Association between remnant cholesterol levels and the in-hospital outcomes and long-term prognosis in ST-segment elevated myocardial infarction patients

Background Remnant cholesterol is emerging as residual lipid risk factors of coronary heart diseases supported by substantial evidence. Nevertheless, studies on the association between remnant cholesterol levels and prognosis in patients with STEMI are insufficient, and they were conducted in small sample size. Purpose The objective of this study was to investigate the relationship between remnant cholesterol levels and the risk of in-hospital and long-term mortality in STEMI patients in a large prospective cohort, the CAMI registry. Methods In this study, patients with STEMI enrolled from the CAMI registry were categorised by the quartile of remnant cholesterol distribution. remnant cholesterol was calculated by the equation: total cholesterol minus LDL cholesterol minus HDL cholesterol. The primary endpoints were in-hospital mortality and 24 months all-cause mortality. Cox-regression models were used to estimate the association between remnant cholesterol and risk of mortality. Results A total of 14928 patients with STEMI were included in the main analysis and divided by the inter-quartile of remnant cholesterol. The lower quartile, median and upper quartile of remnant cholesterol were 0.42mmol/L, 0.64mmol/L and 0.94mmol/L, respectively. We observed a U-shaped association between remnant cholesterol levels and in-hospital and long-term mortality. The in-hospital mortality was 5.8% in lowest quartile, 4.1% in the second quartile, 4.3% in the third quartile and 4.5% in the highest quartile(P=0.0020). After multivariable adjustment, the decrease in in-hospital mortality was still observed in the second quartile[HR (95%CI): 0.764 (0.620-0.942), P=0.0118]. In the 24-month follow-up, the all-cause mortality rate was 13.0% in the first quartile, 10.5% in the second quartile, 10.2% in the third quartile and 10.4% the fourth quartile (P=0.0003). After multivariable adjustment, we found a lower risk in the second and the third quartile[Q2: HR (95%CI): 0.835 (0.727-0.958),P=0.0103;Q3: HR (95%CI): 0.858 (0.747-0.987), P=0.0319]. Conclusions The analysis of STEMI patients demonstrates that both very low and elevated remnant cholesterol levels were associated with higher risk of in-hospital mortality and long-term mortality. A better prognosis was observed in the second and third quartiles of remnant cholesterol, ranging from 0.42mmol/L to 0.94mmol/L. Comprehensive assessment of the lipid profile, including remnant cholesterol, may play a relevant role in the primary and secondary prevention of cardiovascular disease. Enhanced lifestyle management alongside developed lipid-lowering therapy is highly underscored in the STEMI patients to improve prognosis.