Validation of Self-Reported Cardiovascular Disease and Associated Co- Morbidities in a Large Canadian Cohort of Early Inflammatory Arthritis

Abstract

Objective: Cardiovascular disease (CVD) and risk factors for CVD (smoking, hypertension, dyslipidemia and diabetes) are commonly associated with Rheumatoid Arthritis (RA). We aimed to determine the validity of selfreported CVD events and risk factors in the Canadian Early Arthritis Cohort (CATCH). Methods: CATCH is a multicenter inception cohort of patients with early RA. Various co-morbidities and pharmacologic therapies are self-reported at baseline and at each follow-up visit. Using a randomly selected subgroup of subjects enrolled in CATCH from one representative site, we performed a detailed review of their complete medical record to identify diagnoses of CVD events, risk factors and drug therapies. The validity of selfreported variables was determined using the Cohen’s kappa statistic. Results: The validation subgroup (N=141) was similar to the entire CATCH population (N=2626) with respect to baseline demographics and RA disease characteristics. There was very good agreement between self-report and the medical record for cardiovascular or cerebrovascular events (kappa=0.66), as well as for hypertension and diabetes (kappa=0.70 and 0.81, respectively). Subjects tended to under-report dyslipidemia and the reporting of lipid-lowering and antiplatelet/anticoagulant agents was inaccurate compared to the medical record. Conclusion: Self-reported cardiovascular disease, hypertension and diabetes was representative of the medical record suggesting that these self-reported variables are valuable for future studies of this early RA population.