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The metabolic syndrome and insulin resistance are not just common among patients with psoriatic arthritis, but both also correlate with the severity of the inflammatory musculoskeletal disease, according to a single-center, cross-sectional cohort study.
In the study of 283 consecutive white patients with longstanding psoriatic arthritis who attended a rheumatology clinic during a 1-year period, 44% were found to have the metabolic syndrome and 16% to have insulin resistance. "Our findings are novel and support our pretest hypothesis that the risk of metabolic syndrome and insulin resistance increases with the severity of underlying psoriatic arthritis, probably reflecting the increasing burden of inflammation," said Dr. Muhammad Haroon of the department of rheumatology and his associates at St. Vincent’s University Hospital, Dublin.
Psoriatic arthritis is known to be associated with heightened cardiovascular risk, and CV diseases are the leading causes of death in patients with psoriatic arthritis. Until now, however, the prevalences of these two major CV risk factors have not been well studied in patients with psoriatic arthritis. "We hypothesized, therefore, that there might be a greater burden of metabolic syndrome and insulin resistance in psoriatic arthritis, and consequently of cardiovascular diseases because of a greater inflammatory load," Dr. Haroon and his colleagues wrote (J. Rheumatol. 2014;41:1357-65).
The patients had psoriatic arthritis for a duration of at least 10 years (mean of 19 years), and just over half of the patients were women. Their mean age was 54.6 years.
A total of 124 patients (44%) were found to have the metabolic syndrome. "Even more alarming was the finding that about 50% of these newly diagnosed patients with metabolic syndrome had a combination of 4 or 5 of these risk features," the investigators said. In particular, elevated blood pressure (74%), greater waist circumference (56%), and elevated triglycerides (44%) were common among these psoriatic arthritis patients.
On multivariate analysis, metabolic syndrome was significantly associated with more severe disease, higher smoking pack-years, and worse EuroQol-5 dimension (EQ-5D). Metabolic syndrome was significantly associated with severe disease, even after adjustment for the presence of insulin resistance.
A total of 41 patients (16%) had insulin resistance of the 263 for whom insulin resistance data were available, which on multivariate analysis was significantly associated more severe disease, older age at the onset of psoriasis, and higher body-mass index, even after adjusting for the presence of metabolic syndrome.
Both the metabolic syndrome and insulin resistance were more frequent among patients with the most severe psoriatic arthritis, as measured by current and previous skin assessments; inflammatory markers; measures of disease activity; the number of deformed joints; and the presence of dactylitis, enthesitis, peripheral joint erosions, osteolysis, and sacroiliitis, the investigators said.
The study findings suggest, but do not establish, that "the higher burden of inflammatory arthritis or the combination of severe psoriatic disease features play major roles in the development of the metabolic syndrome and/or insulin resistance," Dr. Haroon and his associates said.
Their observations "can also help inform risk stratification" of patients with psoriatic arthritis, they added.
No disclosures were provided.
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