Severity of Skin Symptoms Key Factor in the Quality of Life of People with Psoriatic Arthritis

As patients with psoriatic arthritis know too well, they experience significantly poorer health-related quality of life (QoL) than the general population.

In fact, even though they have less their overall joint disease is less severe than patients with rheumatoid arthritis, psoriatic arthritis patients have similar levels of QoL as patients with rheumatoid arthritis, say the authors of a study recently published in Rheumatology and Therapy.

The QoL level of people with psoriatic arthritis can often be traced back to the skin manifestations of the disease. “Greater skin severity is associated with worse patient reported outcomes, including lower physical functioning, more patient-reported pain and fatigue, and a worse QoL," wrote William Tillett, M.D., and his colleagues. Tillett is a consultant rheumatologist at the Royal National Hospital for Rheumatic Diseases and senior lecturer in the department of pharmacy and pharmacology at the University of Bath in England.

The researchers set out to assess and quantify the burden of both joint and skin problems versus joint-only symptoms in psoriatic arthritis patients using a cross-sectional study of patients across nine countries. They collected patient- and physician-reported data from about 3,200 patients.

William Tillett, M.D.

Patient-reported outcomes included perceptions of symptom importance. The researchers also used standard questionnaires for measuring the impact of psoriatic arthritis and impairment of work and activity levels.

They found that patients with joint and skin involvement had higher mean tender and swollen joint counts (5.2 and 4.8) than patients who were joint-only (2.0 and 1.5). Significantly more patients with active joint and skin symptoms (39%) experienced a flare (currently or within the last year), compared with joint-only patients (23.2%).

When asked to prioritize the burden of symptoms, 61.6% of patients prioritized joints while 38.4% said skin was the priority. “Patients with joint and skin involvement reported significantly worse QoL, work productivity, and activity impairment than joint-only patients,” wrote Tillett and his colleagues.

In addition, 41.4% of patients experienced anxiety and depression — 62.4% of those patients said that both joint and skin symptoms were the cause.

“Worse outcomes were seen in patients with ‘joint and skin’ involvement compared with ‘joint-only’ diagnoses while increased skin severity within the ‘joint and skin’ cohort of patients was accompanied by a further decline in health status,” Tillett wrote.

As might be expected, there was also a decline in health status, QoL and work activity as the number of affected joints increased in the joint-only patient population.

In ‘joint and skin’ patients, worse skin symptoms had a greater adverse impact on QoL-related health status, disability, and WPAI-related outcomes compared with those with milder or less severe skin symptoms, Tillett and his co-investigators noted.

“Severe skin symptoms and additional number of affected joints clearly have a detrimental impact on outcomes in the respective patient populations. There is some evidence to suggest that greater skin severity in the ‘joint and skin’ group was associated with worse outcomes compared with greater number of joints affected in the ‘joint-only’ group, although this was not a formalized comparison,” they wrote.