Background: The impact of very low baseline levels of low-density lipoprotein cholesterol (LDL-C) on patients with coronary artery disease remains unclear.
Method: We enrolled 39,439 patients of the pooled population from the CREDO-Kyoto registries Cohorts 1, 2, and 3. The study population consisted of 33,133 patients who had undergone their first coronary revascularization. We assessed the risk for mortality and cardiovascular events according to quintiles of the baseline LDL-C levels.
Results: Patients in the very low LDL-C quintile (<85 mg/dL) had more comorbidities than those in the other quintiles. Lower LDL-C levels were strongly associated with anemia, thrombocytopenia, and end-stage renal disease. The cumulative 4-year incidence of all-cause death increased as LDL-C levels decreased (very low: 19.4 %, low: 14.5 %, intermediate: 11.1 %, high: 10.0 %, and very high: 9.2 %; p < 0.001), which was driven by both the early and late events. After adjusting for baseline characteristics, the adjusted risks of the very low and low LDL-C quintiles relative to the intermediate LDL-C quintile remained significant for all-cause death (very low: HR 1.29, 95 % CI 1.16-1.44, p < 0.001; low: HR 1.15, 95 % CI 1.03-1.29, p = 0.01). The excess adjusted risks of the lowest LDL-C quintile relative to the intermediate LDL-C quintile were significant for clinical outcomes such as cardiovascular death (HR 1.17, 95 % CI 1.01-1.35), non-cardiovascular death (HR 1.35, 95 % CI 1.15-1.60), sudden death (HR 1.44, 95 % CI 1.01-2.06), and heart failure admission (HR 1.11 95 % CI 1.01-1.22), while there was no excess risk for the lowest LDL-C quintile relative to the intermediate LDL-C quintile for myocardial infarction and stroke.
Conclusions: Lower baseline LDL-C levels were associated with more comorbidities and a significantly higher risk of death, regardless of cardiovascular or non-cardiovascular causes, in patients who underwent coronary revascularization.
Keywords: Coronary artery disease; Low-density lipoprotein cholesterol; Percutaneous coronary intervention.
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