Association between coronary artery spasm and the risk of incident diabetes: A nationwide population-based cohort study

Background: Non-diabetic coronary artery spasm (CAS) without obstructive coronary artery disease increases insulin resistance. We investigated the risk of incident type 2 diabetes (diabetes) associated with CAS. Methods: Patient records were retrospectively collected from the Taiwan National Health Insurance Research Database during the period 2000-2012. The matched cohorts consisted of 12,413 patients with CAS and 94,721 patients in the control group. Results: During the entire follow-up, the incidence of newly-diagnosed diabetes was 22.2 events per 1000 person-years in the CAS group and 13.9 events per 1000 person-years in the control group. The increased risk of CAS-related incident diabetes was observed regardless of sex and length of follow-up. The median time to incident diabetes was 2.9 and 3.5 years in the CAS and the control group (P <0.001), respectively, regardless of sex. Although age did not affect the risk of CAS-related incident diabetes, the risk was less apparent in the subgroups of male, dyslipidemia, chronic obstructive pulmonary disease, stroke, gout and medicated hypertension. However, CAS patients aged <50 years compared with patients ≥50 years had a greater risk of incident diabetes in females but not in males. Older CAS patients developed diabetes in a shorter length of time than younger patients. Conclusion: CAS is a risk factor for incident diabetes regardless of sex. However, females aged <50 years have a more apparent risk for CAS-related diabetes than old females, which is not observed in males. The median time of 2.9 years to incident diabetes warrants close follow-up.