Usage of C-Reactive Protein Testing in the Diagnosis and Monitoring of Psoriatic Arthritis (PsA): Results from a Real-World Survey in the USA and Europe.

INTRODUCTION: C-reactive protein (CRP) is an important non-specific marker of both acute and chronic inflammation and can be elevated in patients with psoriatic arthritis (PsA). However, the use of CRP testing in the management of PsA can vary. This study investigated how CRP testing is implemented in real-world clinical practice for disease management of PsA. METHODS: A point-in-time survey of rheumatologists and dermatologists and their next six consulting patients with PsA was conducted in France, Germany, Italy, Spain, UK (EU5), and the USA between June and August 2018. Use of CRP testing was obtained by asking the physician to state (yes/no) whether CRP was used to aid PsA diagnosis and/or to monitor the patient's disease activity. The number of CRP tests conducted in the last 12 months for each patient enrolled was provided. RESULTS: Data were collected for 2270 patients (USA, n = 595; EU5, n = 1675). In the EU5, CRP testing was conducted to aid diagnosis in 78.7% of patients (vs. 43.4% in USA) and CRP was used to monitor disease activity in 72.0% (vs. 34.6% in USA). The majority (80.9%) of patients in the EU5 had at least one CRP test in the last 12 months compared to 42.9% in the USA. Patients treated by rheumatologists (vs. dermatologists) were at least 50% more likely to have CRP tested for monitoring purposes, this difference being most pronounced in the USA. In the EU5, CRP testing was conducted a mean ± standard deviation of 2.7 ± 1.7 times during the last 12 months, versus 2.0 ± 1.4 in the USA. CONCLUSIONS: CRP was more commonly used for the diagnosis and monitoring of PsA in Europe compared to the USA and was more commonly ordered by rheumatologists than dermatologists. In the absence of a better serum biomarker of inflammation, more data are needed to understand how CRP testing should be used in the diagnosis and management PsA.

Modifiable risk factors and the development of psoriatic arthritis in people with psoriasis.

BACKGROUND: Psoriatic arthritis (PsA) is a progressive and often destructive joint disease affecting approximately 20% of people with psoriasis. OBJECTIVES: To investigate associations between obesity, changes in body mass index (BMI), alcohol intake and smoking status and the development of PsA in people with psoriasis. METHODS: We undertook a cohort study involving incident cases of psoriasis identified from the U.K. Clinical Practice Research Datalink between 1998 and 2014. The associations between smoking, alcohol and BMI and development of PsA were assessed using generalized additive models. Additionally, the risks associated with a change in BMI during follow-up were investigated using distributed lag nonlinear models. RESULTS: We identified 90 189 incident cases of psoriasis (42% male, mean age 51 years), of whom 1409 had a subsequent record of PsA diagnosis. BMIs of 25·0-29·9, 30·0-34·9 and ≥ 35·0 kg m-2 were significantly associated with an increased risk of developing PsA compared with BMIs < 25·0 kg m-2 : adjusted odds ratios (95% confidence intervals) 1·79 (1·46-2·19), 2·10 (1·67-2·63) and 2·68 (2·09-3·43), respectively. Reducing BMI over a 10-year period (linearly) was associated with a reduction in the risk of developing PsA compared with BMI remaining constant over the same period. Increased risks of developing PsA were associated with moderate drinking but not with former or heavy drinking or with current or past smoking status. CONCLUSIONS: In this incident psoriasis cohort, increased BMI and moderate drinking, but not heavy drinking or smoking status, were associated with an increased risk of PsA in people with psoriasis. Importantly, we have shown that reducing weight may result in a reduction in the risk of developing PsA. What's already known about this topic? There is some evidence that increased body mass index is associated with an increased risk of developing psoriatic arthritis. There are conflicting results surrounding the relationship between smoking and the development of psoriatic arthritis among patients with psoriasis. What does this study add? Using a nonlinear and lagged effect of body mass index measured over time we have shown that reducing body mass index may be associated with a reduction in the risk of developing psoriatic arthritis. We have found no evidence that smoking alters the risk of developing psoriatic arthritis in patients with psoriasis.

Feasibility, reliability, and sensitivity to change of four radiographic scoring methods in patients with psoriatic arthritis.

OBJECTIVE: We set out to assess the feasibility, reliability, and sensitivity to change of 4 radiographic scoring methods in psoriatic arthritis (PsA). METHODS: Hand and feet radiographs from 50 patients with PsA were scored at 2 time points by 2 assessors with each of the following methods: modified Steinbrocker score, modified Sharp score (MSS), modified Sharp/van der Heijde score (SHS), and the Ratingen score for PsA. The radiographs of 10 patients were scored by both assessors to assess reliability using intraclass correlation coefficients (ICCs). Sensitivity to change was estimated using a standardized response mean (SRM) and smallest detectable change (SDC). RESULTS: The patients' mean ± SD age at baseline was 50 ± 12.1 years, the mean ± SD disease duration was 10 ± 8.4 years, and the mean ± SD followup period was 25 ± 9.6 months. Intrarater reliability was excellent for all methods (ICC >0.97). Interrater reliability was highest for the SHS (ICC 0.95-0.99). The percentage SDC for the Steinbrocker method, the Ratingen method, the MSS, and the SHS was 2.9%, 2.1%, 1.4%, and 1.2%, respectively, and the SRMs were 0.46, 0.44, 0.77, and 0.79, respectively. The mean time to score each of the Steinbrocker method, the Ratingen method, the MSS, and the SHS was 6.2, 10.5, 14.6, and 14.4 minutes, respectively. CONCLUSION: The SHS method was the most reliable and sensitive to change but took longer to perform. The Steinbrocker method is the most feasible but lacks the sensitivity of the SHS. The SDC of the Ratingen method is close to that of the SHS and MSS, but is quicker to perform.