Identifying Causes for Excess Mortality in Patients With Diabetes: Closer but Not There Yet

Abstract

Diabetes is a chronic disease associated with increased morbidity and mortality (1), mainly from cardiovascular disease (2–6). Treatment of diabetes includes normalizing hyperglycemia to attain glycemic targets and treatment of cardiovascular risk factors such as hypertension and dyslipidemia. This multifactorial intervention strategy has been shown to decrease cardiovascular and all-cause mortality among patients with type 2 diabetes (7). Nevertheless, mortality in diabetes remains elevated (2,5). A number of epidemiological studies have quantified the risk of death among patients with diabetes and assessed the causes of death (2–6), with highly varying results (Table 1). The South Tees Diabetes Mortality Study (2) found an over threefold increase in all-cause mortality, mainly attributed to increased cardiovascular deaths, but found no increased risk of cancer mortality. The Australian Diabetes, Obesity and Lifestyle Study (AusDiab) (3) of over 10,000 individuals reported a little over twofold increase in the risk of all-cause mortality, with the majority due to cardiovascular causes. The Emerging Risk Factors Collaboration (ERFC) study (6), involving over 800,000 individuals, reported a little under twofold increase in the risk of all-cause mortality associated with diabetes. It also found that diabetes was associated with an increased risk of death from cancer (hazard ratio [HR] 1.25 [95% CI 1.19–1.31]), from vascular disease (HR 2.32 [95% CI 2.11–2.56]), and from nonvascular and noncancer etiologies (HR 1.73 [95% CI 1.62–1.85]). More recently, a study using the Swedish National Diabetes Register (5) on over 400,000 patients with type 2 diabetes matched to more than 2 million subjects …