Are there socioeconomic differences in outcomes of coronary revascularizations--a register-based cohort study

Earlier studies have reported socioeconomic differences in coronary heart disease incidence and mortality and in coronary treatment, but less is known about outcomes of care. We examined trends in income group differences in outcomes of coronary revascularizations among Finnish residents in 1998-2010. First revascularizations for 45-84-year-old Finns were extracted from the Hospital Discharge Register in 1998-2009 and followed until 31 December 2010. Income was individually linked to them and adjusted for family size. We examined the risk of major adverse cardiac events (MACEs), coronary mortality and re-revascularization. We calculated age-standardized rates with direct method and Cox regression models. Altogether 69 076 men and 27 498 women underwent revascularization during the study period. Among men [women] in the 1998 cohort, 41% [35%] suffered MACE during 29 days after the operation and 30% [28%] in the 2009 cohort. Myocardial infarction mortality within 1 year was 2% among both genders in both cohorts. Among men [women] 9% [14%] underwent revascularization within 1 year after the operation in 1998 and 12% [12%] in 2009. Controlling for age, co-morbidities, year, previous infarction and disease severity, an inverse income gradient was found in MACE incidence within 29 days and in coronary mortality. The excess MACE risk was 1.39 and excess mortality risk over 1.70 among both genders in the lowest income quintile. All income group differences remained stable from 1998 to 2010. In health care, more attention should be paid to prevention of adverse outcomes among persons with low socioeconomic position undergoing revascularization.