Association between baseline LDL-C and prognosis among patients with coronary artery disease and advanced kidney disease

BACKGROUND: Lower low-density lipoprotein cholesterol (LDL-C) is significantly associated with improved prognosis in patients with coronary artery disease (CAD). However, LDL-C reduction does not decrease all-cause mortality among CAD patients when renal function impairs. The association between low baseline LDL-C (< 1.8 mmol/L) and mortality is unknown among patients with CAD and advanced kidney disease (AKD). The current study aimed to evaluate prognostic value of low baseline LDL-C level for all-cause death in these patients. METHODS: In this observational study, 803 CAD patients complicated with AKD (eGFR < 30 mL/min/1.73 m(2)) were enrolled between January 2008 to December 2018. Patients were divided into two groups (LDL-C < 1.8 mmol/L, n = 138; LDL-C ≥ 1.8 mmol/L, n = 665). We used Kaplan-Meier methods and Cox regression analyses to assess the association between baseline low LDL-C levels and long-term all-cause mortality. RESULTS: Among 803 participants (mean age 67.4 years; 68.5% male), there were 315 incidents of all-cause death during a median follow-up of 2.7 years. Kaplan–Meier analysis showed that low LDL-C levels were associated with worse prognosis. After adjusting for full 24 confounders (e.g., age, diabetes, heart failure, and dialysis, etc.), multivariate Cox regression analysis revealed that lower LDL-C level (< 1.8 mmol/L) was significantly associated with higher risk of all-cause death (adjusted HR, 1.38; 95% CI, 1.01–1.89). CONCLUSIONS: Our data demonstrated that among patients with CAD and AKD, a lower baseline LDL-C level (< 1.8 mmol/L) did not present a higher survival rate but was related to a worse prognosis, suggesting a cautiousness of too low LDL-C levels among patients with CAD and AKD. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12882-021-02375-1.