An analysis of the metabolic syndrome phenotype in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is associated with an increased risk of coronary heart disease (CHD) not fully explained by classic risk factors. Metabolic syndrome (MetS) is associated with an increased risk of CHD in the general population and whilst its prevalence is increased in SLE, its phenotypic expression may differ. We studied 200 women with SLE and 100 controls and compared the prevalence of MetS and its individual components. We examined whether any SLE features were associated with MetS and whether MetS in SLE patients was associated with carotid plaque. Patients with SLE were more likely to meet the MetS criteria (age-adjusted OR 2.1 (1.1-3.8)). However, this was not due to increased central obesity (median waist circumference 84 cm vs. 82 cm, p = 0.65) but rather increased prevalence of hypertension (p <0.01) and low HDL-cholesterol (p = 0.01). In a multivariable analysis, age, disease duration, low complement C3 and corticosteroid use ever, were associated with the presence of MetS in SLE. Overall MetS was not associated with the presence of carotid plaque in either SLE or controls. We have shown that MetS is more prevalent in SLE, but the lupus-MetS phenotype reflects risk factor changes driven by disease activity and steroid exposure, rather than obesity. Reliance on clinical measures of central obesity to consider MetS in SLE is not reliable and continued attention to individual CHD risk factors is recommended.

Health-related quality of life, smoking and carotid atherosclerosis in white British women with systemic lupus erythematosus

We tested the hypothesis that carotid atherosclerosis in systemic lupus erythematosus (SLE) is associated with poor health-related quality of life (HRQOL), which is independent of any association with traditional risk factors (TRFs), lifestyle and socioeconomic factors. Women with SLE completed the RAND Medical Outcome Study 36-Item Short-Form Health Survey version 1 (MOS SF-36). B-mode Doppler examination of the carotid arteries determined the presence of atherosclerotic plaque. The association between carotid plaque and HRQOL domains was analysed using logistic regression models with sequential adjustments for age, TRFs, education level and employment status. We studied 181 women, 47 (26%) of whom had carotid plaque. Carotid plaque was significantly associated with lower levels of physical functioning (p = 0.047), vitality (p = 0.04), role emotional (p = 0.04) and mental health subscales (p = 0.01) and lower mental component summary score (MCS) (p = 0.03). These associations were no longer significant after adjustment for age and TRFs, especially smoking. Smokers had lower physical functioning, vitality and mental health and more bodily pain. The association between carotid plaque and HRQOL was not independent of TRFs and smoking was a key mediator of the associations found. Poor HRQOL in smokers will need addressing as part of any smoking cessation strategies in SLE patients.

Subclinical atherosclerosis in systemic lupus erythematosus (SLE): the relative contribution of classic risk factors and the lupus phenotype

OBJECTIVES

We aimed to examine the strength of association between traditional cardiovascular risk factors and carotid plaque development in systemic lupus erythematosus (SLE) patients and controls. We also aimed to determine which lupus-related factors are associated with carotid plaque and whether SLE sensitizes patients to the effects of traditional factors.

METHODS

We studied 200 women with SLE and 100 controls. Demographic and risk factor data were collected and SLE features, including autoantibody profiles and therapy were noted. All subjects had B- mode ultrasound of their carotid arteries examined for the presence and distribution of plaque.

RESULTS

SLE patients <55 years old had more plaque (21% vs 3% P < 0.01) and more SLE patients had plaque in the internal carotid artery (11% vs 4%; P < 0.05). Traditional risk factor models performed less well in SLE compared with controls [area under Receiver Operator Characteristic curves (AUC ROC) = 0.76 vs 0.90; P < 0.01]. A multivariable model using SLE factors only, performed significantly better (AUC ROC = 0.87; P < 0.01). The final model in SLE included age and cigarette pack-years smoking as well as azathioprine exposure ever, antiphospholipid antibodies (APLA) and previous arterial events (AUC ROC = 0.88).

CONCLUSIONS

SLE patients have a higher prevalence and different distribution of carotid plaque than controls. SLE factors perform significantly better than traditional risk factors in their association with atherosclerosis in SLE and these factors add to the influence of traditional risk factors rather than sensitizing lupus patients to traditional factors. The SLE phenotype helps identify patients at increased risk of atherosclerosis.