Rheumatoid arthritis and risk of acute myocardial infarction-A nationwide retrospective cohort study

Objectives: Rheumatoid arthritis (RA) imposes substantial social costs, including an increased risk ofwork-related disability and accelerated cardiovascular diseases. The aim of the study is to determine the risk of acute myocardial infarction (AMI) associated with RA in a nationwide retrospective cohort study. Methods: Using the catastrophic illness registry of the Taiwan National Health Insurance Research Database (NHIRD), we identified patients with RA from 1998 to 2010. We also randomly selected non-RA controls frequency-matched by age, sex, and index year from the general population free of RA. The risk of AMI was analyzed using Cox proportional hazards regression models including sex, age, and comorbidities. Results: Froma total of 23.74 million people in the cohort, 29,260 RA patients and 117,040 controlswere followed for 193,987 and 792,254 person-years, respectively. The incidence density rate increased in all groups of RA patients than those of the controls. RA patients had a 1.33-fold higher overall incidence of AMI than controls, with an adjusted hazard ration of 1.38. Although the overall adjusted hazard ratio of AMI increased with age, the agespecific RA patients to controls incidence rate ratio was higher for younger RA patients. Subjects with comorbidities of hypertension, diabetes hyperlipidemia, CVA, COPD, or ESRD had increased risk of AMI. Subjects with ESRD had the highest hazard of AMI. Conclusion: This nationwide retrospective cohort study indicates that AMI risk increased by 38% in RA patients compared to the general population. Comorbidities increase the AMI risk independently. (C) 2013 Elsevier Ireland Ltd. All rights reserved.