Obesity
Dr. Ogdie was lead author of a national CORRONA Registry study which concluded that obese patients with PsA were only half as likely to achieve remission on a tumor necrosis factor (TNF) inhibitor, compared with nonobese patients. She believes the same holds true for all other types of therapy: Across the board, obesity is associated with a poor response. And obesity is much more common in PsA patients than the general population in every age group. Moreover, obesity is associated with risk factors for cardiovascular disease and is associated with fatty liver disease, two other major comorbid conditions in the PsA population.
The CORRONA Registry findings are supportive of an earlier Italian prospective, observational study of 135 obese and an equal number of normal-weight PsA patients, all of whom started on a TNF inhibitor and were followed for 24 months. In a multivariate-adjusted analysis, obesity was independently associated with a 390% higher risk of not achieving minimal disease activity.
The same Italian group subsequently conducted a prospective dietary intervention study in 138 overweight or obese patients with PsA starting anti-TNF therapy. A total of 59% of participants randomized to either of the two dietary interventions experienced at least a 5% weight loss at 6 months. The key study finding: Compared with the subjects with less than 5% weight loss, those with 5%-10% weight loss were 275% more likely to achieve minimal disease activity at 6 months, and in those with greater than 10% weight loss the likelihood of attaining minimal disease activity increased by 567%.
“We’re talking about a disease where treatments tested in clinical trials have odds ratios in the 1.2 range, compared with other therapies, so this is a really striking difference,” she observed.
Several studies have demonstrated that obesity in psoriasis patients is a risk factor for developing PsA. Recently, U.K. investigators took things a step further, reporting in a huge observational study that obese or overweight psoriasis patients who reduced their body mass index over a 10-year period had a corresponding reduction in the risk of developing PsA, compared with overweight or obese psoriasis patients whose BMI remained steady over the same period.
What’s needed now is access to programs to help patients with PsA lose weight. Health insurers are often unwilling to provide coverage. “We have a really tough time getting the patients in to see a nutritionist unless they’re willing to pay out of pocket,” Dr. Ogdie said.
Physical activity is an important element in successful weight loss. It also is recommended in practice guidelines for patients with inflammatory arthritis because of its salutary effects on disease activity scores, pain and stiffness, sleep, and quality of life. But a recent survey conducted by Dr. Ogdie and coworkers concluded that patients with PsA and other forms of inflammatory arthritis don’t receive much exercise guidance from their rheumatologists. About 60% of subjects were inactive. Those who were physically active typically engaged in aerobic exercise but were much less likely to do the other guideline-recommended forms of exercise, namely flexibility, balance, and resistance training. The patients’ report of low engagement of their physicians “suggests an opportunity for more prescriptive exercise discussions,” according to the investigators.
Diabetes, a critical risk factor for cardiovascular disease, occurs at an increased incidence in PsA. This was demonstrated in a U.K. cohort study coauthored by Dr. Ogdie. The study, which included nearly 4,200 individuals with PsA, concluded that they had a 43% greater incidence of diabetes than the general population in an analysis adjusted for body mass index, smoking, alcohol use, and demographics.
New-onset diabetes can be readily picked up by rheumatologists based upon the laboratory work they often order at patient office visits, or during their review of symptoms, she noted, and added that the U.S. Preventive Services Task Force recommends ordering a hemoglobin A1c test every 3 years.
Dr. Ogdie reported receiving research grants and/or consulting fees from numerous pharmaceutical companies. Her research is also funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases, the Rheumatology Research Foundation, and the National Psoriasis Foundation.