Forty percent of patients with psoriasis were found to have the metabolic syndrome in a study of a nationally representative sample of more than 6,500 adults.
The prevalence of the metabolic syndrome was about twice as high in psoriasis patients as in adults without psoriasis, even after adjustment for potential confounders such as age, sex, race/ethnicity, smoking status, and CRP levels, reported Dr. Thorvardur Jon Love of Brigham and Women's Hospital, Boston, and his associates.
“Based on these data, it is estimated that of the 6.6 million adults (age range 20–59 years) with psoriasis in the United States, 2.7 million have the metabolic syndrome, or nearly a million more individuals than would be expected from individuals without psoriasis,” they noted.
The study findings may partially explain why previous research has found increased risks of cardiovascular and metabolic morbidity and mortality in psoriasis patients. In particular, patients with severe psoriasis have been reported to be at an increased risk for MI, stroke, and cardiovascular mortality, and have been reported to die 3–4 years earlier than people without psoriasis, the investigators added.
The metabolic syndrome is characterized by abdominal obesity, hypertriglyceridemia, low HDL cholesterol levels, hypertension, and high fasting glucose levels. Recent research has pegged the incidence of the disorder at 15%–24% in the general U.S. population.
Noting that there has been only one previous study examining the relationship between psoriasis and the metabolic syndrome, and that until now there have been no population-based data on the issue, Dr. Love and his colleagues used data from the National Health and Nutrition Examination Survey (NHANES) 2003–2006 to assess the prevalence of the metabolic syndrome and its components in psoriasis.
The study included 2,456 adults (mean age 39 years) who did not have preexisting diabetes; 71 had psoriasis.
The prevalence of the metabolic syndrome was 40% among psoriasis patients, compared with 23% among patients without psoriasis. The odds ratio for patients with psoriasis to have the metabolic syndrome was 2.16 on univariate analysis and 1.96 after the data were adjusted to account for potential confounding factors.
When CRP levels were removed from the analysis to cancel out the potentially confounding effect of inflammation, odds ratios did not change materially, Dr. Love and his associates reported (Arch. Dermatol. 2010 [doi:10.1001/archdermatol.2010.370]).
“When we applied these data to the 2008 U.S. census population estimate, 6.6 million (95% CI, 4.8-8.3) individuals aged 20–59 years were estimated to have psoriasis in the United States, and 2.7 million (95% CI, 1.6-3.6) of these individuals with psoriasis were estimated to have the metabolic syndrome, an excess of 1 million patients compared with the expected value among individuals without psoriasis,” they noted.
The most common feature of the metabolic syndrome to be found among psoriasis patients was abdominal obesity, present in 63%. Hypertriglyceridemia and low HDL levels also were common.
These findings indicate that “a diagnosis of psoriasis should trigger a high clinical suspicion [of] and investigation for a potential coexistence of the metabolic syndrome. If present, the syndrome needs to be recognized as a potentially more life-threatening factor than psoriasis given the serious associated complications,” Dr. Love and his colleagues wrote.
This association also should be considered when choosing therapy for psoriasis. “For example, tumor necrosis factor blockers may decrease insulin resistance,” they added.
This study was supported in part by the National Institutes of Health, the Psoriasis Foundation, and the National Heart, Lung, and Blood Institute. One of Dr. Love's associates reported ties to Amgen, Abbott, Celgene, Centocor, Pfizer, and Novartis.