Red blood cell fatty acid levels improve GRACE score prediction of 2-yr mortality in patients with myocardial infarction

Abstract

Background Blood omega-3 and omega-6 fatty acid levels have been associated with reduced risk for total mortality in patients with stable coronary heart disease (CHD), but their relationships with mortality in the setting of myocardial infarction (MI) are unknown. Objective To determine the association between red blood cell (RBC) fatty acid levels measured at admission and 2-year mortality in MI patients, independent of the GRACE risk score, a traditional mode of risk stratification, Design Admission RBC fatty acid levels were measured in patients enrolled in a prospective, 24-center MI registry (TRIUMPH). Two-year mortality was modeled with Cox proportional hazards regression to assess the extent to which the inclusion of fatty acid levels would improve, over and above the GRACE score, risk stratification for 2-year mortality. Results RBC fatty acid data were available from 1,144 patients who did not report taking fish oil supplements after discharge. Two RBC fatty acids [eicosapentaenoic acid (EPA n-3) and docosapentaenoic n-6 (DPA)] were univariate predictors of total mortality. The combined fatty acid c-statistic (0.60, p<0.001) improved the c-statistic of the GRACE score alone from 0.747 (p<0.001) to 0.768 (p<0.05 vs. GRACE alone). The net reclassification index improved by 31% (95% CI, 15% to 48%) and the relative incremental discrimination index improved by 19.8% (7.5% to 35.7%). Conclusion RBC EPA and DPA n-6 levels improved the prediction of 2-yr mortality over and above the GRACE score in MI patients.

Red blood cell polyunsaturated fatty acids and mortality in the Women's Health Initiative Memory Study

“…In the present study, we found non-significant associations (p>0.01) with the Omega-3 Index and its major component, DHA, but a significant 12% reduction in CVD mortality per SD increase in EPA levels, and a 25% reduction for the PUFA factor score. This finding is consistent with a previous study in post-MI patients where RBC EPA, but not DHA, levels significantly improved prediction of 2-year mortality over a composite risk algorithm 12 . On the other hand, both EPA and DHA were associated with lower CVD mortality in another study of elderly individuals in the US 10 .…”

“…Among past studies that examined the relations between PUFA biomarkers and risk for death 4, 7–16 (Supplemental Table 1), most were conducted in Scandinavia, Europe or Taiwan, only three have been done in the US. In addition, only two 4, 12 utilized red blood cells (RBCs), and both were performed in patients with known coronary heart disease (CHD). Hence the question remains open whether RBC PUFA levels are associated with risk for all-cause and cause-specific death in the general US population.…”

Comparative effects of an acute dose of fish oil on omega-3 fatty acid levels in red blood cells versus plasma: Implications for clinical utility

“…1,22 This particular assay method has now been widely used in a variety of studies that examined not only CVD but also depression and cognitive function. [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] Others that used different analytical methods have reported RBC n-3 FA associations with other conditions. For example, in a large cohort in China, RBC DHA was strongly and inversely associated with risk of multiple forms of chronic disease.…”

Omega-3 Polyunsaturated Fatty Acids and Cardiovascular Health: A Comprehensive Review

“…The OMEGA-REMODEL trial suggested that the OM3 index may serve as a useful marker of treatment efficacy, 13 and it has also been shown that the Global Registry of Acute Coronary Events score had an improved c-statistic and correctly reclassified a significant proportion of patients by the inclusion of fatty acids. 14 We have previously argued that the inadmissibility of memory recall as scientific evidence limits the use of many nutritional studies, which may explain why the relation of OM3 in the diet to clinical events is looser than the association of measured blood levels of OM3 to clinical events. 12,15,16…”