Omega-3 index and prognosis in acute coronary chest pain patients with a low dietary intake of omega-3

Abstract

Background. The omega-3 index (eicosapentaenoic acid + docosahexaenoic acid) content in red blood cell membranes has been suggested as a novel risk marker for cardiac death. Objective. To assess the ability of the omega-3 index to predict all-cause mortality, cardiac death and sudden cardiac death following hospitalization with an acute coronary syndrome (ACS), and to include arachidonic acid (AA) in risk assessment. Material and methods. The omega-3 index was measured in 572 consecutive patients (median 63 years and 59% males) admitted with chest pain and suspected ACS in an inland Northern Argentinean city with a dietary habit that was essentially based on red meat and a low intake of fish. Clinical endpoints were collected during a 5-year follow-up period, median 3.6 years, range 1 day to 5.5 years. Stepwise Cox regression analysis was employed to compare the rate of new events in the quartiles of the omega-3 index measured at inclusion. Multivariable analysis was performed. Results. No statistical significant differences in baseline characteristics were noted between quartiles of the omega-3 index. The median of the adjusted omega-3 index was 3.6%. During the follow-up period, 100 (17.5%) patients died. Event rates were similar in all quartiles of the omega-3 index, with no statistical significant differences. AA added no prognostic information. Conclusion. In a population with a low intake of fish and fish oils, the adjusted omega-3 index did not predict fatal events following hospitalization in patients with acute chest pain and suspected ACS.

Key words::

• acute coronary syndrome
• mortality
• omega-3 fatty acids

Acknowledgments

We gratefully acknowledge the contribution by the participating medical doctors: Alejandro Farah (Hospital San Bernardo), Sebastian Saravia Toledo (CENESA), Sebastian Araujo (Hospital Privado Santa Clara de Asis), Pedro Kairuz (Hospital Militar), Fernando Marconetto (Sanatorio San Roque), Cesar Laspiur (Clinica San Rafael), Patricio Gallo (Sanatorio El Carmen), Fernando Rassi (Sanatorio Parque), Florencia Wayar (Clinica Guemes) and the service rendered by our devoted biochemical engineers Silvia Dib Ashur, Carolina Moreno Ten, Natalia Ruiz and Mariela Ponce. Furthermore, we appreciate the support of Professor Augusto Torino at the Favaloro Institute. Also, we wish to extend our gratitude to Ernesto Lovaglio MD, Maria José Aleman, and Valeria Choque for their coordinating service. We are also grateful for the facilities we used at the Catholic University of Salta.

In the non-Argentinean part of the study, we greatly value the contribution by our statistician Harry Staines PhD and by Heidi Grundt MD PhD who coordinated the database. Also, we highly appreciate the analytical work on the fatty acid analyses provided by Tore Bolstad.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.