Markers of inflammation predicts long-term mortality in patients with acute coronary syndrome – a longitudinal cohort study

Background: A chronic low-grade inflammation is a well-known risk factor for the development of coronary heart disease (CHD) and future cardiovascular events, and anti-inflammatory therapy can reduce the risk of ischemic cardiovascular disease (CVD) events following a myocardial infarction. It is not known to what extent inflammation at time of an acute event is predictive of long-term events. We explored the hypothesis that routine blood measurements of markers of inflammation in an acute coronary syndrome (ACS) are predictive of future long-term mortality. Methods: In a cohort of 5292 consecutive patients admitted to a coronary intensive care unit with suspected ACS over a four-year period in the Carlscrona Heart Attack Prognosis Study (CHAPS), 908 patients aged 30-74 years (644 men, 264 women) had at discharge received the diagnosis of either myocardial infarction (MI) (527) or unstable angina (UA) (381). In this group we performed a longitudinal 10-year follow-up study based on information from the Swedish national registries, using total mortality and cardiac disease mortality as primary outcome measures. Results: Long term total mortality and cardiac mortality was significantly associated with higher leucocyte counts (e.g. neutrophiles, monocytes, eosinophiles) and higher levels of inflammatory biomarkers (e.g. C-reactive protein, Serum Amyloid A (SAA), fibrinogen, neutrophile-lymphocyte ratio (NLR) and monocyte-lymphocyte ratio (MLR)), measured at time of hospital admission for ACS. These findings were independent of the ACS diagnosis. Conclusion: Our results suggests that degree of inflammation at time of ACS presentation, beyond its established role as major risk factor for development of CHD, has further role in long-term mortality following an ACS. Interestingly, our results suggest that the inflammation at time of the event is a stronger predictor of long term mortality than the outcome of the acute event.