Social inequality in diabetes patients' morbidity patterns from diagnosis to death: A Danish register-based investigation

AIM: Measuring socioeconomic inequalities in health and health care, and understanding determinants of such inequalities, are critical for achieving higher equity in health. Equity in health is a prerequisite for public health and welfare. The aim of the paper is (1) to quantify inequality in diabetes morbidity patterns over patients' entire life span, and (2) to compare levels of inequality measured through income and educational level, respectively, as proxies for socioeconomic status (SES).

METHOD: Historic individual register data on the entire Danish diabetes population alive in 2011 were gathered. Cox survival analysis and a concentration index decomposition approach were applied to analyse relevant morbidity indicators reflecting patients' health state at diagnosis and throughout their lives with diabetes.

RESULTS: Patients with high education have approximately 26% lower mortality hazard when diagnosed with diabetes and 10-15% lower hazard of developing complications as compared with patients with short education. The outcome variables: 'severe complications at diagnosis' and 'years with severe complications' inhibit the highest negative concentration index value, indicating that morbidity is concentrated among the lower SES groups, whereas the outcome variables 'years without complications' and 'duration of diabetes' concentrate among the socioeconomically better-off patients.

CONCLUSIONS: Significant differences in diabetes patients' morbidity patterns and survival indicate that diabetes impacts harder on patients of lower SES; these patients experience more severe complications and die earlier. Hence to reduce inequality in health, it is important to invest in efforts targeted towards socially vulnerable groups.