Anagha Nadkarni, Min You, Holly Resuehr and Jeffrey R Curtis
Objectives: To determine, using data from a real-world setting, the overall and sex-specific risk of cardiovascular (CV) events in patients with rheumatoid arthritis (RA), with or without comorbid hyperlipidemia, relative to those in a non-RA cohort.
Methods: This retrospective cohort study using claims data from a US commercial health plan (2005–2011) included patients with RA and a matched non-RA cohort. Cox proportional hazards regression model determined the hazard ratio (HR) for CV events (myocardial infarction, stroke, revascularization procedures), using the presence of RA and hyperlipidemia as the independent variables, controlling for other covariates (age, sex, diabetes, and hypertension).
Results: The incidence of CV events per 1000 person-years was 10.19 for the RA cohort and 6.41 for the non- RA cohort (crude rate ratio [RR] =1.59). Within the RA cohort, incidence was 15.54 for patients with hyperlipidemia and 7.05 for patients without hyperlipidemia (crude RR=2.21); in the non-RA cohort, incidence was 10.55 and 3.82 for those with and without hyperlipidemia, respectively (crude RR=2.76). After controlling for covariates, the HR of CV events among RA patients was 1.68 (95% CI: 1.50, 1.87) relative to non-RA patients. After multivariable adjustment, hyperlipidemia conferred a significant risk of CV events in both RA and non-RA patients; the interaction between RA and hyperlipidemia was not significant (p=0.13).
Conclusion: This real-world analysis demonstrates that patients with RA have an increased risk of CV events. Similar to a non-RA cohort, CV event rates were incrementally higher for those patients with hyperlipidemia.
Significance
• Cardiovascular disease is an increasingly visible topic of concern in the rheumatoid arthritis community. However, there are only limited data that informs both the absolute and relative rates of CVD events, and the contribution of various risk factors such as hyperlipidemia, compared to non-RA populations
• The ‘lipid paradox’ hypothesis in RA suggests that elevated LDL cholesterol has a negligible effect on CVD risk in RA, unlikely in the general population where it is a well-accepted CVD risk factor
• The incidence of CVD events in RA patients was 10/1000 patient years, a 1.6 fold greater risk compared to non-RA patients The contribution of hyperlipidemia to CVD risk was associated with comparable or greater absolute increases in the rate of CV events compared to non RA patients, a finding that does not support the lipid paradox.