medwireNews: The metabolic syndrome is significantly more common in patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) than healthy individuals, researchers have found.

Overall, 43% of 91 AAV patients met the 2005 National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP-III) definition of the metabolic syndrome compared with just 25% of age- and gender-comparable healthy controls, regardless of current or accumulated prednisone use.

This included three or more of central obesity (men: waist ≥102 cm; women: waist ≥88 cm), diagnosis or treatment of hypertension (≥130/85 mmHg), elevated glucose (≥5.6 mmol/L), low high-density lipoprotein cholesterol (men: <1.0 mmol/L; women: <1.3 mmol/L), and high triglyceride levels (≥1.7 mmol/L), explain Jan Willem Cohen Tervaert (Maastricht University Medical Center, the Netherlands and co-authors.

Moreover, AAV patients with the metabolic syndrome had significantly higher median levels of the chronic inflammatory markers C-reactive protein (5.5 vs 3.0 mg/L) and neopterin (2.03 vs 1.78 ng/mL) than those without.

Patients with AAV and the metabolic syndrome were also more likely to have severe AAV disease - defined as affecting a critical organ or their life - than those with AAV alone (90 vs 63%), as well as a higher relapse rate, at 0.1 versus 0.0 relapses per year.

However, albumin levels, ANCA positivity at time of entry into study, ANCA persistence, and renal function measured using the Modification of Diet in Renal Disease formula were not significantly associated with the presence of the metabolic syndrome.

Writing in Rheumatology, the team proposes a two-way relationship where chronic low-grade inflammation associated with AAV drives development of the metabolic syndrome, while patients with the metabolic syndrome may be predisposed to AAV.

"We suggest that preventing or treating [the metabolic syndrome] might influence the disease course of AAV," Tervaert et al write.

Recognizing that cardiovascular disease is a major cause of morbidity among patients with AAV, they add: "If the importance of [the metabolic syndrome] can be confirmed in a prospective study, physicians should emphasize even more that their AAV patients should increase a healthy lifestyle."

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