Low-density lipoprotein cholesterol of less than 70 mg/dL is associated with fewer cardiovascular events in acute coronary syndrome patients: a real-life cohort in Thailand

Abstract

Dujrudee Chinwong,1,2 Jayanton Patumanond,3 Surarong Chinwong,1 Khanchai Siriwattana,4 Siriluck Gunaparn,5 John Joseph Hall,6 Arintaya Phrommintikul5 1Department of Pharmaceutical Care, Faculty of Pharmacy, Chiang Mai University, Chiang Mai, Thailand; 2Clinical Epidemiology Program, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand; 3Center of Excellence in Applied Epidemiology, Faculty of Medicine, Thammasat University, Pathum Thani, Thailand; 4Division of Medicine, Nakornping Hospital, Chiang Mai, Thailand; 5Department of Internal Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand; 6Centre for Clinical Epidemiology and Biostatistics, School of Medicine and Public Health, Faculty of Health, University of Newcastle, Callaghan, NSW, Australia Background: Elevated low-density lipoprotein cholesterol (LDL-C) is associated with an increased risk of cardiovascular disease or mortality; however, the LDL-C goal for therapy in acute coronary syndrome (ACS) patients is controversial and varies among guidelines. This study aimed to assess the effect of reaching an LDL-C goal of <70 mg/dL (<1.8 mmol/L) on first composite cardiovascular outcomes in routine clinical practice in Thailand.Methods: A retrospective cohort study was conducted using medical charts and the electronic hospital database of patients diagnosed with ACS and treated with statins at a tertiary care hospital in Thailand between 2009 and 2012. After admission, patients were followed from the date of LDL-C goal assessment until the first event of composite cardiovascular outcomes (nonfatal ACS, nonfatal stroke, or all-cause death). Cox proportional hazard models adjusted for potential confounders were used.Results: Of 405 patients, mean age was 65 years (60% males). Twenty-seven percent of the patients attained an LDL-C goal of <70 mg/dL, 38% had LDL-C between 70 and 99 mg/dL, and 35% had LDL-C ≥100 mg/dL. Forty-six patients experienced a composite cardiovascular outcome. Compared with patients with an LDL-C ≥100 mg/dL, patients achieving an LDL-C of <70 mg/dL were associated with a reduced composite cardiovascular outcome (adjusted hazard ratio [HR]=0.42; 95% confidence interval [CI]=0.18–0.95; P-value=0.037), but patients with an LDL-C between 70 and 99 mg/dL had a lower composite cardiovascular outcome, which was not statistically significant (adjusted HR=0.73; 95% CI=0.37–1.42; P-value=0.354).Conclusion: ACS patients who received statins and achieved an LDL-C of <70 mg/dL had significantly fewer composite cardiovascular outcomes, confirming “the lower the better” and the benefit of treating to LDL-C target in ACS patient management. Keywords: LDL-C goal attainment, achieving LDL-C goal, statins, acute coronary syndrome, composite cardiovascular events