Weight Loss Augments Anti-TNF Therapy in Psoriatic Arthritis

Kate Johnson

June 09, 2012

June 9, 2012 (Berlin, Germany) — Overweight patients with psoriatic arthritis (PsA) who are starting anti–tumor necrosis factor (anti-TNF) treatment have a significantly better chance of greater treatment response and achieving minimal disease activity (MDA) if they lose weight, according to 2 studies reported here at the European League Against Rheumatism (EULAR) Congress 2012.

Although being overweight has been recognized as problematic in PsA, these new findings could provide extra motivation for patients to drop the pounds, said Laura Coates, MD, PhD, a researcher at the University of Leeds in the United Kingdom, who was the moderator of the session in which the research was presented.

"We know obesity and metabolic syndrome cause major problems for patients, but nobody has ever shown that weight loss can make a difference," she told Medscape Medical News.

The studies, both presented by Matteo Nicola Dario Di Minno, MD, from Frederico II University in Naples, Italy, prospectively evaluated the influence of obesity on MDA in patients with PsA starting anti-TNF treatment (n = 135), and then examined the influence of a hypocaloric diet.

In the first study, 135 patients with PsA and a body mass index (BMI) greater than 30 kg/m2 were prospectively compared with 135 patients with PsA of normal weight for 2 years after initiation of anti-TNF therapy.

Patients were a mean of 52 years and were refractory to treatment with traditional disease-modifying anti-rheumatic drugs (DMARDs).

"Trying to persuade people to actually lose the weight is going to be difficult, but at least we have evidence to back us up now," Dr. Di Minno announced at the meeting.

After 1 year, 98 patients (36.3%) had achieved MDA. Among the patients not achieving this goal, a higher proportion were obese than normal weight (64% vs 25.5%; P < .001).

After adjusting for all the other variables, obesity was associated with a higher risk of not achieving MDA (hazard ratio [HR], 4.90; P < .001), and the risk increased with degree of obesity, reported Dr. Di Minno.

Specifically, obese patients with a BMI between 30 and 35 kg/m2 were less likely to achieve MDA compared with obese patients with a BMI below 30 kg/m2 (HR, 5.40 vs 3.98; P < .001).

Among the 98 patients who achieved MDA at 1 year, 82.7% sustained it through to 24 months; however, obesity increased the risk for relapse (HR, 2.04; P = .014).

The second study included a similar cohort of obese patients with PsA (BMI > 30 kg/m2) refractory to traditional DMARDs and about to initiate anti-TNF therapy.

Patients were randomly assigned to either a largely "Mediterranean" hypocaloric diet consisting of 1300 kcal, a 20% caloric restriction (n = 69), or a self-managed, "free" diet (controls) and were encouraged to exercise 5 times per week.

After 6 months of follow-up, the percentage of patients who had achieved MDA was not significantly different between groups (42.9% of the hypocaloric group and 34.9% of the self-managed group).

"Of course, this surprised us," said Dr. Di Minno. "This data confirmed the expected idea that only to prescribe a diet is not enough; it is necessary to have a successful diet," he told Medscape Medical News. "A diet is defined successful when the weight loss is greater than 5% (usually 5% to 10%)," he said, adding that almost 89% of the study group achieved a greater than 5% weight loss compared with only 28% of the free diet group, and none of the latter achieved a 10% weight loss.

Stratifying patients according to weight loss revealed that 42% of patients with a weight loss between 5% and 10% achieved MDA (HR, 2.05), and 59% of patients with a weight loss of more than 10% achieved MDA (HR, 4.79; P = .002), he said.

"It's a simple intervention in one sense, but probably one of the hardest," commented Dr. Coates in an interview with Medscape Medical News. "But at least we have evidence to back us up now. We can say look, there's evidence that [if you lose weight] you will do better, your arthritis will do better, and I think that's a better motivator than just the long-term overall view. To say in 3 months or 6 months your arthritis will be better is a quick and specific benefit that they can see."

Dr. Di Minno and Dr. Coates have disclosed no relevant financial relationships.

European League Against Rheumatism (EULAR) Congress 2012: Abstracts OP0162 and OP0163. Presented June 8, 2012.

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