Psoriatic arthritis (PsA) is a complex inflammatory disease that can be challenging to diagnose due to its heterogeneous clinical features.^1,2 While diagnosis is commonly made through the identification of inflammatory musculoskeletal features in the presence of skin and/or nail psoriasis, no universal diagnostic criteria or tests are available for PsA.² As a result, there is a high prevalence of late and undiagnosed PsA which could lead to greater joint damage, radiological progression, and functional impairment in the long term.¹ To investigate whether a ‘window of opportunity’ for diagnosis exists in PsA and assess the patient characteristics associated with delayed diagnosis, a retrospective study was conducted.¹ The study revealed that achieving referral and diagnosis within one year was associated with optimal clinical outcomes.¹ Notably, female patients presenting with enthesitis, chronic back pain, or normal C-reactive protein (CRP) levels derived the greatest benefits from timely diagnosis within this specific timeframe.¹

PsA is an immune-mediated inflammatory disease characterized by a diverse range of musculoskeletal inflammation, including arthritis, enthesitis, spondylitis, and dactylitis.³ It typically manifests in individuals with psoriasis, affecting up to 30% of patients with the skin condition, particularly those with severe psoriasis or involvement of the nails or scalp.³ The chronic inflammation associated with PsA can result in joint damage and disability, emphasizing the importance of early diagnosis and treatment.³

In rheumatoid arthritis, initiating treatment within 12 weeks of symptom onset has demonstrated favorable outcomes, including higher rates of remission, reduced radiological progression and diminished functional impairment.¹ This study aimed to investigate whether a similar "window of opportunity" exists in PsA.¹ To accomplish this, the clinical and patient-reported outcomes of PsA patients with varying diagnostic delays were compared.¹ The diagnostic delay groups were categorized as follows: short delay (<12 weeks), intermediate delay (≥12 weeks and ≤1 year) and long delay (>1 year).¹

This study analyzed 708 newly diagnosed, DMARD-naïve Psoriatic Arthritis (PsA) patients from the Dutch southwest Early PsA cohoRt (DEPAR) between 2013 and 2020.¹ The patients were divided into three groups based on diagnostic delay: 19% with a short delay, 33% with an intermediate delay, and 47% with a long delay.¹ The overall median diagnostic delay was 10.8 months, comprising a median patient delay of 1.0 month and a median physician delay of 4.5 months.¹ Patients with enthesitis had the longest delay (median: 28.9 months), while those with polyarthritis and dactylitis had the shortest delays (median: 7.4 months).¹

During the 3-year follow-up, clinical outcomes were assessed using the Minimal Disease Activity (MDA) score and Disease Activity for Psoriatic Arthritis (DAPSA) score.¹ Various measures, including joint counts, psoriasis severity, enthesitis, dactylitis, and nail involvement, were evaluated.¹ Patient-reported outcomes (PROs) such as pain, functional ability, and disease impact were also recorded using questionnaires.¹

The study revealed that patients with a short delay (<12 weeks) had a higher likelihood of achieving MDA and DAPSA remission compared to those with a long delay (>1 year).¹ The short- and intermediate-delay groups exhibited slightly fewer tender joints during follow-up compared to the long-delay group.¹ In terms of PROs, the short-delay group experienced lower disease impact, less pain, and better general health compared to the long-delay group.¹ Female patients and those with enthesitis, chronic back pain, or normal CRP levels tended to have longer diagnostic delays.¹

In conclusion, timely referral and diagnosis within the first year of PsA onset are linked to improved clinical outcomes, indicating the existence of a significant opportunity for intervention.¹ The study highlights that reducing physician delay, particularly in cases involving females, patients with enthesitis, chronic back pain, or normal CRP levels, could yield the greatest benefits in terms of timely referral and diagnosis.¹