Being overweight linked to significantly higher disease severity in psoriatic arthritis

The results of a study presented today at the Annual European Congress of Rheumatology (EULAR 2019) demonstrate significant correlation between body mass index (BMI) and disease severity in psoriatic arthritis.

Psoriatic arthritis is a chronic inflammatory disease that affects the skin and joints, causing pain and disability. The disease often causes swelling of the fingers and toes, mainly because of joint inflammation. Although psoriatic arthritis has been associated with an enhanced prevalence of obesity and being overweight, few studies have assessed the relationship between weight and the severity of disease in these patients.

Results of this study demonstrate BMI is independently correlated to disease activity (p=0.026), patient-perceived disease impact (p<0.0001), and disability (p<0.0001). In patients with PsA classified as obese or non-obese, disease activity measure cDAPSA (range 0-154) was 33.4 vs. 27.7, patient-perceived disease impact measure PsAID-12* (range 0-10) was 6.3 vs. 5.3, and disability measure HAQ-DI* (range 0-3) was 1.36 vs. 1.03 respectively.

"Our results highlight the impact of obesity and need for lifestyle-directed approaches to manage weight in psoriatic arthritis in parallel to joint and skin focused treatments," said Dr. Stefan Siebert, Clinical Senior Lecturer in Inflammation and Rheumatology, University of Glasgow, United Kingdom.

The study included 917 patients across eight European countries as part of the PsABio study, an ongoing prospective observational study evaluating patients with PsA receiving ustekinumab or tumour necrosis factor inhibitors. Data were collected on disease severity and impact, and analysed using multiple regression models adjusted for age, sex, smoking, body surface area, c-reactive protein, disease duration and biologic treatment.

"There is growing evidence describing how fat tissue acts as an active organ involved in metabolic and inflammatory disorders," said Professor John D. Isaacs, Chairperson of the Abstract Selection Committee, EULAR. "Furthermore, with fixed-dose drug regimens, as with self-injected biologics, obesity can reduce efficacy for pharmacokinetic reasons." These factors, alongside the global epidemic of overweight and obesity, makes research in this area of great relevance and interest."

Another study presented today at EULAR 2019 provides evidence for the adipokine, adiponectin, in predicting the development of rheumatoid arthritis in overweight subjects.

Adipokines are signalling molecules that are secreted by fat tissue and act in a similar way to hormones. Raised levels of adiponectin, a type of adipokine, have been shown in subjects with rheumatoid arthritis, however, results of this study suggest it could have a role in predicting the onset of disease.

"Early detection and management of rheumatoid arthritis is very important to improve disease outcomes in patients," said Cristina Maglio, MD, Ph.D., University of Gothenburg, Gothenburg, Sweden. "Our analysis suggests that serum adiponectin in overweight patients might have a role as a biomarker for early rheumatoid arthritis."

The analysis included two studies, the first included 82 subjects with obesity and available measurements of adiponectin before the development of rheumatoid arthritis and 410 matched controls and demonstrated a 10% increased risk of developing rheumatoid arthritis in those with raised serum adiponectin at baseline. The second study included 88 sex- and age-matched pairs and demonstrated a 20% increased risk, but only in those with a BMI greater than 25.4.

Finally, another interesting study presented today at EULAR 2019, looked at overweight and obesity in young patients with juvenile idiopathic arthritis (JIA).

Results found the rate of being overweight, and obesity in children and adolescents with JIA is comparative to the general population. However, further analysis revealed a number of factors are significantly associated with being overweight in the JIA group including increasing age (OR:1.06, 95% CI:1.04-1.09), male gender (OR:1.21, 95% CI:1.04-1.44), functional limitations (OR:1.29, 95% CI:1.04-1.59), therapy with biological DMARDs (OR:1.48, 95% CI:1.22-1.80), and systemic glucocorticoids (OR:1.40, 95% CI:1.14-1.71). The implications of these findings on the long-term outcome of JIA requires further study.