Are non-ST-segment elevation myocardial infarctions missing in China?

Abstract

Aims: ST-segment elevation myocardial infarctions (STEMI) in China and other low- and middle-income countries outnumber non-ST-segment elevation myocardial infarctions (NSTEMI). We hypothesized that the STEMI predominance was associated with lower biomarker use and would vary with hospital characteristics.

Methods and results: We hypothesized that the STEMI predominance was associated with lower biomarker use and would vary with hospital characteristics. Using data from the nationally representative China PEACE-Retrospective AMI Study during 2001, 2006, and 2011, we compared hospital NSTEMI proportion across categories of use of any cardiac biomarker (CK, CK-MB, or troponin) and troponin, as well as across region, location, level, and teaching status. Among 15 416 acute myocardial infarction (AMI) patients, 14% had NSTEMI. NSTEMI patients were older, more likely female, and to have comorbidities. Median hospital NSTEMI proportion in each study year was similar across categories of any cardiac biomarker use, troponin, region, location, level, and teaching status. For instance, in 2011 the NSTEMI proportion at hospitals without troponin testing was 11.2% [inter quartile range (IQR) 4.4-16.7%], similar to those with ≥ 75% troponin use (13.0% [IQR 8.7-23.7%]) (P-value for difference 0.77). Analysed as continuous variables there was no relationship between hospital NSTEMI proportion and proportion biomarker use. With troponin use there was no relationship in 2001 and 2006, but a modest correlation in 2011 (R = 0.16, P = 0.043). Admissions for NSTEMI increased from 0.3/100 000 people in 2001 to 3.3/100 000 people in 2011 (P-value for trend < 0.001).

Conclusion: STEMI is the dominant presentation of AMI in China, but the proportion of NSTEMI is increasing. Biomarker use and hospital characteristics did not account for the low NSTEMI rate.

Clinical trial registration: www.clinicaltrials.gov (NCT01624883).

Keywords: Acute myocardial infarction; Low- and middle-income countries; ST-segment elevation myocardial infarction.