Plasma S-adenosylmethionine inversely tied to death risk in CAD

Plasma S-adenosylmethionine (SAM) is inversely associated with the risk of mortality in patients with coronary artery disease (CAD) after adjustment for homocysteine, S-adenosylhomocysteine (SAH), and other cardiovascular disease risk factors, a study has shown.

To determine the relationship between plasma SAM and mortality risk among CAD patients, the investigators measured baseline plasma SAM concentrations in 1,553 patients from the Guangdong Coronary Artery Disease Cohort between October 2008 and December 2011. Subsequently, they performed proportional hazards Cox analyses to establish associations between SAM and the risk of all-cause and cardiovascular deaths.

Of the 1,553 participants, 321 died, with 22 deaths from cardiovascular disease, over a median follow-up of 9.2 years (interquartile range, 8.5–10.2).

In multivariable adjusted analysis, patients in the lowest vs the highest quartile of SAM concentrations had a higher risk of all-cause death (hazard ratio [HR], 1.59, 95 percent confidence interval [CI], 1.14–2.21) and cardiovascular death (HR, 2.14, 95 percent CI, 1.41–3.27).

After fully adjusting for other cardiovascular risk factors, each 1-standard deviation (SD) decrease in SAM concentration remained associated with a higher risk of total death (HR, 1.42, 95 percent CI, 1.23–1.64) and cardiovascular death (HR, 1.66, 95 percent CI, 1.37–2.01).

In fully adjusted analyses, each 1-SD decrease in plasma SAM/SAH ratio, as the methylation index, also inversely correlated with the risk of all-cause (HR, 1.80, 95 percent CI, 1.42–2.29) and cardiovascular death (HR, 1.68, 95 percent CI, 1.29–2.19).

“SAM as methyl donors participates in methylation and is converted into SAH, which is a precursor of homocysteine,” the investigators said. “Increased plasma SAH and homocysteine are associated with increased risk of cardiovascular disease.”