Background/Purpose:

We have previously demonstrated that RA patients have higher post-myocardial infarction (MI) case fatality than controls [1] and that treatment with secondary prevention medications is lower in RA patients than matched controls [2].  More recently we have demonstrated that post-MI case fatality is also higher in the larger group of patients with auto-immune rheumatic disease (AIRD) such as lupus, spondyloarthritis, scleroderma and systemic necrotising vasculitis [manuscript in preparation]. The aim of this study was to compare the utilization of lipid-lowering agents (statins), beta-blockers (BB) and angiotensin converting enzyme  inhibitors (ACE-I) following MI in patients with AIRD compared to patients without AIRD.

Methods: A retrospective cohort study utilising a population-based dataset containing statewide hospital admission data linked with medication utilisation data.  Data were available from 1 July 2001 to 30 July 2009.  Cases of MI were identified from hospital admission data based on relevant International Classification of Diseases (ICD) codes. AIRD status was identified from the index MI admission or any admission in the preceding 5 years using relevant ICD codes.  Relevant co-morbidities including cardiovascular risk factors were identified using ICD codes from the index MI admission. Adjusted odds ratios (OR) for post-MI treatment with each of the specified medications in AIRD patients compared to non-AIRD patients were estimated using a logistic regression model with adjustment for age, gender, socio-economic status, geographic location and relevant co-morbidities.

Results: :  There were 21,126 individuals with an index MI, of whom 518 (2.5%) were identified as AIRD patients. The rate of statin use within 12 months post MI for patients with AIRD was 52.7% compared to 69.8% for patients without AIRD (p<0.001). A decreased rate of BB and ACE-I use was also identified for AIRD patients compared to non-AIRD patients (BB: 49.4% vs 55.6 %, p<0.005 and ACE-I: 50.2% vs 58.3%, p<0.001). The adjusted OR for statin use within 12 months post MI for AIRD patients was 0.57 (95% CI: 0.45 – 0.73). The adjusted ORs for usage of BB and ACE-I in AIRD patients within 12 months of the MI were reduced but not statistically significant after adjustment for covariates (BB: OR = 0.86, 95% CI: 0.69–1.08 and ACE-I: OR = 0.84, 0.68–1.03).

Conclusion:

Treatment with statins in the 12 months following MI is significantly lower for patients with AIRD, even after adjustment for potential confounders.  Lower rates of usage of BB and ACE-I were also found, although these differences were not statistically significant after adjustment for relevant co-variates.

[1] Van Doornum et al. 2006

[2] Van Doornum et al. 2010

---

« Back to 2013 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/comparison-of-medication-usage-following-myocardial-infarction-in-patients-with-autoimmune-rheumatic-disease-versus-controls/