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Hypertension is highly prevalent in patients with rheumatoid arthritis (RA). In other populations, high sodium (Na + ) and low potassium (K + ) intake are associated with an increased risk of hypertension, and in animal models, a high salt intake exacerbated arthritis. Patients with RA have many comorbidities associated with salt sensitivity, but their salt intake and its relationship to blood pressure and inflammation is unknown. Using the Kawasaki formula, Na + and K + urinary excretion (reflecting intake) was estimated in 166 patients with RA and 92 controls, frequency matched for age, sex, and race. Inflammatory markers and disease activity were measured in RA patients. We tested the associations between blood pressure and Na + and K + excretion. Estimated 24-h Na + excretion was similarly high in both RA (median [IQR] 5.1 g, [3.9-6.6 g]) and controls (4.9 g, [4.0-6.5 g]), p = 0.9, despite higher rates of hypertension in RA (54 vs. 39%, p = 0.03). The Na + :K + excretion ratio was significantly higher in RA (2.0 [1.6-2.4]) vs. 1.7 [1.5-2.1]), p = 0.02] compared to controls. In RA, a lower K + excretion was inversely correlated with diastolic blood pressure (adjusted β = - 1.79, p = 0.04). There was no significant association between Na + or K + excretion and inflammatory markers. Despite a similar Na + excretion, patients with RA had higher rates of hypertension than controls, a finding compatible with increased salt sensitivity. Patients with RA had a lower Na + :K + excretion ratio than controls, and lower K + excretion was associated with higher diastolic blood pressure in RA.

Objective: Hypertension (HTN), a common modifiable cardiovascular risk factor, is more common in patients with rheumatoid arthritis (RA), but the underlying mechanisms are unclear. We examined the hypothesis that mediators of inflammation and markers of cardiovascular risk are associated with HTN in RA., Methods: We compared measures of inflammation [serum C-reactive protein (CRP), tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), homocysteine, and leptin concentrations] and insulin resistance [homeostasis model assessment index (HOMA)] in RA patients with (n = 90) and without HTN (n = 79). HTN was defined as blood pressure ≥ 140/90 mm Hg or treatment with antihypertensive therapy. The independent association of markers of interest with HTN was examined using multivariable logistic regression., Results: Patients with HTN were significantly older and had longer disease duration than those without HTN (both p < 0.001). Concentrations of homocysteine [11.1 (8.5-13.5) μmol/l vs 9.3 (7.8-11.0) μmol/l] were significantly higher in patients with HTN (p < 0.001). After adjustment for age, sex, race, smoking, body mass index, and corticosteroid and nonsteroidal antiinflammatory drugs (NSAID) use, increased concentrations of homocysteine (OR 2.9, 95% CI: 1.5-5.5, p = 0.001), and leptin (OR 2.0, 95% CI: 1.0-3.8, p = 0.046) were significantly associated with HTN, but the 28-joint Disease Activity Score, IL-6, CRP, TNF-α, and HOMA index were not (all p > 0.05)., Conclusion: HTN in patients with RA is not associated with generalized systemic inflammation or insulin resistance, but is associated with increasing concentrations of homocysteine and leptin. The pathogenesis of HTN in RA may involve pathways more regularly associated with fat and vascular homeostasis.

Objective: Insulin resistance is increased by inflammation, but the mechanisms are unclear. The present study was undertaken to test the hypothesis that decreased insulin sensitivity is differentially associated with mediators of inflammation by studying 2 chronic inflammatory diseases of different pathogenesis, systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA)., Methods: We measured fasting insulin, glucose, and lipid levels, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor alpha (TNFalpha), and coronary artery calcification in 103 patients with SLE and in 124 patients with RA. Insulin sensitivity was measured using the homeostasis model assessment (HOMA) index., Results: The HOMA value was higher in RA patients (median 2.05 [interquartile range (IQR) 1.05-3.54]) than in SLE patients (1.40 [0.78-2.59]) (P = 0.007). CRP and ESR did not differ significantly in RA and SLE patients. Body mass index (BMI) was significantly correlated with the HOMA index in both RA (rho = 0.20) and SLE (rho = 0.54), independently of age, sex, race, and current use of corticosteroids. In RA patients, the HOMA index was also significantly positively correlated with IL-6 (rho = 0.63), TNFalpha (rho = 0.50), CRP (rho = 0.29), ESR (rho = 0.26), coronary calcification (rho = 0.26), and Disease Activity Score in 28 joints (rho = 0.21); associations adjusted for age, sex, race, BMI, and current use of corticosteroids remained significant (P < 0.05). In SLE patients, the HOMA index was also significantly correlated with ESR (rho = 0.35) and CRP (rho = 0.25), but not with other variables. The association between the ESR and the HOMA value in patients with SLE remained significant after adjustment for confounding covariates (P = 0.008). In multivariable models, the major contributing factors to the HOMA index were the BMI in SLE patients, and IL-6 and TNFalpha levels in RA patients., Conclusion: The pathogenesis of insulin resistance and its contribution to atherogenesis varies in different inflammatory settings.

Abstract: Osteoprotegerin (OPG), a soluble decoy receptor for receptor activator of nuclear factor κB ligand, is implicated in the pathogenesis of atherosclerosis. Patients with rheumatoid arthritis (RA) have inflammation and increased atherosclerosis. We examined the hypothesis that OPG concentrations are increased in patients with RA and are associated with coronary-artery atherosclerosis. Serum OPG concentrations were measured by ELISA and coronary-artery calcification by electron-beam computer tomography in 157 patients with RA and 87 control subjects. OPG concentrations were higher in patients with long-standing RA (n =67) [median (interquartile range)]: [1895 (1337–2847) pg/mL, and early RA (n =90): [1340 (1021–1652) pg/mL, than controls 1068 (692–1434) pg/mL; (p <0.001)]. In patients with RA, OPG concentrations were associated with erythrocyte sedimentation rate (p <0.001), homocysteine (p =0.001), disease duration (p =0.02), coronary calcium score (p =0.03), and cumulative dose of corticosteroids (p =0.04) after adjustment for age and sex. In patients with long-standing RA, OPG was associated with coronary-artery calcification independently of cardiovascular risk factors and disease activity [OR for every increase in 500pg/mL of OPG=2.22 (1.43–3.34), p <0.001]. In conclusion, OPG concentrations are increased in patients with RA and are associated with inflammation. In patients with long-standing disease, OPG is independently associated with coronary-artery calcification. [Copyright &y& Elsevier]