Impact of Hypertension, Diabetes and Dyslipidemia on Ischemic Heart Disease among Japanese: A Case-Control Study Based on National Health Insurance Medical Claims

Aim Although the important role of conventional risk factors (cigarette smoking, hypertension, diabetes and dyslipidemia) inthe pathogenesis of ischemic heart disease (IHD) has been established, how frequently IHD is preceded by exposure to conventionalrisk factors remains controversial. The present study aimed to identify the prevalence of hypertension, diabetes anddyslipidemia among patients with IHD and examine associations between each of them with IHD in a Japanese population.Methods Data were collected from health insurance claims in May 2010 for National Health Insurance beneficiaries aged 40-79 years in Nagasaki Prefecture, Japan. One sex- and age-matched control was randomly selected for each of 42,236 patientswith IHD (International Classification of Diseases, 10th Revision code: I20-25). The prevalence of hypertension, diabetes anddyslipidemia and the number of these risk factors were compared between the patients and controls. Associations betweenrisk factors and IHD were examined using a conditional logistic regression model.Results Over 90% of patients with IHD had at least one of hypertension, diabetes or dyslipidemia. The odds of IHD were 4.5-fold (95% confidence interval [CI]: 4.3, 4.7), 4.2-fold (95% CI: 3.9, 4.6) and 5.3-fold (95% CI: 4.9, 5.7) higher for patients withhypertension, diabetes and dyslipidemia, respectively, compared with patients without any of these risk factors. Patients withseveral risk factors were at increased risk for IHD.Conclusion Comprehensive risk reduction strategies that encourage a healthy lifestyle and diet and promote the recognition,evaluation and management of conventional risk factors are important to prevent IHD