Background Risk prediction models for Cardiovascular Disease (CVD) are based on known risk factors and are used to guide therapy. Amongst these, the Framingham Risk Equation (“Framingham Score”)1 is perhaps most well-known and attempts to moderate risk by targeting ideal lipid and blood pressure levels in those identified as high-risk (defined as an estimated 10-year CVD risk>15%). Systemic Lupus Erythematosus (SLE) is associated with increased CVD risk despite these patients not conforming to conventional CVD risk profiles. Petri et al have described a novel SLE-specific cardiovascular risk equation (“SLE Score”)2 that incorporates SLE disease parameters in addition to conventional risk factors.
Objectives To determine the prevalence of high CVD risk amongst a SLE cohort, and to assess the characteristics of patients who might be missed when using conventional CVD risk assessments.
Methods Using data collected via the Monash Lupus Clinic, patients meeting ≥4/11 ACR diagnostic criteria for SLE were studied. A cross-sectional analysis using the most recent data for each patient was used to categorise patient risk via both the “Framingham Score” and “SLE Scores”. The characteristics of patients identified as “high-risk” by the SLE Score only (termed the “missed group”) were compared to those identified by the Framingham score (the “conventional group”) using non-parametric tests (Mann-Whitney U test for continuous and Fisher's exact test for categorical variables).
Results Of 184 patients screened, 146 (79%) had complete data for calculation of the CVD risk scores. Overall, 22 (15%) and 44 (30%) of patients were determined to be at “high-risk” based on the Framingham and SLE Scores respectively. Traditional risk factors such as smoking (18.5%), diabetes (2%) and hypertension (18.5%) were generally lower in this lupus cohort than similar age-matched population rates.3 Using the SLE Score, 18% (n=27) of patients were newly assigned as high-risk. The “missed group” lacked traditional risk factors, being more likely to be female (81% vs 50%; p-value 0.03), younger (mean age 54 vs 69 years p<0.01), with lower blood pressure (systolic BP 132 vs 143; p=0.05) and body-mass index (24.1 vs 28.0 kg/m2; p value 0.02). Of the 49 participants deemed high-risk via either score, 12 (25%) and 2 (4%) were appropriately treated to target BP and lipid targets respectively.
Conclusions In this cross-sectional comparison between cardiovascular risk prediction models, a significant proportion of patients were re-classified as high-risk using a formula that incorporates SLE disease-related parameters. Females were underrepresented using the Framingham Risk Equation, and conventional risk factors were not increased in SLE patients- suggesting a disease specific CVD risk profile. Further evaluation of the disease-specific risk calculator is warranted in long-term prospective studies, including focus on appropriate blood pressure and lipid levels.
Boston U. Framingham Heart Study. Cardiovascular Disease (10-year risk) Boston2015 [cited 2015 20th March]. Available from: https://www.framinghamheartstudy.org/risk-functions/cardiovascular-disease/10-year-risk.php/p>
Petri M LS. Systemic Lupus Erythematosus Cardiovascular Risk Equation. [abstract]. Arthritis Rheum. 2012;64(10).
Statistics ABO. Australian Health Survey: First Results, 2011–2012-Australia. Canberra: ABS, 2012 29th October. Report No.: Contract No.: 4364.0.
Disclosure of Interest None declared