By Neil Canavan
Berlin, Germany—A pair of complementary studies presented at the 2012 European League Against Rheumatism Congress of patients with psoriatic arthritis who have just started anti–tumor necrosis factor (TNF) therapy illustrate that (1) obesity is a negative predictor of achieving minimal disease activity, and (2) patients with psoriatic arthritis who are able to lose weight by adhering to a hypocaloric, fiber-enriched diet can reverse the negative disease outcomes associated with being overweight.
“A study presented at the 2009 meeting of the Society for Investigative Dermatology alerted us to the fact that patients with psoriatic arthritis have an increased prevalence of obesity,” said Matteo Nicola Dario Di Minno, MD, Regional Reference Centre for Coagulation Disorders, Rheumatology Research Unit, Psoriatic Arthritis Clinic, University of Naples Federico II, Italy, the lead investigator of both studies. His objectives in these 2 investigations were to firmly establish the link between obesity on poor treatment outcomes and whether weight loss alone could reverse that suspected correlation.
In the first study, Dr Di Minno and colleagues recorded the treatment outcomes for 135 obese (body mass index [BMI], >30 kg/m2) patients with psoriatic arthritis and 135 patients with normal weight who were used
as a control group. All patients were treated with anti-TNF agents and were followed for 24 months. Patients were evaluated at baseline, at 12 months, and at 24 months for achieving minimal disease activity.
After 12 months, 64% of the patients not achieving minimal disease activity were obese compared with 26% nonobese patients; beyond the defined obesity threshold, weight-associated outcomes worsened as patient BMI increased.
Among the 98 patients in the entire cohort who achieved minimal disease activity at 12 months, the obese patients were twice as likely to lose disease activity after 24 months.
An Apple a Day
The second study enrolled 138 obese patients with psoriatic arthritis. After all patients began receiving
anti-TNF therapy, 69 patients were maintained on a hypocaloric diet (intervention group), and the remaining 69 were allowed to self-manage their food intake. Patients were followed for 6 months.
Results showed that at follow-up, the hypocaloric-diet cohort was associated with significantly improved laboratory values for systemic inflammation (evidence of psoriatic arthritis) compared with the self-managed cohort, and that the prevalence of successful weight loss through dietary intervention showed a significantly higher prevalence in minimal disease activity compared with the patients who self-managed their food intake.
Overall, patients with psoriatic arthritis who were using a hypocaloric diet were almost 5 times as likely to achieve minimal disease activity as their more liberally eating counterparts. “The results of our study suggest that obese patients with psoriatic arthritis who stick to a hypocaloric diet have a greater chance of achieving treatment goals,” Dr Di Minno concluded.