This study aimed to determine changes in absolute and relative socioeconomic inequalities in hospital admissions for major cardiovascular causes among patients with diabetes in England.
Methods
We identified all patients with diabetes aged ≥45 years admitted to the hospital in England between 2004-2005 and 2014-2015 for acute myocardial infarction, stroke, percutaneous coronary intervention, or coronary artery bypass graft. We measured socioeconomic status using the Index of Multiple Deprivation. Diabetes-specific admission rates were calculated for each year by deprivation quintile. We assessed temporal changes using negative binomial regression models.
Results
Most admissions occurred among patients aged ≥65 years (71%) and men (63.3%). The number of admissions increased steadily from the least quintile to the most deprived quintile. Patients in the most deprived quintile had a 1.94-fold increased risk of acute myocardial infarction (95% confidence interval [CI], 1.79-2.10), 1.92-fold increased risk of stroke (95% CI, 1.78-2.07), 1.66-fold increased risk of coronary artery bypass graft (95% CI, 1.50-1.74), and 1.76-fold increased risk of percutaneous coronary intervention (95% CI, 1.64-1.89) compared with the least deprived group. Absolute differences in rates between the least and most deprived quintiles did not change significantly for acute myocardial infarction (P = .29) and were reduced for stroke, coronary artery bypass graft, and percutaneous coronary intervention (by 17.5, 15, and 11.8 per 100,000 patients with diabetes, respectively, P ≤ .01 for all).
Conclusions
Socioeconomic inequalities persist in diabetes-related hospital admissions for major cardiovascular events in England. Besides improved risk stratification strategies that consider socioeconomically defined needs, wide-reaching population-based policy interventions are required to reduce inequalities in diabetes outcomes.
Introduction
Cardiovascular disease remains a leading cause of morbidity and premature mortality and is a substantial contributor to health inequalities globally.1 The risk of morbidity and death, particularly cardiovascular mortality, varies markedly according to socioeconomic status, as measured by income, education, social class, and area-based deprivation indices.2 Lower socioeconomic status is also a powerful predictor of a higher incidence of type 2 diabetes as well as its acute and long-term complications.3 This mirrors the socioeconomic patterning of risk factors such as poor diet, lack of exercise, smoking, psychological stress, and access to and use of evidence-based preventive and therapeutic interventions.3, 4 The fast-growing prevalence of type 2 diabetes with a disproportionate burden on disadvantaged populations represents a serious concern for health systems and societies.
Epidemiologic studies show that despite targeted interventions, inequalities in mortality due to coronary heart disease in the general population have not only persisted but widened since the 1970s in England and other developed countries.2,5, 6, 7 Although absolute inequalities in mortality have narrowed over time as cardiovascular mortality has fallen in all socioeconomic groups, faster decreases in more affluent groups have led to an increase in relative socioeconomic inequalities in many countries.5, 7 It is worrying that there is increasing evidence that health inequality gaps have been widening since 2010 in England alongside reductions in public service funding.8
Although it is extensively studied in the general population, little is known about how patients with diabetes from different socioeconomic groups have benefited from reductions in cardiovascular disease over the past decade. Few longitudinal studies have examined the temporal relations between measures of socioeconomic status and cardiovascular outcomes in diabetes internationally.3,9, 10, 11, 12, 13, 14, 15, 16, 17, 18 Some, but not all, studies have reported widening socioeconomic inequalities in patients with diabetes.9, 10, 11,19 Previous studies have been limited by small sample sizes or short follow-up times or were conducted a long time ago, and most of them have focused on cardiovascular mortality rather than morbidity.
The objective of this nationwide study was to describe hospital admissions for acute myocardial infarction, stroke, percutaneous coronary intervention, and coronary artery bypass graft in patients with diabetes by socioeconomic deprivation between 2004-2005 and 2014-2015 in England. We also assessed whether absolute and relative socioeconomic gradients in study outcomes changed among patients with diabetes during this 11-year period.
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-Zainab Shather, MPH, Anthony A. Laverty, MSc, PhD, Alex Bottle, MSc, PhD, Hilary Watt, CStat, MSc, Azeem Majeed, MD, Christopher Millett, PhD, Eszter P. Vamos, PhD
This article originally appeared in the November issue of The American Journal of Medicine.
