Early Diagnosis in Psoriatic Arthritis Is Often Missed

Dr. Paras Karmacharya

How to identify patients with psoriatic arthritis at an earlier stage was a popular theme of research presented at the annual meeting of the American College of Rheumatology on Friday November 6.

More than half of patients with psoriatic arthritis have to wait two or more years for a diagnosis, and time to diagnosis has not significantly improved over the last two decades, a study by Paras Karmacharya, M.D., from the Mayo Clinic, Rochester, Minn., and colleagues found.

Their findings come from an analysis of 162 patients diagnosed with psoriatic arthritis between 2000 and 2017. Median time from joint symptoms to diagnosis by a physician was 2.5 years, with 23% diagnosed at 6 months, 35% at one year and 45% at two years.

Younger patients and those with a higher BMI and enthesitis before diagnosis were more likely to experience a diagnostic delay of more than two years, while patients with sebopsoriasis were less likely to experience diagnostic delay. Radiographic damage may be associated with diagnostic delay, the researchers said, but did not achieve statistical significance in their study perhaps due to the small sample size.

Karmacharya and colleagues study highlights the need to find highlighting the need to find preclinical signs of psoriatic arthritis that will enable providers to identify and treat patients earlier.

Alexis Ogdie-Beatty, M.D., MSCE, of the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, and colleagues used administrative claims data on 13,661 patients diagnosed with psoriatic arthritis in an attempt to identify potential predictors of psoriatic arthritis in the six years prior to their diagnosis.

Each psoriatic arthritis patient was matched by age, sex, geographic location, insurance, and enrollment duration with two patients who did not have the condition.

Compared with controls, patients with psoriatic arthritis had an increased history of coding for arthritis and skin issues including osteoarthritis (48% vs 22%), rheumatoid arthritis (18% vs 2%), inflammatory polyarthropathy (18% vs 1%), and psoriasis (60% vs 2%). Psoriatic arthritis patients without a prior diagnosis of psoriasis were more likely to have a coding for other forms of arthritis.

Diagnoses of psoriasis, different types of arthritis, axial symptoms, and tendonitis/enthesitis steadily increased as the time of psoriatic arthritis diagnosis drew nearer, along with the frequency of rheumatology visits.

Another retrospective population-based study by Karmacharya and colleagues highlighted that transition from psoriasis to psoriatic arthritis was more likely to be delayed in patients with a family history of psoriasis and severe psoriasis.

The study was based on 157 patients with psoriatic arthritis, 51% of whom had concurrent psoriasis and 49% had psoriasis before a diagnosis of psoriatic arthritis. The researchers found that family history of psoriasis (odds ratio= 2.71; 95% CI 1.24, 5.90) and severe psoriasis (OR=1.96; 95% CI 1.26, 3.06) were more likely in patients who had a delay in transition from psoriasis to psoriatic arthritis than in those who had a concomitant diagnosis.

“Whether this difference is secondary to earlier detection of psoriasis in patients with a family history of psoriasis and severe psoriasis or a true phenotypic difference will require further studies,” the researchers said.

Two further studies used ultrasound to look for early signs of damage that may herald psoriatic arthritis.

In one Sayam Dubash, M.D., and colleagues at the University of Leeds, Leeds Institute for Rheumatic and Musculoskeletal Medicine, NIHR Leeds Biomedical Research Centre and Leeds Teaching Hospitals Trust, in the United Kingdom used ultrasound to show that dactylitis was a clinical indicator for an aggressive phenotype in psoriatic arthritis.

Their study included 177 patients with very early DMARD naïve psoriatic arthritis, of which 81 had dactylitis. Patients with dactylitis recorded significantly higher median differences in tender joint counts (p< 0.01), swollen joint counts (p< 0.001), C-reactive protein (p< 0.01), ultrasound synovitis (p< 0.01), and ultrasound defined erosions (p< 0.01). The metacarpophalangeal 2 and 5 joints were most prone to erosive damage.

“Longitudinal follow-up will determine if dactylitis represents poor prognosis at this very early disease stage,” the researchers said. “Dactylitis may be a useful discriminator for risk stratification in future psoriatic arthritis management strategies.”

In the other Gizem Ayan, M.D., from the division of rheumatology at the University of Ottawa, Canada and colleagues assessed 46 joints and 12 large entheses in 126 patients and showed a link between severity of the joint and entheses involvement.

Greyscale (GS) synovitis score for the joints was moderately correlated with the total enthesitis score (r=0.410, p< 0.001), and the Global Outcome Measure in Rheumatology in Clinical Trials-European League Against Rheumatism Synovitis Score (GLOESS) score also correlated with the total enthesitis score (r=0.400, p< 0.001).

There was a poor correlation between ultrasound assessments and findings on clinical examination, including between swollen joint counts and joint-ultrasound scores (r=0.298, p=0.001 for GLOESS), and between ultrasound entheseal damage scores and tender joint counts (r=0.217, p= 0.018) and swollen joint counts (r=0.326, p= p< 0.001).

The researchers said that their findings support the synovio-entheseal complex theory - that damage to entheses may activate the innate immune system and stimulate rapid development of bursitis.

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REFERENCES

ABSTRACT 0312. “Dactylitis Is Associated with Greater Disease Severity, Ultrasound Synovitis, and Erosive Damage, in Very Early DMARD Naïve Psoriatic Arthritis.” The annual meeting of the American College of Rheumatology. 9:00 AM, Friday, Nov. 6, 2020.

ABSTRACT 0311. “The Link Between Joints and Entheses in Psoriatic Arthritis: An Ultrasound Study Supporting the Synovio-entheseal Complex Theory.” The annual meeting of the American College of Rheumatology. 9:00 AM, Friday, Nov. 6, 2020.

ABSTRACT 0308. “Delay in Transition from Psoriasis to Psoriatic Arthritis: A Population Based Study.” The annual meeting of the American College of Rheumatology. 9:00 AM, Friday, Nov. 6, 2020.

ABSTRACT 0309. “Diagnostic Delay in Psoriatic Arthritis: A Population Based Study.” The annual meeting of the American College of Rheumatology. 9:00 AM, Friday, Nov. 6, 2020.

ABSTRACT 0307. “Longitudinal Analysis of the Patient Pathways to Diagnosis of Psoriatic Arthritis.” The annual meeting of the American College of Rheumatology. 9:00 AM, Friday, Nov. 6, 2020.