Specifically, the study found that more than half of the patients with psoriasis or psoriatic arthritis reported improvements in their disease following surgery.
Dr. Soumya Reddy, assistant professor of rheumatology and co-director of the Psoriatic Arthritis Center at NYU Langone Medical Center, reported the findings Nov. 8 at the American College of Rheumatology annual meeting in San Francisco.
“There have been studies showing that high BMI may be a risk factor for the development of incident psoriatic arthritis,” Dr. Reddy noted in an interview with Reuters Health. “This, in combination with case reports and a few small series that reported dramatic improvement in skin psoriasis after bariatric surgery is what initially prompted us to look into this. Some small studies have also shown that patients who lose some weight through diet in conjunction with starting a biologic achieve lower disease activity states.”
Dr. Reddy and colleagues did a chart review of roughly 9,000 patients who underwent bariatric surgery at their center from 2002 to 2013. They identified 86 patients who had psoriasis before surgery, including 21 with psoriatic arthritis, and compared their symptoms before and after undergoing bariatric surgery.
The average time from surgery was six years and the average excess weight loss was 46.2%
According to the researchers, 55% of patients with psoriasis and 62% of patients with psoriatic arthritis reported subjective improvements in their disease following weight-loss surgery.
Compared to before surgery, psoriasis disease severity rating scores on a zero-to-10 scale dropped from 5.6 to 4.4, and psoriatic arthritis scores fell from 6.4 to 4.5 one year after surgery, the researchers report.
Patients who lost the most excess weight one year after surgery showed the most improvement in their disease activity. Also, patients who had more severe disease at the time of surgery and were older at diagnosis also saw more improvements in disease.
Dr. Reddy told Reuters Health the mechanism for bariatric surgery’s putative effect on psoriasis and PsA is “probably multifactorial.”
“We know that adipose tissue produces pro-inflammatory mediators and cytokines that may help to drive inflammation. Some bariatric procedures also may alter gastric-produced hormones that may be playing a role. And in the case of psoriatic arthritis specifically there may be another role for just the reduction of biomechanical forces. Obviously profound weight loss will decrease the mechanical load on weight bearing joints and this may also reduce pain in weight bearing joints,” Dr. Reddy said.