Income inequalities in case death of ischaemic heart disease in the Netherlands: a national record-linked study

Abstract

Background: Socioeconomic inequalities in ischaemic heart disease (IHD) mortality have been found in most European countries, but it is unclear to what extent inequalities in survival, as opposed to incidence, contribute to these inequalities in mortality. The author studied income-related inequalities in short-term and long-term case death after first hospitalisation with acute myocardial infarction (AMI) and chronic ischaemic heart disease (CIHD), as well as inequalities in cardiovascular surgical procedures among patients admitted with IHD, in the Netherlands.

Design: A nationwide prospective cohort study of patients first admitted for IHD.

Data: Obtained by record linkage at individual level of national hospital discharge, cause of death, population and income registries.

Patients: 15 416 patients admitted to a hospital with first episode of AMI and 31 209 patients admitted to a hospital with first episode of CIHD in the period 2003-2005.

Main outcome measures: Differences by income quintile in short-term (28 days) and long-term (1 year) case death after first hospital admission with AMI and CIHD. Differences by income quintile in Percutaneous Transluminal Coronary Angioplasty (PTCA) and Coronary Artery Bypass Graft operations among patients with first admission for AMI.

Results: After adjustment for age, ethnicity and comorbidity, men and women in the lower income quintiles had a higher 28-day and 1-year case death after first hospitalisation with an AMI or CIHD. After adjustment for age and comorbidity, patients admitted to the hospital with a first AMI also had a lower probability of undergoing a PTCA procedure if they belonged to a lower income quintile. There were large between-hospital variations in inequalities in 28-day mortality for patients admitted with a first AMI.

Conclusions: Higher mortality from IHD among lower income people is likely to be partly due to higher case death after first hospital admission. Inequalities in utilisation of PTCA and between-hospital variations in inequalities in outcomes suggest that inequalities in access to good quality care may play a role in explaining the higher case death of IHD among people with lower socioeconomic position. Further research is needed to elucidate the causes of these inequalities in case death.