Disentangling the Inverse LDL-C-hemorrhagic Stroke Association in Chinese Adults with Hypertension: Findings from the Chinese Multi-Provincial Cohort Study.

Why lower low-density lipoprotein cholesterol (LDL-C) was associated with a decreased atherosclerotic cardiovascular disease (ASCVD) risk but an increased hemorrhagic stroke (HS) risk in hypertensive adults remains unclear. We examined whether the inverse LDL-C-HS association partly arises from its effect on ASCVD. We estimated separable effects of LDL-C on HS outside (i.e., separable direct effect) or only through its effect on ASCVD (i.e., separable indirect effect) in hypertensive adults from the Chinese Multi-provincial Cohort Study. We quantified such effects using numbers needed to treat (NNT) to prevent or cause an extra HS based on the restricted mean event-free time till a 25-year follow-up. LDL-C $<$ 70 mg/dL was not associated with an increased HS risk compared to LDL-C $\ge$ 70 mg/dL regarding total and separable direct effects. However, a small separable indirect effect (i.e., NNT to harm: 9722 participants) was noted and validated via a series of sensitivity analyses. Moreover, modified effects were observed, particularly in the 35-49-year age group, men, and those with SBP $\ge$ 140 mm Hg. These results suggest the inverse LDL-C-HS association in hypertensive adults is partly due to its effect on ASCVD. A better understanding of such associations would provide more enlightening into stroke prevention.