Patients’ characteristics
This study included 92509 ACS patients from 240 hospitals across China. The clinical characteristics of these patients are summarized in Table 1. The average age of these ACS patients was 63 years, and 73.9% of them were men.
The percentages of patients with eGFR≥90 ml/min·1.73m2, 60-89 ml/min·1.73m2, 45-59 ml/min 1.73 m2, 30-44 ml/min 1.73 m2 and < 30 ml/min 1.73 m2 were 45.95%, 36.17%, 9.06%, 5.38% and 3.43%, respectively. The comparison results were shown in Table 1. With the decrease of eGFR, the proportion of STEMI decreased gradually, while the proportion of NSTE-ACS increased gradually. The proportion of patients with hypertension, diabetes mellitus, heart failure, previous heart myocardial and previous stroke increased gradually, while the proportion of patients with hyperlipidemia and LDL-C level decreased gradually. With the decrease of eGFR, the proportion of patients with taking β-blockers, antiplatelet drugs and statins before admission increased, while the proportion of patients with taking ACEI/ARB decreased when the eGFR<60 ml/min·1.73m2. With the decrease of eGFR, the proportion of patients undergoing coronary angiography and PCI decreased significantly after admission, while the severity of coronary artery lesions in patients undergoing angiography increased gradually.
Compared to the patients with STEMI, patients with NSTE-ACS had a higher proportion of RI: the percentages of patients with 60-89 ml/min·1.73m2,45-59 ml/min 1.73 m2, 30-44 ml/min 1.73 m2 and < 30 ml/min 1.73 m2 in STEMI patients were 34.95%, 8.65%, 4.89% and 2.73%, respectively, while those in NSTE-ACS patients were 38.00%, 9.68%, 6.26% and 4.49%, respectively. (Figure 1) Compared to the patients with STEMI, the proportion of previous MI, hypertension, diabetes, previous stroke, previous PCI or CABG, use of β-blocker and ACEI/ARB before admission were increased in patients with NSTE-ACS.(Additional file1: Table S1)
In-hospital outcomes
The proportion of in-hospital mortality was 1.7%, heart failure in hospital was 8.0%, cardiogenic shock in hospital was 2.6%, and cardiac arrest in hospital was 1.6% in all the ACS patients. Moreover, the proportion of MACEs were 7.0%, 13.6%, 25.1%, 35.4%, and 46.7% in patients with eGFR ≥ 90ml/min·1.73m2, 60-89 ml/min·1.73m2, 45-59 ml/min 1.73 m2, 30-44 ml/min 1.73 m2 and < 30 ml/min 1.73 m2 respectively. With the decrease of eGFR, the proportion of in-hospital mortality, heart failure, cardiac arrest and cardiogenic shock increased gradually. (Figure 2).
Compared to the patients with STEMI, patients with NSTE-ACS had a higher proportion of all-cause death, cardiac arrest, cardiogenic shock, heart failure were decreased.(Additional file1: Table S2)
Relationship between eGFR and MACE
To evaluate the association between eGFR and MACE, logistic regression analyses were performed in the ACS population. In univariate logistic regression analysis, a significantly higher risk of the MACEs was observed in patients with RI. After adjusting for confounders in the multivariate logistic regression model, patients with eGFR 60-89 ml/min·1.73m2, 45-59 ml/min·1.73m2, 30-44 ml/min·1.73m2 and <30 ml/min·1.73m2 had a 1.3-fold(OR, 1.27; 95% CI, 1.19-1.35), 1.7-fold(OR, 1.65; 95% CI, 1.52-1.80), 2.0-fold(OR, 2.04; 95% CI, 1.85-2.26) and 2.2-fold(OR, 2.23, 95% CI, 1.98-2.50) increased risk of MACEs compared to patients with eGFR ≥90 ml/min·1.73m2. (Table 2)
In order to explore the relationship between eGFR and MACE in different types of ACS, subgroup analysis was performed based on STEMI and NST-ACS population respectively. In the patients with STEMI, after adjusted for confounders in the multivariate logistic regression model, patients with eGFR 60-89 ml/min·1.73m2, 45-59 ml/min·1.73m2, 30-44 ml/min·1.73m2 and <30 ml/min·1.73m2 had a 1.2-fold(OR, 1.25; 95% CI, 1.16-1.34), 1.6-fold(OR, 1.56; 95% CI, 1.40-1.73), 1.9-fold(OR, 1.92; 95% CI, 1.70-2.17) and 2.4-fold(OR, 2.38, 95% CI, 2.05-2.76) increased risk of MACEs compared to patients with eGFR ≥90 ml/min·1.73m2. (Table 3) In the patients with NST-ACS, after adjusting for confounders in the multivariate logistic regression model, patients with eGFR 60-89 ml/min·1.73m2, 45-59 ml/min·1.73m2, 30-44 ml/min·1.73m2 and <30 ml/min·1.73m2 had a 1.4-fold(OR, 1.41; 95% CI, 1.25-1.59), 2.0-fold(OR, 12.01; 95% CI, 1.72-2.34), 2.6-fold(OR, 2.57; 95% CI, 2.18-3.04) and 2.7-fold(OR, 2.69, 95% CI, 2.23-3.24) increased risk of MACEs compared to patients with eGFR ≥90 ml/min·1.73m2. (Table 3)
The attributable risk of eGFR for MACE
In all the ACS patients, the attributable risk of eGFR 60-89 ml/min·1.73m2 was 8.96%, 5.59% of eGFR 45-59 ml/min·1.73m2, 5.31% of eGFR 30-44 ml/min·1.73m2, and 4.03% of eGFR<30 ml/min·1.73m2. (Table 2)
According to the results of regression analysis, we calculated the attributable risk of MACE in STEMI and NST-ACS population with different eGFR stratification. In the patients with STEMI, the attributable risk of eGFR 60-89 ml/min·1.73m2 was 8.00%, 4.59% of eGFR 45-59 ml/min·1.73m2, 4.22% of eGFR 30-44 ml/min·1.73m2, and 3.63% of eGFR<30 ml/min·1.73m2. In the patients with NSTE-ACS, the attributable risk of eGFR 60-89 ml/min·1.73m2 for MACE was 15.50%, 9.73% of eGFR 45-59 ml/min·1.73m2, 9.84% of eGFR 30-44 ml/min·1.73m2, and 7.58% of eGFR<30 ml/min·1.73m2.(Table 3)