Weight Loss Improves Disease Management in Patients with Psoriatic Arthritis

July 1, 2014
Elise Oberliesen

Study results show that obese patients with psoriatic arthritis who were treated with tumor necrosis factor-alpha blockers who also lost at least 5 percent of their bodyweight from baseline were much more likely to achieve minimal disease activity.

According to the Journal of the American Medical Association, about a third of the adult population in the United States is obese while a growing number of youth aren’t far behind at a 17% obesity rate.

Obesity is a known risk factor associated with a myriad of diseases, including psoriatic arthritis. What the two conditions have in common—inflammation—is a concept helping to connect the dots for researchers interested in disease origin and treatment.

Obesity, while linked to heart disease and type 2 diabetes, is no longer considered a “lipid deposit disease” as previously thought, but rather is now thought of as an inflammatory response that sets off a cacophony of metabolic actions in the body, according to Viviane Zorzanelli Rocha and Eduardo J. Folco, whose research appeared in the 2011 Journal of Inflammation.

According to their research, “Obesity, long considered a condition characterized by the deposition of inert fat, is now recognized as a chronic and systemic inflammatory disease, where adipose tissue plays a crucial endocrine role through the production of numerous bioactive molecules, collectively known as adipokines.”

This change in thinking about obesity and potential for upregulating inflammation throughout the body has also lead to new treatment approaches.

“The understanding that inflammation plays a critical role in the pathogenesis of obesity-derived disorders has led to therapeutic approaches that target different points of the inflammatory network induced by obesity,” Rocha and Folco wrote.

Some of those therapies include use of “nonacetylated members of the group of salicylates” to treat inflammation and insulin resistance; diets supplemented with omega-3 polyunsaturated fatty acids; and TNF-α blockers (Etanercept) to treat inflammatory symptoms, though the authors noted mixed results.

Since research confirms that moderate weight loss improves many diseases like psoriatic arthritis, it is critical to incorporate weight loss into the treatment plan.

According to a study published in Annals of Rheumatic Disease, by Dr. Matteo Nicola, et al, from Federico II University, in Naples, Italy, losing ≥5% total body weight renders minimal disease activity (MDA) in people takingTNF-α blockers. Furthermore, those who lost more weight showed even better results when taking these medications.

“A higher rate of MDA achievement was found in subjects with 5—10% (OR=3.75, 95% CI 1.36 to 10.36, p=0.011) and in those with >10% (OR=6.67, 95% CI 2.41 to 18.41, p<0.001) weight loss in comparison with those with <5% weight loss,” the authors wrote.

The 138 study participants were divided into two dietary groups and randomly assigned. In the hypocaloric diet (HD group), people consumed <1500 kcal/day, 30 grams of fiber daily and no more than 35% fat. The second group, a free self-managed diet (FD group) placed very limited food restrictions on participants—such as eating only two fruits per day and two servings of olive oil plus more fish and vegetable consumption.

After six months under these two dietary protocols, study participants underwent the usual rheumatic evaluations‑‑tender joint count (TJC), swollen (SJC) joint count, tender entheseal count, Psoriasis Area Severity Index (PASI), etc‑‑to assess symptom and disease improvement.

“Patients were classified as having achieved minimal disease activity (MDA) only when fulfilling five of the following seven outcome measures at T1: TJC ≤1; SJC ≤1; PASI ≤1 or body surface area ≤3; VAS for pain ≤15; patient global disease activity VAS score of ≤20; HAQ ≤0.5 and tender entheseal points ≤1,” as reported in the study.

The research concluded that overweight patients with PSA report MDA with TNF-α blockers upon losing at least ≥5% body weight.