Link between psoriasis and diabetes and atherosclerosis

Apr 19 2007

Psoriasis is a chronic skin condition characterized by thick, red, scaly plaques that itch and sometimes bleed, causing considerable discomfort and emotional stress for patients.

In addition to the daily chore of dealing with the physical symptoms of this condition, new research suggests an association between psoriasis and two potentially serious medical conditions – diabetes and atherosclerosis, also known as hardening of the arteries.

For the 2 percent to 4 percent of the worldwide population affected by psoriasis, these findings could have a significant impact on their overall health, including the estimated 5.8 to 7.5 million Americans affected by the condition.

In the report entitled, “The association between psoriasis, diabetes mellitus, and atherosclerosis in Israel: A case-control study,” published in the April 2007 issue of the Journal of the American Academy of Dermatology , dermatologist Michael David, MD, Dermatology Department at Rabin Medical Center, Tel Aviv, Israel, and his colleagues found a higher occurrence of diabetes and atherosclerosis in psoriasis patients compared to patients without psoriasis.

“Previous reports have demonstrated an association between psoriasis and other diseases, including heart failure and diabetes,” said Dr. David. “Our study was designed to determine if such an association existed with psoriasis patients in Israel, if so, what subset of this patient population was most affected.”

The retrospective case-control study included 46,095 patients with psoriasis (identified as case patients) and 1,579,037 patients without psoriasis (identified as control patients) from the patient database of Maccabi Healthcare Services (MHS), the second largest managed care organization in Israel. Case patients were defined as having psoriasis when there was at least one documented diagnosis of psoriasis in the medical records between the years 1997 and 2004; the control group consisted of all MHS patients without a diagnosis of psoriasis during that time period.

Patients with diabetes and atherosclerosis were identified using the MHS diabetes and cardiovascular registries, and the proportion of diabetes and atherosclerosis among the case and control groups was analyzed by Dr. David and his team of researchers.

“When we compared the age-adjusted proportion of diabetes and atherosclerosis between patients with psoriasis and those patients in the control group, we found that the proportion of both medical conditions was significantly higher in psoriasis patients vs. the control group,” said Dr. David. “Examining the data among the psoriasis patients by age and gender, we also found several interesting associations.”

Specifically, the researchers noted that the association between diabetes and psoriasis was more prominent in women compared to men and in patients between the ages of 35 and 55. Similarly, the association between atherosclerosis and psoriasis was highest among women as compared with men and in patients between the ages of 35 and 55, and 65 and 75.

In addition, in patients with psoriasis, data analysis showed an association between diabetes and the overuse of extremely potent topical steroids or certain systemic medications for psoriasis. The researchers suggested that these observations could indicate that the prevalence of diabetes among psoriasis patients increases with the severity of psoriasis.

An association also was observed between the prevalence of atherosclerosis and the use of phototherapy, the medical light treatment administered by dermatologists for psoriasis. The researchers noted that it is possible that phototherapy is a marker for psoriasis severity rather than being the cause of atherosclerosis. Another possible explanation they offered is that phototherapy may be chosen as the treatment of choice for severe psoriasis patients who suffer from atherosclerosis rather than treating these patients with systemic medications.

“It is important to emphasize that while our study showed an association between psoriasis, diabetes and atherosclerosis, we did not determine the cause of this association or why there was a higher risk of both conditions in women and certain age groups,” added Dr. David. “Our data raise the question as to whether treatments for psoriasis predispose patients for developing diabetes or atherosclerosis, or if previous reports of a higher prevalence of both smoking and obesity among patients with severe psoriasis can explain this association. Regardless of the cause, this association has a major impact on public health issues and should be addressed in the management of all patients with psoriasis.”