Association of acute myocardial infarction with seropositive rheumatoid arthritis in Korea: A nationwide longitudinal cohort study

Background: The aim of this nationwide age- and sex matched longitudinal follow up study is to determine the risk of acute myocardial infarction (AMI) associated with the seropositive rheumatoid arthritis (RA) population in Korea.

Methods: Patient data were collected from the National Health Insurance Service Health Screening cohort. RA was identified using the International Classification of Diseases code M05 (seropositive RA), with a prescription of any disease-modifying anti-rheumatic drug (DMARD). A total of 2,765 patients were enrolled in the seropositive RA group from January 1, 2004 to December 31, 2015 from the NHIS. The control group consisted of 13,825 subjects. The 12-years AMI incidence rate for each group was calculated using the Kaplan-Meier method. A Cox proportional-hazards regression analysis was used to estimate the hazard ratio of AMI.

Results: During the follow-up period, 39 patients (1.41%) in the seropositive RA group and 111 (0.80%) in the control group experienced AMI (P = 0.003). The hazard ratio of AMI in the seropositive RA group was 3.879 (95% confidence interval (CI): 2.64-5.68) after adjusting for age and sex. The adjusted hazard ratio of AMI in the seropositive RA group was 4.212 (95% CI: 2.86-6.19) after adjusting for demographics and comorbid medical disorders. According to subgroup analysis, in male and female and the non-diabetes and non-hypertension and hypertension and dyslipidemia and non-dyslipidemia subgroups, AMI incidence rates were significantly higher in the seropositive RA group than in the control group.

Conclusion: Our nationwide longitudinal study suggests an increased risk of AMI in seropositive RA patients.

Keywords: Epidemiology; Myocardial infarction; Population; Rheumatoid arthritis.