Inflammation and hypertension in rheumatoid arthritis.

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.