Do social inequalities exist in terms of the prevention, diagnosis, treatment, control and monitoring of diabetes? A systematic review.

The major increase in the prevalence of diabetes mellitus (DM) has led to the study of social inequalities in health-care. The aim of this study is to establish the possible existence of social inequalities in the prevention, diagnosis, treatment, control and monitoring of diabetes in Organisation for Economic Co-operation and Development (OECD) countries which have universal healthcare systems. We searched MEDLINE, EMBASE and the Cochrane Database of Systematic Reviews for all relevant articles published up to 15 December 2007. We included observational studies carried out in OECD countries with universal healthcare systems in place that investigate social inequalities in the provision of health-care to diabetes patients. Two independent reviewers carried out the critical assessment using the STROBE tool items considered most adequate for the evaluation of the methodological quality. We selected 41 articles from which we critically assessed 25 (18 cross-sectional, 6 cohorts, 1 case-control). Consistency among the article results was found regarding the existence of ethnic inequalities in treatment, metabolic control and use of healthcare services. Socioeconomic inequalities were also found in the diagnosis and control of the disease, but no evidence of any gender inequalities was found. In general, the methodological quality of the articles was moderate with insufficient information in the majority of cases to rule out bias. This review shows that even in countries with a significant level of economic development and which have universal healthcare systems in place which endeavour to provide medical care to the entire population, socioeconomic and ethnic inequalities can be identified in the provision of health-care to DM sufferers. However, higher quality and follow-up articles are needed to confirm these results.