Rheumatoid arthritis and risk of acute myocardial infarction--a nationwide retrospective cohort study.
OBJECTIVE
Rheumatoid arthritis (RA) imposes substantial social costs, including an increased risk of work-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
From a total of 23.74 million people in the cohort, 29,260 RA patients and 117,040 controls were 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 age-specific 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.


CONCLUSIONS
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.
Department of Internal Medicine, Taichung Hospital, Department of Health, Executive Yuan, Taichung, Taiwan; Department of Healthcare Administration, Central Taiwan University of Science and Technology, Taichung, Taiwan.
Wei-Sheng
WS
Chung
Cheng-Li
CL
Lin
Chiao-Ling
CL
Peng
Yung-Fu
YF
Chen
Chuan-Chin
CC
Lu
Fung-Chang
FC
Sung
Chia-Hung
CH
Kao
D000328:Adult; D017677:Age Distribution; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000150:complications* / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology / Q000209:etiology*; D011159:Population Surveillance / Q000379:methods*; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D017678:Sex Distribution; D013624:Taiwan / Q000453:epidemiology
Acute myocardial infarction; Cohort study; Rheumatoid arthritis