Arthritis & Rheumatism, Volume 60,
October 2009 Abstract Supplement
The 2009 ACR/ARHP Annual Scientific Meeting
Philadelphia October 16-21, 2009.
Relative Importance of Remote, Recent and Cumulative Exposure to Risk Factors for Atherosclerotic Coronary Events in SLE
Nikpour, Mandana, Ibanez, Dominique, Gladman, Dafna D., Harvey, Paula, Urowitz, Murray B.
SLE is strongly associated with premature coronary artery disease. Traditional risk factors as defined in the Framingham model only partly account for the increased risk of coronary events in SLE. Furthermore, many of these risk factors take a dynamic course in SLE, fluctuating over time due to changes in disease activity or treatment.
To compare 'summary measures' of cumulative exposure with first available ('remote') and recent values for each of total cholesterol (TC), systolic (SBP) and diastolic (DBP) blood pressure in terms of ability to estimate hazard of subsequent coronary events in SLE.
Using a single centre SLE database, patients with two or more measurements of TC and BP taken before a coronary event (or last clinic visit) were included. For each patient, for each of TC, SBP and DBP, arithmetic mean, 'time-adjusted' mean (AM) and area-under-the-curve (AUC) was calculated for all serial measurements up to and including the visit before outcome. Cox and time-dependent proportional hazards regression models were used to compare summary measures with most recent and first available ('remote') measurements of each of TC, SBP and DBP in terms of ability to estimate risk of coronary event. Demographic, disease and treatment related variables were included as covariates in the models.
There were over 950 patients with a mean±SD of 20±20 serial measurements of TC and BP per patient, and a mean±SD time interval between measurements of 4.2±2.3 months. Over a mean±SD follow-up of 7.0±6.7 years, among patient in the TC and BP analyses, there were 86 (71 angina, 22 MI, 2 sudden cardiac death; SCD) and 94 (75 angina, 28 MI, 2 SCD) 'first' coronary events respectively. While first available TC was not significantly predictive of coronary event, mean and AM TC were more strongly predictive (HR 2.07, p=0.003 for both mean and AM) than most recent TC (HR 1.86, p=0.001). Mean (HR 1.03, p=0.04) and AM (HR 1.03, p=0.03) DBP were significantly predictive of coronary events while first available and most recent DBP were not. Results were similar for SBP. AUC was not predictive of coronary event for either TC or BP. Other covariates in the models that were significantly predictive of coronary events were older age (HR in TC models: 1.12; HR in BP models 1.05, p<0.0001), male sex (HR 1.86, p=0.04), higher recent disease activity score (HR 1.1, p<0.0001) and recent treatment with corticosteroids (in TC models only; HR 1.87, p=0.01).
In contrast to the population-based Framingham model, first available ('remote') measurement of TC and BP is not significantly predictive of subsequent coronary events among patients with SLE. In SLE, summary measures of cholesterol and BP, reflecting cumulative exposure over time are better able to estimate risk of future coronary events.
To cite this abstract, please use the following information:
Nikpour, Mandana, Ibanez, Dominique, Gladman, Dafna D., Harvey, Paula, Urowitz, Murray B.; Relative Importance of Remote, Recent and Cumulative Exposure to Risk Factors for Atherosclerotic Coronary Events in SLE [abstract]. Arthritis Rheum 2009;60 Suppl 10 :1550