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OBJECTIVES: To investigate the relationship between biomarkers known to be involved in both chronic inflammation and subclinical atherosclerosis, as measured by carotid intima media thickness (cIMT), in patients with RA compared to controls.

METHODS: Between 2000 and 2004, all patients under 60 years of age with newly diagnosed RA in the northern region of Sweden were invited to participate in this study. Measurements of cIMT were undertaken at inclusion (T0), after five years of follow-up (T5) and after eleven years of follow-up (T11). Patients were clinically assessed and blood was drawn for analysis of biomarkers.

RESULTS: In patients with RA (n=54), linear regression models showed that cIMT at T11 was associated with levels of GDF-15 at T5 and T11, but not with baseline levels. GDF-15 was strongly associated with age. At T11, mean level of GDF-15 was elevated compared to controls. Levels of adiponectin, MCP-1, cathepsin S, endoglin and IL-6 were higher in patients with RA compared to controls, but showed no association with cIMT. In multivariable linear regression models with cIMT at T11 as dependent variable, change in GDF-15 from T0 to T11 was associated to an increase in cIMT at T11. Adjusting for systolic blood pressure and age respectively rendered this association statistically non-significant,

CONCLUSIONS: Among these patients with RA GDF-15 was associated to cIMT after 11 years of follow-up. GDF-15 should be a biomarker of interest in future research, to further understand its role in the accelerated atherogenesis in patients with RA.

Patients with rheumatoid arthritis (RA) have an increased prevalence and severity of atherosclerosis, and a corresponding increased risk of cardiovascular disease. The mechanisms causing this are not well elucidated, but both traditional cardiovascular risk factors and RA-associated factors have been associated with atherosclerosis and increased risk of cardiovascular events in patients with RA. Cardiovascular risk estimation based on traditional cardiovascular risk factors, often underestimates the risk in patients with RA. The aims of this thesis were to examine factors and biomarkers associated with atherosclerosis in patients with RA, and to evaluate an algorithm for cardiovascular risk estimation in patients with RA.

Methods Patients with early RA in the four northernmost counties of Sweden have since 1995 been included in a prospective study of both the progress of RA and comorbidities. Besides clinical data, radiographs, genetic markers and autoantibodies are registered. Paper I includes 665 patients aged 40-80 years from that cohort, in whom the 10-year risk of a first cardiovascular event was estimated with both Expanded Cardiovascular Risk Prediction Score in Rheumatoid Arthritis (ERS-RA), and the general population based ACC/AHA algorithm. The estimations were then compared to the actual outcomes. Paper II examines factors associated with coronary artery calcification (CAC) in 22 patients with long-standing RA. Papers III and IV use data from a cohort of patients <60 years of age at diagnosis of RA (n=79), in whom development of atherosclerosis has been prospectively followed since diagnosis of RA. This is a subset of patients from the larger cohort in paper I. Controls matched for age and sex (n=44) are examined as well. In paper III, phenotypes of T-cells and IgG-antibodies against cytomegalovirus (CMV) are analysed in relation to carotid intima-media thickness (IMT). In paper IV, bone mineral density and markers and regulators of bone metabolism are analysed in relation to IMT.

Results Cardiovascular risk estimation with the RA-specific algorithm ERS-RA is not superior to estimation with the ACC/AHA algorithm. Both algorithms underestimate the risk in patients with a high grade of inflammation and in patients with an estimated moderate risk. In patients with long-standing RA, presence of CAC is associated with inflammatory activity, both at time of examination and in earlier stages of RA. Presence of anti-CMV IgG antibodies and altered T-cells (both CD4+ and CD8+) lacking the co-stimulatory molecule CD28 (CD28null) are associated with a higher IMT, and patients IgG-positive for CMV have a rapid increase in IMT after onset of RA. Regulators of bone metabolism (sclerostin, osteoprotegerin and osteocalcin) are associated with a higher IMT in patients with RA.

Conclusion Cardiovascular risk estimation in patients with RA still needs to be improved. The fact that CMV-positivity, altered populations of T-cells and IMT all are associated, and that also regulators of bone metabolism reflect IMT, suggests that the pathogenesis of atherosclerosis in patients with RA is multifactorial.  This thesis provides knowledge of the accelerated development of atherosclerosis in RA and could possibly be relevant also in other chronic inflammatory diseases, where markers of accelerated atherosclerosis and increased cardiovascular risk are lacking.

Objectives: Patients with rheumatoid arthritis (RA) have an accelerated progression of atherosclerosis. The aims of this study were to study the associations between subsets of T-cells, subclinical atherosclerosis assessed by intima-media thickness (IMT) and serological status for CMV in patients with RA.

Methods: Patients with new-onset RA (n=79), aged ≤60 years at diagnosis, were included in a prospective study of atherosclerosis. Controls matched for age and sex were also included (n=44). Ultrasound measurement of IMT in the common carotid artery was undertaken at inclusion (T0), after 1.5 years (T1.5) and after 11 years (T11). At T11, flow-cytometry analysis was undertaken to investigate subsets of T-cells. Serological analysis for CMV was undertaken from samples collected at T0.

