Association Between Total Cholesterol and In-Hospital Mortality Among First-Episode Acute Coronary Syndrome Patients: Multilevel Analysis from NCVD-ACS Registry

Background: Cardiovascular disease (CVD) remains the leading cause of mortality worldwide, particularly in low- and middle-income countries. Although elevated cholesterol is a well-established modifiable risk factor for atherosclerotic CVD, the phenomenon known as the “cholesterol paradox” has raised uncertainty regarding the prognostic significance of admission cholesterol levels in patients with acute coronary syndrome (ACS). Therefore, this study aimed to evaluate the association between admission total cholesterol (TC) levels and in-hospital mortality among patients with first-episode ACS. Methods: Data were obtained from the National Cardiovascular Disease Database-Acute Coronary Syndrome (NCVD-ACS) registry, where this cross-sectional study implemented a consecutive sampling of the nationwide ACS patient database for eligible records from January 2006 to December 2015. The patients were then classified into quartiles according to their TC levels, with the corresponding all-cause in-hospital mortality considered the outcome. Following adjustments for potential confounding factors, multilevel analysis ensued to determine the association between cholesterol groups and mortality. Results: The quartile two (Q2) group (4.50–5.36 mmol/L) was employed as the reference for this study. From the 16,860 ACS cases (mean age = 54.1 years; 83.9% male) analysed, which included 648 in-hospital fatalities, lower cholesterol levels were linked to higher mortality rates, except among patients with unstable angina. Interestingly, patients with non-ST-segment elevation myocardial infarction (NSTEMI) demonstrated a U-shaped trend. The results also revealed adjusted odds ratio (OR) for mortality (95% CI: 1.15–4.03) for Q1 at 2.15 (2.00–4.49 mmol/L), 2.01 (95% CI: 1.01–3.98) for Q3 (5.37–6.25 mmol/L), and 2.15 (95% CI: 1.08–4.26) for Q4 (>6.25 mmol/L), suggesting an increased mortality among patients with low and high cholesterol levels. Conclusions: Among first-episode ACS patients, both low and high cholesterol levels were associated with increased in-hospital mortality. A significant U-shaped relationship was observed among NSTEMI patients.