Christine Bengtsson

Cardiovascular event in systemic lupus erythematosus in northern Sweden: Incidence and predictors in a 7-year follow-up study

Introduction. An increased rate of cardiovascular disease (CVD) has been suggested in patients with systemic lupus erythematosus (SLE). The risk for myocardial infarction (MI), coronary artery disease and stroke has been reported as particularly prevalent in younger females compared with the reference population. This study was performed to analyse the standard incidence ratio (SIR) of and predictors for cardiovascular events (CVEs) in patients with SLE from northern Sweden, with a fairly homogenous population. Methods. In 2000 all prevalent patients with SLE (≥4 American College of Rheumatology [ACR] criteria; n = 277) from the four northern-most counties of Sweden were assessed with clinical and laboratory analyses. Seven years follow-up data concerning MI and stroke were extracted from the national registers of hospitalization and death in Sweden. The incidence ratio among the patients was compared with that for the general population from the same catchment area using data from the same register and Statistics Sweden. To identify time to event and CVE predictors, two matched controls for each patient were used and disease related variables as CVD predictors. Results. The SIR for a CVE was 1.27 (95% CI 0.82–1.87) and for females separately aged 40–49 years was 8.00 (95% CI 1.65–23.38). The overall SIR for MI was 2.31 (95% CI 1.34–3.7), for females overall was 1.75 (95% CI 0.84–3.22) and for females aged between 40 and 49 years was 8.7 (95% CI 1.1–31.4). The time to an event was significantly shorter among SLE patients (p < 0.001) and was predicted by hypertension adjusted for smoking and disease. High SLEDAI and anti-cardiolipin IgG antibodies predicted an event in Cox proportional hazards regression models adjusted for age and previous MI. Diabetes, smoking ever and sex did not affect the prediction models. Conclusion. The risk of a CVE, or MI, was eight- or nine-fold greater among middle-aged female SLE patients. Time to event was significantly shorter and CVE was associated with SLE-related factors including hypertension and age.

Increased aortic pulse wave velocity in middle aged women with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a connective tissue disease where inflammatory activity affects several organ systems. An increased risk of cardiovascular disease has been identified in these patients, even after correction for traditional risk factors. The aim of the present study was to evaluate arterial stiffness and central hemodynamics in women with SLE in comparison to controls. Arterial tonometry was used to measure aortic (carotid-femoral) and arm (carotid-radial) pulse wave velocity (PWV), reflected pressure waves, and aortic augmentation index (AIx) in 27 women with SLE (52 to 68 years) and 27 controls. Aortic PWV was higher in women with SLE than controls, 9.8 m/s versus 8.2 m/s (P 0.01), after correction for mean arterial pressure and body mass index, 9.5 m/s versus 8.5 m/s (P 0.05). Other parameters were similar, arm PWV, 8.4 versus 8.5 m/s, AIx 34 versus 33% and calculated central aortic pulse pressure 48 versus 43 mmHg, in SLE and controls, respectively (NS). Aortic PWV was positively associated to C-reactive protein (CRP) and complement factor 3 (C3). Women with SLE have increased stiffness of their elastic central arteries. This may be one factor contributing to the increased cardiovascular risk seen in this cohort.

Abnormal mechanical properties of larger arteries in postmenopausal women with systemic lupus erythematosus.

There is limited knowledge of potential defects in arterial wall properties in female systemic lupus erythematosus (SLE) patients without manifest cardiovascular disease (CVD) and significant atherosclerotic lesions. The aim of the present study was to investigate the mechanical properties of larger vessels in these patients and to compare them with healthy controls. B-mode ultrasound was used to assess vessel wall structure and to exclude presence of plaque. The ankle/brachial pressure index was measured to exclude occlusive arterial disease. An ultrasound echo-tracking system was used to determine stiffness of the abdominal aorta, common carotid artery (CCA) and popliteal artery (PA) in 39 female patientswith SLE and 55 female, healthy controls. SLE had an independent effect on stiffening of the CCA (P = 0.01) and PA (P = 0.005). In addition, larger vessel diameters were observed in the CCA (P = 0.002) after adjustments for the effects of mean arterial pressure and age. Thus, this investigation demonstrated an increased arterial stiffness and signs of premature vascular ageing in the SLE patients without manifest cardiovascular disease and without significant atherosclerotic lesions. The results of this study indicate that other mechanisms besides atherosclerosis might be involved in the pathogenesis of arterial stiffening in SLE patients.

Coronary heart disease in systemic lupus erythematosus is associated with interferon regulatory factor-8 gene variants

Background—Patients with systemic lupus erythematosus have increased morbidity and mortality in coronary heart disease (CHD). We asked whether there was a genetic influence on CHD in systemic lupus erythematosus. Methods and Results—The association between single-nucleotide polymorphisms (SNPs) and CHD in 2 populations of patients with systemic lupus erythematosus was assessed. Patients were genotyped on a custom 12k Illumina Array. The allele frequencies were compared between patients with (n=66) and without (n=509) CHD. We found 61 SNPs with an association (P<0.01) to CHD, with the strongest association for 3 SNPs located in the interferon regulatory factor-8 (IRF8) gene. Comparison of the allele frequencies of these 61 SNPs in patients with (n=27) and without (n=212) CHD in the second study population revealed that 2 SNPs, rs925994 and rs10514610 in IRF8 (linkage disequilibrium, r2=0.84), were associated with CHD in both study populations. Meta-analysis of the SNP rs925994 gave an odds ratio of 3.6 (2.1–6.3), P value 1.9×10–6. The identified IRF8 allele remained as a risk factor for CHD after adjustment for traditional CHD risk factors. The IRF8 risk allele was associated with the presence of carotid plaques (P<0.001) and increased intima-media thickness (P=0.01). By electrophoretic mobility shift assays, we show weaker binding of protein to the risk allele of the highly linked SNP rs11117415, and by flow cytometry, a reduced frequency of circulating B cells was detected in patients with the IRF8 risk allele. Conclusions—There is a considerable genetic component for CHD in systemic lupus erythematosus, with IRF8 as a strong susceptibility locus.

