Quality of care

Quality of care was evaluated based on 12 ESC guideline-recommended NSTEMI care interventions.⁷ These included: electrocardiogram (ECG) pre- or in-hospital, pre-hospitalization receipt of aspirin, echocardiography, invasive coronary angiography, medication at discharge to include aspirin, P2Y₁₂ inhibition, angiotensin converting ezyme inhibitor (ACEi)/angiotensin receptor blocker (ARB), beta-blocker and statin, referral to cardiac rehabilitation, smoking cessation advice, and dietary advice. The study period traversed two publications of ESC quality indicators for acute myocardial infarction, but the indicators we collected and analysed were consistent across both.^19,20 We included two additions lifestyle interventions—smoking cessation advice and dietary advice—because both are associated with a reduction in mortality and cardiovascular events,^21,22 and can be provided even in the absence of a full cardiac rehabilitation programme.

For each intervention, patients were considered ineligible if they were recorded as having a contra-indication or the data field recorded as not applicable. The all-or-none scoring composite performance measure was used as an aggregation method to define receipt of optimal care, i.e. patients who received all 12 of the care interventions for which they were eligible were considered to have received optimal care, but patients missing one or more interventions were considered to have received sub-optimal care.² If the data were missing, the patient was assumed not to have received the intervention. Overall, receipt of optimal care was split into four categories: no interventions received, <40% of eligible interventions received, ≥40%–<80% of eligible intervention received, and ≥80% of interventions received.²

To further distinguish patterns in care provision, guideline recommendations were also grouped as follows: pharmacological therapies (pre-hospitalization receipt of aspirin and prescription on discharge of each of aspirin, P2Y₁₂ inhibitor, ACEi/ARB, beta-blocker, and statin), investigative and invasive coronary strategies (electrocardiogram pre- or in-hospital, echocardiography, invasive coronary angiography) and lifestyle care interventions (referral to cardiac rehabilitation, smoking cessation advice, and dietary advice). This categorisation has been shown to offer higher resolution insights into the impact of care delivery on survival according to the GRACE risk score.⁵

Recorded outcomes included in-hospital episodes of acute heart failure, cardiogenic shock, use of mechanical circulatory support, bleed (BARC Type ≥ 3),²³ stroke/transient ischaemic attack, repeat myocardial infarction, and death from any cause, as well as 30 day-all-cause mortality.