Window of opportunity in psoriatic arthritis: the earlier the better?

Abstract

Objectives: To investigate whether there is a window of opportunity for psoriatic arthritis (PsA) patients and to assess which patient characteristics are associated with a longer diagnostic delay.

Methods: All newly diagnosed, disease-modifying antirheumatic drug-naïve PsA patients who participated in the Dutch southwest Early PsA cohoRt and had ≥3 years of follow-up were studied. First, total delay was calculated as the time period between symptom onset and PsA diagnosis made by a rheumatologist and then split into patient and physician delays. The total delay was categorised into short (<12 weeks), intermediate (12 weeks to 1 year) or long (>1 year). These groups were compared on clinical (Minimal Disease Activity (MDA) and Disease Activity index for PSoriatic Arthritis (DAPSA) remission) and patient-reported outcomes during 3 years follow-up.

Results: 708 PsA patients were studied of whom 136 (19%), 237 (33%) and 335 (47%) had a short, intermediate and long total delay, respectively. Patient delay was 1.0 month and physician delay was 4.5 months. Patients with a short delay were more likely to achieve MDA (OR 2.55, p=0.003) and DAPSA remission (OR 2.35,p=0.004) compared with PsA patients with a long delay. Patient-reported outcomes showed numerical but non-significant differences between the short and long delay groups. Female patients and those presenting with enthesitis, chronic back pain or normal C-reactive protein (CRP) had a longer delay.

Conclusions: In PsA, referral and diagnosis within 1 year is associated with better clinical outcomes, suggesting the presence of a window of opportunity. The most gain in referral could be obtained in physician delay and in females, patients with enthesitis, chronic back pain or normal CRP.

Keywords: Arthritis, Psoriatic; Outcome Assessment, Health Care; Patient Reported Outcome Measures.

Figure 1

Total diagnostic delay for different psoriatic arthritis phenotypes.Outliers are not shown for readability purposes.

Figure 2

Clinical outcomes for delay groups over 3 years of follow-up. (A) Probability of achieving MDA, (B) probability of achieving DAPSA remission, (C) mean swollen joint count and (D) mean tender joint count in psoriatic arthritis patients stratified for the delay groups short (<12 weeks), intermediate (12 weeks to 1 year) and long (>1 year). (A, B) The predicted response after correcting for age and sex, while figure (C, D) the mean with 95% CI. *A significant difference between the short delay group and the long delay group. **A significant difference between the intermediate delay group and the long delay group. DAPSA, Disease Activity index for PSoriatic Arthritis; MDA, Minimal Disease Activity.

Figure 3

Patient-reported outcomes for delay groups over 3 years of follow-up. (A) Functional ability measured with the HAQ, (B) disease impact measured with the PsAID-12, (C) mean general health and (D) mean pain in psoriatic arthritis patients stratified for the delay groups short (<12 weeks), intermediate (12 weeks to 1 year) and long (>1 year). (A, B) The predicted response after correcting for age and sex, while figure (C, D) the mean with 95% CI. *A significant difference between the short delay group and the long delay group. ***A significant difference between the short delay group and the intermediate delay group. HAQ, Health Assessment Questionnaire; PsAID-12, Psoriatic Arthritis Impact of Disease; VAS, Visual Analogue Scale.