Low homoarginine levels linked to increased CV mortality risk
MedWire News: Low homoarginine levels in patients referred for coronary angiography (CA) or undergoing hemodialysis are associated with increased risk for cardiovascular (CV) and all-cause mortality, research indicates.
"The present results, which indicate a strong adjusted association of homoarginine with CV outcomes in two independent patient cohorts, suggest homoarginine as a potential new risk factor, with various pathomechanisms being of particular interest," comment Christoph Wanner, from University Hospital Würzburg in Germany, and team.
Wanner and colleagues measured the homoarginine levels of clinically stable patients referred for coronary angiography (CA, n=3305) and diabetic patients treated by hemodialysis for less than 2 years (n=1244).
Writing in the journal Circulation, the team reports that over a median follow-up period of 7.7 years, 766 CA patients (23.2%) died, 482 due to a CV cause.
Of the hemodialysis patients, 608 (48.4%) died over a median follow-up of 4 years, 307 of CV causes.
The mean homoarginine level among the hemodialysis patients was lower than that of the CA group, at 1.2 versus 2.6 µmol/l, respectively.
Wanner and team say that this finding is somewhat unexpected as "homoarginine is excreted by the kidney" and thus, patients with impaired kidney function would be expected to have elevated homoarginine levels.
However, they hypothesize that this finding "may be due to the fact that the kidney is one of the sites for the transaminidation of L-lysine to homoarginine."
After adjustment for potential confounders, such as age and gender, the team found that CA patients in the lowest homoarginine quartile (<1.85 µmol/l) had a 4.5- and 3.3-fold increase in risk for CV and all-cause mortality, respectively, compared with those in the highest quartile (>3.1 µmol/l).
Hemodialysis patients in the lowest homoarginine quartile (<0.87 µmol/l) had 2.2-fold increases in risk for both all-cause and CV mortality, compared with those in the highest homoarginine quartile (>1.4 µmol/l).
"It would be interesting to reproduce our findings in as-yet asymptomatic individuals," say Wanner and team.
They conclude: "Further studies are needed to elucidate the underlying mechanisms."
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By Lauretta Ihonor