Decomposing Inequality in Diabetes Patients' Morbidity Patterns, Survival and Health Care Usage in Denmark

Measurement of socioeconomic inequalities in health and health care, and understanding the determinants of such inequalities, are critical for achieving higher equity in health care through targeted health intervention strategies. The aim of the paper is to quantify inequality in diabetes morbidity patterns, survival and health care service usage and understand determinants of these inequalities in relation to socio-demographic and clinical morbidity factors. Further, to compare income level and educational level as proxies for Socio Economic Status (SES). Data on the entire Danish diabetes population in 2011 were applied. Patients’ unique personal identification number enabled individual patient data from several national registers to be linked. Cox survival method and a concentration index decomposition approach are applied. Results indicate that lower socioeconomic status is associated with higher morbidity, mortality and lower survival. Differences in diabetes patients’ morbidity patterns, time of diagnosis and health state at diagnosis as well as health care utilization patterns suggest that despite the Danish universal health care system use of services differ among patients of lower and higher SES. Especially outpatient services, rehabilitation and specialists in primary care show different usage patterns according to SES. Comparison of educational level and income level as proxy for patients’ SES indicate important differences in inequality estimates. This is a result of reversed causality between diabetes morbidity and income as well as income related inequality to a higher extent being explained by morbidity.