Background/Purpose: Patients with RA have high risk for myocardial infarction (MI). A meta-analysis showed that the age and sex adjusted pooled relative risk of MI among patients with RA was 1.69, 95% confidence interval (CI) 1.50 – 1.90. There is limited understanding about the prevalence and incidence of MI events among individuals younger than 65 years of age disabled (defined as beneficiaries of the social security disability insurance (SSDI)) with RA. 

Among patients with RA < 65 years of age who receive SSDI benefits in 2011, to 1) determine the prevalence of cardiovascular disease (CVD) and CVD risk factors; and 2) among those free of CVD at baseline, to compare the risk of incident MI among those with and without CVD risk factors at baseline, to compare the risk of incident MI among those with and without CVD risk factors at baseline.

Methods: We analyzed claims data of the SSDI beneficiaries aged 18-64 years of age with RA, defined as ≥2 ICD-9 CM codes (714.xx) from a rheumatologist > 7 and < 365 days apart, OR 1 ICD-9-CM code from a rheumatologist AND a DMARD in 2011 in a period > 7 and < 365 days. Prevalent CVD was defined by ICD-9-CM code from heart failure, stroke, or CVD procedures (coronary artery bypass grafting, percutaneous coronary intervention, or carotid endartherectomy) in 2011. We used the chronic conditions data warehouse to identify CVD risk factors (ICD-9-CM codes for diabetes, hyperlipidemia, hypertension, obesity) in 2011. We followed subjects without prevalent CVD in 2011, through 2014 to determine incident MI, defined as the first hospitalization for MI (discharge diagnosis ICD-9-CM codes 410.xx). Age adjusted incidence rates were estimated using Poisson models. Age- and sex-adjusted Cox proportional hazard model was used to compare the risk for incident MI between patients with and without CVD factors at baseline.

Results: There were 48,905 patients in the study sample; 78.9% were female, 72.2% were ≤60 years of age, and 69% had at least one CVD risk factor, with hypertension being the most prevalent (52.7%) (Table 1). The prevalence of CVD was 9.3% (N = 4,528). Among the 44,377 without CVD at baseline, 28,538 (64%) had baseline CVD risk factors; 433 MI events occurred among those with CVD risk factors and 143 among those without over 35.9 median months of follow-up (Table 2). The age-adjusted incident rate of MI was 5.02 (95% CI 4.52 – 5.58) per 1000 person-years for those with CVD risk factors and 3.42 (95% CI 2.90 – 4.03) per 1000 person-years for those without CVD risk factors. The age- and sex-adjusted hazard ratio (HR) for incident MI for those with CVD risk factors compared to those without was 1.47 (95% CI 1.22-1.78).

Conclusion: The prevalence of CVD and CVD risk factors was high in this population of disabled individuals younger than 65 years of age with RA. The incident rate for MI was high in the subgroup of patients without CVD risk factors considering that 80% of those patients were 60 year of age or younger (3.42 per 1000 person-year). As expected, patients with CVD risk factors were 47% more likely to experience an MI compare to patients without CVD risk factors.

Table 1 ACR abstract_v2

Table 2 ACR abstract

« Back to 2019 ACR/ARP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/risk-of-incident-myocardial-infarction-among-disabled-patients-with-rheumatoid-arthritis-who-were-beneficiaries-of-the-social-security-disability-insurance/