Temporal Trends in Diagnosis, Treatment, and Outcome for Non-ST-Segment Elevation Acute Coronary Syndrome in Three Regions of China, 2008–2015
Acute coronary syndromes (ACS) are a leading cause of morbidity and mortality in China, making them a critical area of study to evaluate the impact of healthcare reforms on the quality, safety, and efficiency of medical care. ACS encompasses a spectrum of conditions, including ST-segment elevation myocardial infarction (STEMI), unstable angina (UA), and non-ST-segment elevation myocardial infarction (NSTEMI). Non-ST-segment elevation acute coronary syndrome (NSTE-ACS), which includes NSTEMI and UA, accounts for approximately two-thirds of ACS cases. Given the wide range of disease severity in NSTE-ACS patients, risk-stratified management is essential to ensure appropriate resource allocation, particularly in resource-limited settings like China.
This study aimed to analyze temporal trends in the diagnosis, treatment, and outcomes of hospitalized NSTE-ACS patients in three regions of China—Beijing, Henan, and Jilin—between 2008 and 2015. The study was conducted through a retrospective review of medical records from 38 hospitals (24 tertiary and 14 secondary) in these regions. The inclusion criteria were adult patients (age ≥18 years) with a primary discharge diagnosis of NSTEMI or UA. Patients who died within 10 minutes of hospital arrival, self-discharged, were transferred from another hospital, or were non-permanent residents of the local region were excluded. The study received ethics approval from the local Institutional Review Boards, with a waiver of informed consent due to the retrospective chart review design.
The study evaluated in-hospital clinical outcomes, including major adverse cardiovascular events (MACE), which comprised all-cause death, recurrent nonfatal myocardial infarction (MI), non-fatal stroke, heart failure (HF), and major bleeding. MI and stroke were defined based on the diagnosis documented by the treating physician. HF included episodes of acute pulmonary edema, cardiogenic shock, or clinical diagnosis at discharge. Major bleeding was defined as a decline in hemoglobin by 2 g/dL or more, the need for blood transfusion, medical or surgical intervention, or permanent physical dysfunction due to intracranial hemorrhage.
Temporal trends in diagnostic testing, treatment, and MACE were assessed using a generalized linear mixed-effect model (GLMM). The model adjusted for patient-level and hospital-level characteristics, including admission year, age, sex, insurance status, hospital level, history of percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) surgery, history of diabetes mellitus, systolic blood pressure (SBP 100 bpm), and estimated glomerular filtration rate (eGFR 140) and low-to-intermediate risk (GRACE score ≤140) groups. Differences between these risk groups were tested using an interaction term between admission year and GRACE group.
The study included 13,759 NSTE-ACS patients from 14,729 admissions between 2008 and 2015. Over the study period, the proportion of patients diagnosed with NSTEMI increased from 14% in 2008 to 19% in 2015. This increase was accompanied by rising socioeconomic status and a higher prevalence of comorbidities, including a history of MI, PCI or CABG, diabetes mellitus, stroke or transient ischemic attack, and dyslipidemia. Conversely, the proportion of patients with kidney dysfunction (eGFR < 60 mL/min/1.73 m²) decreased from 7.2% in 2008 to 5.5% in 2015.
Diagnostic testing trends showed an increase in troponin testing (42.8% to 77.6%) and a decrease in creatine kinase-myocardial band (CK-MB) testing (66.7% to 75.6%) over the study period. The utilization of coronary angiography and coronary computed tomographic angiography (CCTA) also increased, from 34.8% to 52.5% and from 5.2% to 8.2%, respectively. However, stress testing remained very low, particularly in low-to-intermediate risk patients (4.5% to 2.4%).
Treatment trends indicated an increase in the use of dual antiplatelet therapy (56.4% to 76.9%), glycoprotein IIb/IIIa inhibitors (3.0% to 8.3%), and statins (73.4% to 92.7%). Although the rate of PCI increased from 21.2% to 26.2%, the likelihood of a patient receiving PCI did not change significantly after adjustment for patient and hospital characteristics. The use of angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) decreased from 60.3% in 2008 to 50.8% in 2015, while beta-blocker use remained stable at around 68%.
High-risk patients were more likely to receive dual antiplatelet therapy and glycoprotein IIb/IIIa inhibitors but less likely to undergo PCI compared to low-to-intermediate risk patients. The use of statins, ACEIs/ARBs, and beta-blockers was similar in both risk groups. The likelihood of undergoing PCI did not change significantly in either risk group over the study period.
The overall MACE rate remained stable, ranging from 3% in 2008 to 3.7% in 2015. However, when stratified by risk, the MACE rate decreased from 13.4% in 2008 to 9.5% in 2015 in high-risk patients, while it increased slightly from 1.6% to 2.7% in low-to-intermediate risk patients. The adjusted MACE rate decreased significantly over the study period, driven primarily by a reduction in in-hospital HF among high-risk patients, which declined from 9.1% in 2008 to 5.4% in 2015.
This study highlights significant increases in medical resource consumption for NSTE-ACS patients in China between 2008 and 2015. Despite improvements in diagnostic testing and treatment, there remains considerable room for optimization in the management of NSTE-ACS, particularly in the use of evidence-based therapies such as antiplatelets, statins, beta-blockers, and ACEIs/ARBs. The findings underscore the need for further implementation of evidence-based practices, monitoring of acute cardiovascular care quality, and the reduction of unnecessary or inappropriate treatments to improve the efficiency of China’s healthcare system.
doi.org/10.1097/CM9.0000000000001664
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