Are there intervention-generated inequalities in type 2 diabetes care? A systematic review and analysis of routine data

Abstract

This thesis aimed to contribute to current understanding of ‘intervention-generated inequalities’, that is, the concern that processes in the planning or delivery of an intervention may create or exacerbate the health differences between population groups. This was done by examining the impact of secondary and tertiary preventive interventions for type 2 diabetes by socio-economic status (SES). Previous research has shown that the condition places a disproportionate burden on individuals from disadvantaged backgrounds. It addition, managing the condition involves a range of health care; all potentially exacerbating existing health inequalities.

A systematic review was conducted and secondary data analyses of patient data collected by a hospital diabetes register. The Index of Multiple Deprivation 2004 was used as an indicator of patients’ SES. Multilevel models were fitted using repeated measurements, with patients nested within general practices. Interaction effects were used to determine inequalities over time and if interventions were associated with differential health outcomes by SES.

The multilevel analyses showed that high SES patients were more likely to have lower blood glucose over time, but higher levels of cholesterol compared to low SES patients. In contrast, there were few differences in long-term health complications by SES over time. High SES patients were more likely to receive higher quality of care and shared care than low SES patients over time. Furthermore, there significant inequalities in health by SES were found in patients receiving the same care. There were also significant inequalities in prescriptions for treatments, conditional on other relevant covariates.

The results in thesis indicate that there were intervention generated inequalities which are particularly important for practitioners. As these were either a result of interventions not being appropriately accessed and/or administered based on need or the efficacy of these interventions differed by SES. Further analyses are needed to unpick the direction of these associations.