The Extent of Subclinical Atherosclerosis Is Partially Predicted by the Inflammatory Load: A Prospective Study over 5 Years in Patients with Rheumatoid Arthritis and Matched Controls.

Objective. This prospective followup study investigated subclinical atherosclerosis in relation to traditional cardiovascular disease (CVD) risk factors and inflammation in patients with rheumatoid arthritis (RA) recruited at diagnosis compared with controls. Methods. Patients diagnosed with early RA were consecutively recruited into a prospective study. From these, a subgroup aged ≤ 60 years (n = 71) was consecutively included for ultrasound measurement of intima-media thickness (IMT) and flow-mediated dilation (FMD) at inclusion (T0) and after 5 years (T5). Age- and sex-matched controls (n = 40) were also included. Results. In the Wilcoxon signed-rank test, both IMT and FMD were significantly aggravated at T5 compared to baseline in patients with RA, whereas only IMT was significantly increased in controls. In univariate linear regression analyses among patients with RA, the IMT at T5 was significantly associated with age, systolic blood pressure (BP), cholesterol, triglycerides, Systematic Coronary Risk Evaluation (SCORE), and Reynolds Risk Score at baseline (p < 0.05). Similarly, FMD at T5 was significantly inversely associated with age, smoking, systolic BP, SCORE, and Reynolds Risk Score (p < 0.05). A model with standardized predictive value from multiple linear regression models including age, smoking, BP, and blood lipids at baseline significantly predicted the observed value of IMT after 5 years. When also including the area under the curve for the 28-joint Disease Activity Score over 5 years, the observed value of IMT was predicted to a large extent. Conclusion. This prospective study identified an increased subclinical atherosclerosis in patients with RA. In the patients with RA, several traditional CVD risk factors at baseline significantly predicted the extent of subclinical atherosclerosis 5 years later. The inflammatory load over time augmented this prediction.

Novel risk genes for systemic lupus erythematosus predicted by random forest classification

Genome-wide association studies have identified risk loci for SLE, but a large proportion of the genetic contribution to SLE still remains unexplained. To detect novel risk genes, and to predict an individual’s SLE risk we designed a random forest classifier using SNP genotype data generated on the “Immunochip” from 1,160 patients with SLE and 2,711 controls. Using gene importance scores defined by the random forest classifier, we identified 15 potential novel risk genes for SLE. Of them 12 are associated with other autoimmune diseases than SLE, whereas three genes (ZNF804A, CDK1, and MANF) have not previously been associated with autoimmunity. Random forest classification also allowed prediction of patients at risk for lupus nephritis with an area under the curve of 0.94. By allele-specific gene expression analysis we detected cis-regulatory SNPs that affect the expression levels of six of the top 40 genes designed by the random forest analysis, indicating a regulatory role for the identified risk variants. The 40 top genes from the prediction were overrepresented for differential expression in B and T cells according to RNA-sequencing of samples from five healthy donors, with more frequent over-expression in B cells compared to T cells.

Direct and indirect costs for systemic lupus erythematosus in Sweden. A nationwide health economic study based on five defined cohorts

OBJECTIVES The main objectives of this study were to calculate total costs of illness and cost-driving disease features among patients with systemic lupus erythematosus (SLE) in Sweden. METHODS Five cohorts of well-defined SLE patients, located in different parts of the country were merged. Incident and prevalent cases from 2003 through 2010 were included. The American College of Rheumatology (ACR) classification criteria was used. From the local cohorts, data on demographics, disease activity (SLEDAI 2K), and organ damage (SDI) were collected. Costs for inpatient care, specialist outpatient care and drugs were retrieved from national registries at the National Board of Health and Welfare. Indirect costs were calculated based on sickness leave and disability pensions from the Swedish Social Insurance Agency. RESULTS In total, 1029 SLE patients, 88% females, were included, and approximately 75% were below 65 years at the end of follow-up, and thus in working age. The mean number of annual specialist physician visits varied from six to seven; mean annual inpatient days were 3.1-3.6, and mean annual sick leave was 123-148 days, all per patient. The total annual cost was 208,555 SEK (

Is Lipoprotein-Associated Phospholipase A2 a Link between Inflammation and Subclinical Atherosclerosis in Rheumatoid Arthritis?

33,369 = 22,941€), of which direct cost was 63,672kr (

Coronary Heart Disease in Systemic Lupus Erythematosus is Associated with Interferon Regulatory Factor 8 Gene Variants

10,188 = 7004€) and the indirect cost was 144,883 SEK (

Systemic lupus erythematosus and cardiac risk factors : medical record documentation and patient adherence

23,181 = 15,937€), all per patient. The costs for patients with short disease duration were higher. Higher disease activity as measured by a SLEDAI 2K score > 3 was associated with approximately 50% increase in both indirect and direct costs. Damage in the neuropsychiatric and musculoskeletal domains were also linked to higher direct and indirect costs, while organ damage in the renal and ocular systems increased direct costs. CONCLUSION Based on this study and an estimate of slightly more than 6000 SLE patients in Sweden, the total annual cost for SLE in the country is estimated at