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Original Investigation
September 13, 2016

Association of Clinical Factors and Therapeutic Strategies With Improvements in Survival Following Non–ST-Elevation Myocardial Infarction, 2003-2013

Author Affiliations
  • 1Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, England
  • 2Department of Medicine, University of Toronto, Toronto, Ontario, Canada
  • 3Terrence Donnelly Heart Centre, St Michael’s Hospital, University of Toronto, Toronto, Ontario, Canada
  • 4Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
  • 5Instituto de investigación i+12 and Cardiology Department, Hospital Universitario 12 de Octubre, Madrid, Spain
  • 6Universidad Complutense de Madrid, Madrid, Spain
  • 7Department of Cardiovascular Medicine, Flinders University, Adelaide, Australia
  • 8Department of Cardiology, Concord Hospital, University of Sydney, Sydney, Australia
  • 9NIHR Cardiovascular Biomedical Research Unit, Barts Heart Centre, London, England
  • 10Pinderfields Hospital, Aberford Road, Wakefield, England
  • 11National Institute for Cardiovascular Outcomes Research, University College London, London, England
  • 12Farr Institute of Health Informatics Research, University College London, London, England
  • 13Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, Scotland
  • 14York Teaching Hospital NHS Foundation Trust, York, England
JAMA. 2016;316(10):1073-1082. doi:10.1001/jama.2016.10766

Importance  International studies report a decline in mortality following non–ST-elevation myocardial infarction (NSTEMI). Whether this is due to lower baseline risk or increased utilization of guideline-indicated treatments is unknown.

Objective  To determine whether changes in characteristics of patients with NSTEMI are associated with improvements in outcomes.

Design, Setting, and Participants  Data on patients with NSTEMI in 247 hospitals in England and Wales were obtained from the Myocardial Ischaemia National Audit Project between January 1, 2003, and June 30, 2013 (final follow-up, December 31, 2013).

Exposures  Baseline demographics, clinical risk (GRACE risk score), and pharmacological and invasive coronary treatments.

Main Outcomes and Measures  Adjusted all-cause 180-day postdischarge mortality time trends estimated using flexible parametric survival modeling.

Results  Among 389 057 patients with NSTEMI (median age, 72.7 years [IQR, 61.7-81.2 years]; 63.1% men), there were 113 586 deaths (29.2%). From 2003-2004 to 2012-2013, proportions with intermediate to high GRACE risk decreased (87.2% vs 82.0%); proportions with lowest risk increased (4.2% vs 7.6%; P= .01 for trend). The prevalence of diabetes, hypertension, cerebrovascular disease, chronic obstructive pulmonary disease, chronic renal failure, previous invasive coronary strategy, and current or ex-smoking status increased (all P < .001). Unadjusted all-cause mortality rates at 180 days decreased from 10.8% to 7.6% (unadjusted hazard ratio [HR], 0.968 [95% CI, 0.966-0.971]; difference in absolute mortality rate per 100 patients [AMR/100], −1.81 [95% CI, −1.95 to −1.67]). These findings were not substantially changed when adjusted additively by baseline GRACE risk score (HR, 0.975 [95% CI, 0.972-0.977]; AMR/100, −0.18 [95% CI, −0.21 to −0.16]), sex and socioeconomic status (HR, 0.975 [95% CI, 0.973-0.978]; difference in AMR/100, −0.24 [95% CI, −0.27 to −0.21]), comorbidities (HR, 0.973 [95% CI, 0.970-0.976]; difference in AMR/100, −0.44 [95% CI, −0.49 to −0.39]), and pharmacological therapies (HR, 0.972 [95% CI, 0.964-0.980]; difference in AMR/100, −0.53 [95% CI, −0.70 to −0.36]). However, the direction of association was reversed after further adjustment for use of an invasive coronary strategy (HR, 1.02 [95% CI, 1.01-1.03]; difference in AMR/100, 0.59 [95% CI, 0.33-0.86]), which was associated with a relative decrease in mortality of 46.1% (95% CI, 38.9%-52.0%).

Conclusions and Relevance  Among patients hospitalized with NSTEMI in England and Wales, improvements in all-cause mortality were observed between 2003 and 2013. This was significantly associated with use of an invasive coronary strategy and not entirely related to a decline in baseline clinical risk or increased use of pharmacological therapies.