Type 2 diabetes and a history of coronary heart disease are additive cardiovascular risks in high-risk hypertensive patients: a subanalysis of the CASE-J Ex

Abstract

Objective: Accumulating evidence showed that type 2 diabetes mellitus has the same impact on the incidence of cardiovascular (CV) events as a history of coronary heart disease (CHD). However, there has been little evidence regarding the effect of the combination of type 2 diabetes and a history of CHD on CV risk. The present study was aimed at examining whether the combination of type 2 diabetes and a history of CHD have a synergistic effect on CV risk or not, as a subanalysis of CASE-J Ex. Methods: The CASE-J trial compared the effects of the angiotensin II receptor blocker candesartan and the calcium channel blocker amlodipine on the incidence of CV events in 4,703 high-risk Japanese hypertensive patients. The CASE-J Extension (CASE-J Ex) was an observational study designed to evaluate their long-term effects, incorporating an additional 3-year follow-up of the CASE-J trial. There were 4,703 high-risk hypertensive patients (mean age: 63.8 years) to be analyzed. The primary endpoint was CV events including sudden death, cerebrovascular, cardiac, renal, and vascular events. We used the multiple Cox regression analysis to estimate the hazard ratio (HR) and 95% confidential interval (CI) with adjustment for baseline characteristics (prior antihypertensive treatment, allocated drug, age, sex, body mass index (BMI), a history of cerebrovascular events, LVH, renal dysfunction, peripheral vascular disease, hyperlipidemia, and smoking) as standard covariates, and systolic and diastolic blood pressure during the follow-up period as time-varying covariates. The test for interaction in multiple Cox model was evaluated with the interaction term. Possible confounders Results: Of 4,703 patients, 339 (7.2%) patients experienced CV events for a rate of 15.9 per 1000 person-years during the 4.5±1.9 years of follow-up. Type 2 diabetes and a history of CHD were independent predictors of CV events (type 2 diabetes, adjusted HR: 2.47; 95% CI: 1.97-3.10; P<0.001; a history of CHD, adjusted HR: 2.33; 95% CI: 1.76-3.08; P<0.001). The combination of type 2 diabetes and a history of CHD had no synergistic effect on CV risk (interaction p=0.255) Conclusion: Type 2 diabetes and coronary heart disease are additive cardiovascular risks in high-risk hypertensive patients.