Characteristic
(ROC) curves.The analysis was performed in 185 patients with recurrent venous thrombosis,
130 patients with cardiovascular disease and 601 controls.The discriminatory power
of the fasting homocysteine measurement alone for identifying subjects at risk of
venous thrombosis expressed as the area under the ROC curve (AUC) was 0.61 (95%CI
0.56-0.66). Using both a fasting homocysteine measurement and a methionine loading
test together yielded a similar AUC of 0.65 (95%CI 0.60-0.69), indicating no added
value of methionine loading next to fasting homocysteine measurement in identifying
subjects at risk for thrombosis. Similar results where found for cardiovascular disease,
with anAUC of 0.62 (95%CI 0.57-0.67) for the fasting homocysteine measurement alone
and an AUC of 0.62 (95%CI 0.57-0.67) for the combination of both the fasting and the
postload homocysteine measurement. The methionine loading test has no added value
next to measuring fasting homocysteine levels for identifying subjects at risk for
venous thrombosis or cardiovascular disease and for that reason should not be used
in clinical practice.
Keywords
Methionine loading test - hyperhomocysteinemia - homocysteine - venous thrombosis
- ROC curve