Long-term mortality in patients with type 2 diabetes undergoing coronary angiography: the impact of glucose-lowering treatment

Abstract

Aims/hypothesis The aim of this study was to analyse whether the increased mortality rates observed in insulintreated patients with type 2 diabetes and coronary artery disease are explained by comorbidities and complications. Methods A retrospective analysis of data from two Swedish registries of type 2 diabetic patients (n012,515) undergoing coronary angiography between the years 2001 and 2009 was conducted. The association between glucose-lowering treatment and long-term mortality was studied after extensive adjustment for cardiovascular-and diabetes-related confounders. Patients were classified into four groups, according to glucose-lowering treatment: diet alone; oral therapy alone; insulin in combination with oral therapy; and insulin alone.Results After a mean follow-up time of 4.14 years, absolute mortality rates for patients treated with diet alone, oral therapy alone, insulin in combination with oral therapy and insulin alone were 19.2%, 17.4%, 22.9% and 28.1%, respectively. Compared with diet alone, insulin in combination with oral therapy (HR 1.27; 95% CI 1.12, 1.43) and insulin alone (HR 1.62; 95% CI 1.44, 1.83) were associated with higher mortality rates. After adjustment for baseline differences, insulin in combination with oral glucoselowering treatment (HR 1.22; 95% CI 1.06, 1.40; p < 0.005) and treatment with insulin only (HR 1.17; 95% CI 1.02, 1.35; p<0.01) remained independent predictors for long-term mortality. Conclusions/interpretation Type 2 diabetes patients treated with insulin and undergoing coronary angiography have a higher long-term mortality risk after adjustment for measured confounders. Further research is needed to evaluate the optimal glucose-lowering treatment for these high-risk patients.

Insulin Resistance as a Physiological Defense Against Metabolic Stress: Implications for the Management of Subsets of Type 2 Diabetes

“…Population-based studies in patients with T2D reported recently from Canada, the U.K., and Sweden have shown, after correction for multiple factors, increased risk of mortality in patients with T2D treated with insulin (61–63). A follow-up analysis of DIGAMI 2, using the total cohort as an epidemiological database, also showed that insulin therapy from the time of hospital discharge was associated with a significant increased risk of the composite of death, reinfarction, or stroke (HR 1.78 [95% CI 1.14–2.40]) (57).…”

High Event Rate After a First Percutaneous Coronary Intervention in Patients With Diabetes Mellitus

“…In a recent report on patients with type 2 diabetes mellitus undergoing coronary angiography, where such variables were adjusted for, the increased mortality risk related to insulin treatment was reduced but was still apparent. 26 So, it was not possible to rule out whether insulin per se affects the event rate or whether the use of insulin therapy is a risk variable confounded by indication. On the contrary, data from the recent Outcome Reduction With Initial Glargine Intervention (ORIGIN) study 27 contradict this former possibility, showing a neutral effect of insulin on cardiovascular outcome compared with standard glucose care in individuals at high cardiovascular risk and previously insulin naïve patients.…”

Relationship between preoperative hemoglobin A1c levels and long-term mortality after coronary artery bypass grafting in patients with type 2 diabetes mellitus

“…One large clinical trial found that treatment with insulin in patients with myocardial infarction was associated with an enhanced risk of recurrent nonfatal myocardial infarction or stroke, while treatment with metformin was more beneficial [5]. Another study found that insulin treatment with or without oral glucose-lowering therapy was associated with higher long-term mortality in patients with DM undergoing coronary angiography [6].…”