Erythrocyte-bound apolipoprotein B in atherosclerosis and mortality

The binding of apolipoprotein (apo) B-containing lipoproteins to circulating erythrocytes (ery-apoB) is associated with a decreased prevalence of atherosclerosis. In this study, we evaluated ery-apoB as a possible prognostic factor in cardiovascular events and all-cause mortality, in a prospective cohort study.

Ery-apoB was measured by flow cytometry in subjects with and without cardiovascular disease (CVD). The primary endpoint was the cardiovascular event rate. Secondary endpoints were all-cause mortality and the combined endpoint of all-cause mortality and cardiovascular events (any event rate). A Cox regression analysis with univariate and multivariate analyses and Kaplan-Meier survival analysis was performed.

Follow-up data were available of 384 subjects. Subjects were divided according to high (> 2·0 au, n = 60), intermediate (0·2-2·0 au, n = 274) or low (< 0·2 au, n = 50) ery-apoB. Median follow-up was 1767 days (IQR 1564-2001). In univariate analysis, low ery-apoB was associated with increased all-cause mortality [HR 9·9 (1·2-79·0), P = 0·031] and any event rate [HR 3·4 (95% CI 1·3-8·7), P = 0·012]. In a Cox regression analysis, only a history of CVD was significantly associated with any event rate [HR 3·6 (1·6-8·0), P = 0·002], while low ery-apoB showed a trend [HR 2·4 (0·9-6·4), P = 0·07]. In a subgroup analysis, in subjects with a history of CVD, ery-apoB was significantly associated with all-cause mortality (log rank P = 0·021) and any event rate (log rank P = 0·009).

Low ery-apoB is associated with increased mortality and cardiovascular risk, especially in patients with a prior history of CVD. These subjects may benefit from more aggressive secondary prevention treatment.