Health Update

Severe psoriasis appears to be a potent risk factor for stroke independent of the traditional stroke risk factors, a doctor said at an international investigative dermatology meeting.

She presented a case-control study drawn from the UK General Practice Database (GPRD) in which she found psoriasis was associated with an excess stroke risk amounting to one additional stroke per 530 patients per year.

A doctor from the University of Pennsylvania, Philadelphia said that given the prevalence of psoriasis worldwide, these numbers carry potentially significant impact on public health.

Psoriasis affects about 2.5% of the population worldwide, including an estimated 4.5 million US adults. Of these, 5% have severe disease as defined by a need for systemic or phototherapy.

She and her coinvestigators had previously shown psoriasis to be an independent risk factor for acute MI, also using the GPRD. But the relationship between psoriasis and stroke had never before been studied.

The GPRD is an extensive electronic medical record including more than 9 million UK patients in 450 primary care practices. It was reported that in 129,143 patients with mild psoriasis in 1987-2002 and 496,666 contemporaneous controls without psoriasis, along with 3,603 patients with severe psoriasis and 14,330 separate controls, the mean follow-up was about 4 years.

As found in other studies, patients with severe psoriasis had higher rates of obesity and smoking than did controls, while rates of these and other traditional cardiovascular risk factors were similar in patients with mild psoriasis and in controls.

After adjustment for the major stroke risk factors, diabetes, hyperlipidemia, smoking, obesity, hypertension, age and gender — patients with mild psoriasis were found to have a statistically significant 6% per year increased relative risk of stroke. In contrast, the stroke risk in patients with severe psoriasis was increased by 43% per year, compared with matched controls.

The attributes risk of stroke in patients with mild psoriasis was 2.4 strokes per 10,000 person-years; with severe psoriasis it was 19 strokes per 10,000 person-years.

A caveat: a data audit suggested up to 15% of patients categorized in the GPRD as having mild psoriasis may actually have had moderate disease. If so, truly mild psoriasis may not be associated with any significant excess in strokes.

The working hypothesis is that the link between psoriasis and stroke, and MI as well — lies in Th1/Th17-mediated systemic inflammation, a prominent shared feature. Discussed at the meeting, sponsored by the European Society for Investigative Dermatology.

To examine the possibility that the excess stroke risk seen in severe psoriasis was a function of toxicities of treatments for the disease rather than being intrinsic to severe psoriasis itself, the investigators re-analyzed the data after excluding methorexate users or restricting the analysis to patients treated with oral retinoids. It didn’t have any significant impact on the results. Neither did exclusion of psoriatic arthritis patients.

Elsewhere at the conference, co-investigator presented an analysis of the rates of cardiovascular and peripheral vascular disease in the same study population. The rationale for this additional analysis was that MI and stroke are acute thrombotic events, and it would be informative to see if psoriasis is also associated with increased rates of chronic atherosclerotic diseases, coronary revascularization, carotid endarterectomy, and peripheral vascular intervention.

This proved to be the case, with the exception of peripheral vascular disease.

Source: Philippine Star