Results: At T0, 66% of the patients and controls were CMV immunoglobulin G-positive. CMV-IgG positive patients had a significantly more rapid increase in IMT at T1.5, compared with controls and CMV-IgG negative patients. CMV-IgG positive patients had a significantly higher percentage of T-cells lacking CD28 (both CD4+CD28null and CD8+CD28null T-cells) than CMV-IgG negative patients. Increased levels of CD4+CD28null and CD8+CD28null T-cells were significantly associated with IMT at T11, adjusted for systolic blood pressure. CX3CR1 was expressed in CD4+ and CD8+ CD28null T-cells, but CX3CR1 per se was not associated with increased IMT.

Conclusions: Presence of CMV IgG-antibodies in patients with RA is associated with altered T-cell-populations and an increased burden of atherosclerosis. A possible protective effect of antiviral treatment in CMV-positive patients with new-onset RA should be considered.

OBJECTIVE: Cardiovascular (CV) risk estimation calculators for the general population do not perform well in patients with rheumatoid arthritis (RA). An RA-specific risk calculator has been developed, but did not perform better than a risk calculator for the general population when validated in a heterogeneous multinational cohort.

METHODS: In a cohort of patients with new-onset RA from northern Sweden (n = 665), the risk of CV disease was estimated by the Expanded Cardiovascular Risk Prediction Score for Rheumatoid Arthritis (ERS-RA) and the American College of Cardiology/American Heart Association algorithm (ACC/AHA). The ACC/AHA estimation was analyzed, both as crude data and when adjusted according to the recommendations by the European League Against Rheumatism (ACC/AHA × 1.5). ERS-RA was calculated using 2 variants: 1 from patient and physician reports of hypertension (HTN) and hyperlipidemia [ERS-RA (reported)] and 1 from assessments of blood pressure (BP) and blood lipids [ERS-RA (measured)]. The estimations were compared with observed CV events.

RESULTS: All variants of risk calculators underestimated the CV risk. Discrimination was good for all risk calculators studied. Performance of all risk calculators was poorer in patients with a high grade of inflammation, whereas ACC/AHA × 1.5 performed best in the high-inflammatory patients. In those patients with an estimated risk of 5-15%, no risk calculator performed well.

CONCLUSION: ERS-RA underestimated the risk of a CV event in our cohort of patients, especially when risk estimations were based on patient or physician reports of HTN and hyperlipidemia instead of assessment of BP and blood lipids. The performance of ERS-RA was no better than that of ACC/AHA × 1.5, and neither performed well in high-inflammatory patients.

Objective. A long-term follow-up of patients with rheumatoid arthritis (RA) to evaluate factors related to coronary artery calcification (CAC). Methods. All 22 eligible patients (4 males/18 females, mean age 65 years, and RA-duration 30-36 years) from the original (baseline; n = 39) study of atherosclerosis were included. Inflammation, cardiovascular risk factors, and biomarkers were measured at baseline. At follow-up 13 years later, CAC was assessed by computed tomography (CT) and the grade of inflammation was measured. Multivariate analysis of differences between patients with low (0-10) and high CAC (>10) was done by orthogonal projection to latent structures (OPLS). Results. Ten patients had CAC 0-10 and 12 had >10 (range 18-1700). Patients with high CAC had significantly higher ESR (24.3 versus 9.9 mm/h) and swollen joint count (2 versus 0). The OPLS models discriminated between patients having high or low CAC. With only baseline variables, the sensitivity was 73% and the specificity 82%. The model that also included inflammatory variables from follow-up had a sensitivity of 89% and a specificity of 85%. Exclusion of baseline intima media thickness and plaque from the latter model modestly reduced the accuracy (sensitivity 80% and specificity 83%). Conclusions. CAC is related to inflammation in patients with RA.

OBJECTIVES:Patients with rheumatoid arthritis (RA) have an accelerated progression of atherosclerosis. The aim of this study was to examine the associations between subclinical atherosclerosis, assessed by intima-media thickness (IMT), and regulators of bone formation, markers of bone turnover and bone mineral density (BMD) in patients with RA.

METHODS:Patients with new-onset RA (n=79), aged ≤60 years at diagnosis, were consecutively included in a study of development of atherosclerosis. Ultrasound measurement of IMT of the common carotid artery was undertaken at inclusion (T0) and after 11 years (T11) (n=54). Bone turnover biomarkers were examined in samples collected at T0 and T11. BMD was assessed at T11.

RESULTS:In patients with RA, osteocalcin (OCN) and osteoprotegerin (OPG) measured at T11 were significantly associated with IMT at T11, adjusted for systolic blood pressure (SBP) and age. BMD at T11 and the bone turnover markers procollagen type 1 N-terminal propeptide (P1NP) and carboxy-terminal crosslinked C-terminal telopeptide (CTX) were not associated with IMT. OPG, OCN and sclerostin at T0 were significantly associated with IMT at T11, and OPG and OCN at T0 were associated with change in IMT from T0 to T11. The associations between IMT and bone biomarkers were stronger in patients with joint erosions at onset of RA, than in patients with non-erosive disease.

CONCLUSIONS:Atherosclerosis in patients with RA is associated with OPG and OCN, but not with BMD or markers reflecting ongoing bone turnover, indicating that atherosclerosis is not associated with bone turnover per se.