Background: Use of invasive revascularization [percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG)] after acute myocardial infarction (AMI) in Denmark increased between 1996 and 2004. We investigated how this affected socioeconomic differences in their use.
Materials and methods: All patients aged 30-74 years in hospital for a first AMI in Denmark between 1996 and 2004 were included. Cox proportional hazard models were used to estimate the association between individual income (tertiles) and education (>12, 10-12 and <10 years) and time to revascularization within 6 months. Revascularization was stratified into CABG, acute PCI (within 2 days of admission) and non-acute PCI (after the third day).
Results: A total of 38,803 patients were included. In 1996-1998, 6.8% received CABG, 9.3% non-acute PCI and 2.4% acute PCI; in 2002-2004, these numbers were 11.8, 36.1 and 29.1%. CABG was more likely to be performed for patients with a high income [hazard ratio (HR), 1.18; 95% confidence interval (CI), 1.08-1.28] or a medium income (HR, 1.16; 95% CI, 1.07-1.25) than for those with a low income throughout the period. A similar income gradient was seen for non-acute PCI, but not for acute PCI, for which no gradient was seen. No educational gradient was found for CABG, and that for non-acute and acute PCI decreased during the period; by the end of the period, more patients with low than high education received acute PCI.
Conclusion: In the universal health care system of Denmark, income differences in CABG and non-acute PCI persisted, whereas no such differences were seen for acute PCI.