Objective. To investigate disease activity, treatment response, and drug survival, and predictors thereof, among Danish patients with psoriatic arthritis (PsA) receiving their first treatment series with a tumor necrosis factor ␣ (TNF␣) inhibitor. Results. Of 764 patients with PsA, 320 received adalimumab, 260 infliximab, and 184 etanercept. Median drug survival was 2.9 years, and 1-year and 2-year drug survival rates were 70% and 57%, respectively. Clinical parameters that showed improvement over 6 months were the C-reactive protein (CRP) level, Health Assessment Questionnaire score, and 28-joint Disease Activity Score. Male sex, CRP level >10 mg/liter, concomitant methotrexate use, and low patient health visual analog scale score at baseline were associated with longer drug survival. Improvement was achieved by 59%, 45%, 24%, and 54% of patients according to the ACR20, ACR50, ACR70 response criteria and EULAR good response, respectively. A CRP level >10 mg/liter was predictive of the improvement responses (odds ratio [OR] 2.6 for ACR20, OR 3.0 for ACR50, OR 3.6 for ACR70, and OR 2.2 for EULAR good response).Conclusion. In these patients with PsA treated with their first TNF␣ inhibitor in clinical practice, high drug adherence and responder rates were observed. Moreover, increased levels of CRP at baseline were associated with both good treatment responses and continued treatment, which may be of clinical value in selecting the patients most likely to benefit from treatment with TNF␣ inhibitors.

BackgroundCentral pain mechanisms may be prominent in subsets of patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA) and other spondyloarthritis (SpA). The painDETECT questionnaire (PDQ) identifies neuropathic pain features, which may act as a proxy for centrally mediated pain.The objectives were to quantify and characterize pain phenotypes (non-neuropathic vs. neuropathic features) among Danish arthritis patients using the PDQ, and to assess the association with on-going inflammation.MethodsThe PDQ was included onto the DANBIO touch screens at 22 departments of Rheumatology in Denmark for six months. Clinical data and patient reported outcomes were obtained from DANBIO. A PDQ-score >18 indicated neuropathic pain features, 13–18 unclear pain mechanism and <13 non-neuropathic pain.ResultsPain data (visual analogue scale, VAS) was available for 15,978 patients. 7,054 patients completed the PDQ (RA: 3,826, PsA: 1,180, SpA: 1,093). 52% of all patients and 63% of PDQ-completers had VAS pain score ≥ 30 mm. The distribution of the PDQ classification-groups (<13/ 13-18/ >18) were; RA: 56%/24%/20%. PsA: 45%/ 27%/ 28%. SpA: 55% / 24%/ 21%. More patients with PsA had PDQ score >18 compared to RA and SpA (p<0.001). For PDQ > 18 significantly higher scores were found for all patient reported outcomes and disease activity scores. No clinical difference in CRP or swollen joint count was found. Logistic regression showed increased odds for having VAS pain ≥39 mm (the median) for a PDQ-score >18 compared to <13 (OR = 10.4; 95%CI 8.6–12.5).ConclusionsMore than 50% of the Danish arthritis patients reported clinically significant pain. More than 20% of the PDQ-completers had indication of neuropathic pain features, which was related to a high pain-level. PDQ-score was associated with DAS28-CRP and VAS pain but not with indicators of peripheral inflammation (CRP and SJC). Thus, pain classification by PDQ may assist in mechanism-based pain treatment.

In patients initiating or intensifying medical treatment for their RA, non-nociceptive pain (PDQ score ≥ 13) is common. In these patients, the pain mechanisms result in increased disease activity scores on a non-inflammatory basis.