Abstract WP150: Joint association of low-density lipoprotein cholesterol and systolic blood pressure with hemorrhagic stroke death: a nationwide prospective cohort study

Introduction: Lowering elevated low-density lipoprotein cholesterol (LDL-C) is the key strategy for prevention of atherosclerotic cardiovascular disease. However, increasing evidences have implied the possible intracerebral hemorrhagic risk resulted from very low levels of LDL-C. It is thus of clinical significance to understand the factors related to the risk of hemorrhagic stroke in the individuals with low levels of LDL-C. Elevated blood pressure (BP), particularly systolic BP (SBP), was identified as the main risk factors contributing hemorrhagic stroke. Data linking SBP and LDL-C with cardiovascular diseases showed a synergistic association. However, comprehensive understanding on the combined effects of LDL-C and SBP on the risk of hemorrhagic stroke events is lacking. The objective of this study therefore was to systematically examine the joint association of LDL-C and SBP with hemorrhagic stroke death among the whole population and population subgroups. Methods: We performed a prospective cohort study among 3,449,305 participants enrolled in the ChinaHEART project with measured LDL-C. Hemorrhagic stroke death data was ascertained from the National Mortality Surveillance System and Vital Registration. We used Fine&Gray model to analyze the joint association. Results: During the 4-year follow-up, 7,173 participants (0.21%) died due to hemorrhagic stroke. Participants with LDL-C <70 mg/dL and SBP ≥120 mmHg had higher risks of hemorrhagic stroke death than those with LDL-C ≥70 mg/dL and SBP of 120–140 mmHg; hazard ratios (HRs) were 1.36 (1.24–1.50) for LDL-C <70 mg/dL and 120 mmHg ≤SBP <140 mmHg, and 2.53 (2.34–2.74) for LDL-C <70 mg/dL and SBP ≥140 mmHg, whereas the risk was not pronounced among individuals with LDL-C <70 mg/dL and SBP <120 mmHg [HR=0.93 (0.79–1.09)]. Stratified analyses showed lower LDL-C levels were associated with a higher risk of hemorrhagic stroke death, whereas the inverse association was confined to participants without lipid-lowering treatment. Conclusions: Considerable excess risk of hemorrhagic stroke death was observed in participants with LDL-C <70 mg/dL and SBP ≥120 mmHg, particularly among those with SBP ≥140 mmHg, whereas the association became nonsignificant among individuals with SBP <120 mmHg. Lower levels of LDL-C were associated with a higher risk of hemorrhagic stroke death confined to participants without lipid-lowering treatment, which need more studies to further validate.