Trends of relative and absolute socioeconomic equity in access to coronary revascularisations in 1995–2010 in Finland: a register study

BACKGROUND Resources for coronary revascularisations have increased substantially since the early 1990s in Finland. At the same time, ischaemic heart disease (IHD) mortality has decreased markedly. This study aims to examine how these changes have influenced trends in absolute and relative differences between socioeconomic groups in revascularisations and age group differences in them using IHD mortality as a proxy for need. METHODS Hospital Discharge Register data on revascularisations among Finns aged 45-84 in 1995-2010 were individually linked to population registers to obtain socio-demographic data. We measured absolute and relative income group differences in revascularisation and IHD mortality with slope index of inequality (SII) and concentration index (C), and relative equity taking need for care into account with horizontal inequity index (HII). RESULTS The supply of procedures doubled during the years. Socioeconomic distribution of revascularisations was in absolute and relative terms equal in 1995 (Men: SII = -12, C = -0.00; Women, SII = -30, C = -0.03), but differences favouring low-income groups emerged by 2010 (M: SII = -340, C = -0.08; W: SII = -195, C = -0.14). IHD mortality decreased markedly, but absolute and relative differences favouring the better-off existed throughout study years. Absolute differences decreased somewhat (M: SII = -760 in 1995, SII = -681 in 2010; W: SII = -318 in 1995, SII = -211 in 2010), but relative differences increased significantly (M: C = -0.14 in 1995, C = -0.26 in 2010; W: C = -0.15 in 1995, C = -0.25 in 2010). HII was greater than zero in each year indicating inequity favouring the better-off. HII increased from 0.15 to 0.18 among men and from 0.10 to 0.12 among women. We found significant and increasing age group differences in HII. CONCLUSIONS Despite large increase in supply of revascularisations and decrease in IHD mortality, there is still marked socioeconomic inequity in revascularisations in Finland. However, since changes in absolute distributions of both supply and need for coronary care have favoured low-income groups, absolute inequity can be claimed to have decreased although it cannot be quantified numerically.