BUDAPEST — The last word on the relationship between psoriasis and cardiovascular disease may not be in, according to the results of a new study.
Contrary to earlier studies, psoriasis was found to not be an independent risk factor for hospitalization for ischemic heart disease in a large Dutch study, Dr. Marlies Wakkee reported at the annual congress of the European Society for Dermatological Research.
Even after subdividing the 15,820 Dutch psoriasis patients in the study into those who used only topical therapy versus patients with more severe disease—as defined by use of systemic therapies or hospitalization for psoriasis—the more severely affected patients did not have a higher rate of ischemic heart disease (IHD) hospitalization, said Dr. Wakkee of Erasmus University Medical Center, Rotterdam.
The same held true when the analysis was narrowed to hospitalization for acute myocardial infarction. The psoriasis patients, even those with more severe skin disease, did not have a greater rate of MI than controls, she added.
The study relied upon hospital and pharmacy linked databases covering 2.5 million Dutch patients. The 15,820 psoriasis patients and 27,577 nonpsoriatic controls (mean age 48 years) were followed for a mean of 6 years.
The IHD hospitalization rate was 611 cases per 100,000 person-years in psoriasis patients and 599 in controls. MI hospitalization rates were also similar: 234 per 100,000 person-years in psoriasis patients and 235 in controls.
At study entry, the psoriasis patients had slightly, but statistically significantly, higher rates of antihypertensive drug therapy, compared with controls (19.4% vs. 16.4%, respectively), lipid-lowering drugs (7.0% vs. 6.2%, respectively), and antidiabetic medications (4.4% vs. 3.6%, respectively). This was not surprising, said Dr. Wakkee, given that prior studies have shown the prevalence of metabolic syndrome to be elevated in psoriasis patients.
Psoriasis patients also had more hospitalizations for reasons other than psoriasis in the prior 6 months.
In a multivariate analysis adjusted for age, gender, medications, and hospitalizations in the prior 6 months, the relative risk of IHD hospitalization during 6 years of follow-up was 5% higher in psoriasis patients, and the MI hospitalization risk was 6% lower than in controls. These differences were far from statistical significance, she said.
Dr. Wakkee noted that her study findings are at odds with those of a much-publicized analysis of the U.K. General Practice Research Database (JAMA 2006;296:1735-41), which concluded that psoriasis patients had a small but significantly increased risk of MI. It is possible, she said, that the earlier finding was due to detection bias. This potential confounder could occur because psoriasis patients have greater consumption of health care, as shown by the Dutch patients' higher hospitalization rate.
Further muddying the waters, investigators at the University of Basel in Switzerland recently analyzed the U.K. General Practice Research Database and found no overall increased risk of MI, stroke, or transient ischemic attack in patients with recently diagnosed psoriasis, although there was a suggestion of a possible small absolute increase in MI risk in patients younger than age 60 with severe psoriasis (Br. J. Dermatol. 2009;160:1048-56). And no increase in cardiovascular mortality was identified in an earlier long-term follow-up study of PUVA-treated patients.
So the question remains: Is psoriasis as a systemic inflammatory state an independent risk factor for cardiovascular events, or does the increased risk, if present, result from psoriasis patients' increased prevalence of obesity, smoking, metabolic syndrome, and other cardiovascular risk factors?
Dr. Wakkee said the only way to resolve the controversy is to move beyond case-control studies and conduct a large, detailed, long-term prospective study. In the absence of definitive data, physicians will have to help patients minimize their risks.
In the absence of definitive data, physicians will have to help psoriasis patients minimize risks.
Source DR. WAKKEE