Background/Purpose: To assess socioeconomic (SES), gender, urban-rural, and regional disparities in the risk of acute myocardial infarction (MI) among rheumatoid arthritis patients.

Methods: We conducted a population-based cohort study using administrative health data on all individuals with RA across an entire Canadian province. RA incident cases were defined as first meeting previously published RA criteria between 1997 and 2009, using a 7 year wash-out period. Individuals with prior MI were excluded. The outcome was the first ever ICD code (ICD9 410 or ICD10 I21) for MI recorded in Hospital Discharge Data (in any position) or as the primary cause of death in Vital Statistics Data. Follow-up was from incident RA date to the date of first MI event, death, leaving the province, or March 31, 2015, whichever occurred first. We obtained patients’ residency information, such as postal code and health regional authority (HA) from patient registry database, where a zero ‘0’ in the second position of the postal code indicates a rural area. We defined low-income if an individual received a family-income-based MSP premium subsidy.

We compared disparities in incident rates (IR) of MI by SES, gender, rural/urban area and HA. We further estimated their hazard ratios (HR) using Cox proportional hazard model  to evaluate the SES, gender, rural residency, and HA disparities in MI, adjusting for potential confounders.

Results: A total of 37,547 incident RA patients were identified, including 12,546 (33.4%) male, 6,527 (17.4%) rural, and 12,838 (34.2%) low income patients. Overall, 2,076 patients developed MI during 378,586 follow-up years with an incident rate of 5.5 per 1,000 person-years (PYs). The MI IRs varied with SES (low vs. med-high: 6.6 vs 4.9 per 1000 PYs), gender (male vs female:.8.1 vs 4.2), rural residency (rural vs urban: 6.4 vs 5.3), and HA (Interior 7.0, Fraser 5.0, Vancouver Coastal 4.7, Vancouver Island 5.1, Northern 6.1).

Adjusting for age, number of GP visits, prior hospital admission, comorbidities and medication use, low socioeconomic status (HR= 1.14, 95%CI=1.04~1.26, p=0.005), and male gender (HR=1.95, 95%CI=1.78~2.14, p< 0.001), rural residency (HR=1.13, 95%CI=1.01~1.27, p=0.038) were associated with an increased risk of MI. Compared with Vancouver Coastal HA, residency in Interior (HR=1.3, 95%CI=1.13~1.49, p< 0.001), and Northern HA (HR=1.62, 95%CI=1.35~1.94, p< 0.001) was associated with a higher risk of MI, but not Fraser (HR=1.05, 95%CI=0.92 ~1.20, p=0.46) or Vancouver Island HA (HR=0.99, 95%CI=0.85~1.14, p=0.85).

Conclusion: RA patients with a lower SES and male gender, and living in rural areas were more likely to develop a MI. Living in remote communities, such as Interior and Northern HA, were also associated with a higher risk of MI. These findings have important implications for patients, health care providers and health policy makers; and point to the need for further investigations to understand the underlying reasons for the differences identified, so that targeted interventions can be designed to address health inequities.

table 1

table 2

table 3

« Back to 2019 ACR/ARP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-socioeconomic-gender-urban-rural-and-regional-disparities-in-the-risk-of-acute-myocardial-infarction-among-ra-patients/