Validating the Chinese Version of the Psoriasis Epidemiology Screening Tool and Early Arthritis for Psoriatic Patients Questionnaires
Psoriatic arthritis (PsA) is a chronic inflammatory musculoskeletal disorder frequently associated with psoriasis. Despite its clinical significance, a substantial proportion of psoriasis patients remain undiagnosed for PsA, leading to delayed treatment, accelerated joint damage, and irreversible functional impairment. Early detection is critical, as up to 80% of PsA cases develop skin manifestations before joint symptoms, positioning dermatologists as frontline identifiers of early PsA. To address this need, screening tools like the Early Arthritis for Psoriatic Patients (EARP) questionnaire and the Psoriasis Epidemiology Screening Tool (PEST) have been developed for rapid assessment. While the EARP questionnaire had previously been translated into Chinese, its diagnostic performance—including sensitivity, specificity, and optimal cut-off values—remained unvalidated in Chinese populations. This study aimed to rigorously evaluate both the EARP and PEST questionnaires in Chinese psoriasis patients, establish their diagnostic accuracy, and determine appropriate cut-off points to optimize early PsA detection.
Study Design and Participant Recruitment
The cross-sectional study recruited 733 participants with psoriasis through the Psoriasis Mutual Assistance Network (https://www.yxb365.com). Eligibility criteria required participants to be aged ≥18 years with a physician-confirmed psoriasis diagnosis. Exclusion criteria included prior PsA diagnosis or incomplete questionnaire responses. Among the initial cohort, 515 patients (70.3%) completed follow-up evaluations with rheumatologists within three months of questionnaire completion, forming the final analysis cohort. The study protocol received ethical approval from Peking Union Medical College Hospital (No. S-K 1299).
Participants completed an online survey capturing demographic data, psoriasis characteristics (e.g., disease duration, body surface area involvement), comorbidities (hypertension, diabetes, hyperlipidemia, gout), and treatment history (topical therapies, systemic agents, biologics). The survey incorporated the Chinese versions of the EARP and PEST questionnaires. The PEST questionnaire underwent rigorous translation and cross-cultural adaptation, while the EARP utilized a pre-existing Chinese translation.
Diagnostic Confirmation and Statistical Analysis
PsA diagnosis was confirmed by rheumatologists using standardized clinical and imaging criteria. Among the 515 patients evaluated, 40 (7.8%) received new PsA diagnoses, while 475 were classified as cutaneous-only psoriasis. Comparative analyses revealed PsA patients were older (mean age 44.0 ± 12.2 vs. 38.7 ± 12.4 years, P < 0.05) and had longer psoriasis duration (12.0 ± 9.9 vs. 8.6 ± 8.1 years, P < 0.05). Comorbidities like hypertension (27.5% vs. 18.5%), diabetes (12.5% vs. 5.3%), and hyperlipidemia (7.5% vs. 4.2%) were more prevalent in the PsA group, though differences lacked statistical significance. Biologic use was comparable between groups (PsA: 17.5%; psoriasis: 20.6%), potentially masking joint symptoms in some cases.
Univariate logistic regression identified age, psoriasis duration, diabetes, coronary heart disease, family history, and body surface area involvement as potential PsA predictors (P < 0.25). However, multivariate analysis found no independent predictors, highlighting the complexity of PsA risk stratification.
Diagnostic Performance of EARP and PEST Questionnaires
Receiver operating characteristic (ROC) curve analysis evaluated both tools against rheumatologist-confirmed diagnoses. The EARP questionnaire demonstrated superior performance, with an area under the curve (AUC) of 0.899 (95% CI: 0.853–0.945). At the established cut-off of ≥3, sensitivity was 77.5% and specificity 86.9%. In contrast, the PEST questionnaire achieved an AUC of 0.848 (95% CI: 0.788–0.908). At its original cut-off of ≥3, sensitivity was 52.5% with high specificity (93.1%). Lowering the PEST threshold to ≥2 improved sensitivity to 77.5% but reduced specificity to 78.9%.
Clinical Implications and Trade-offs
The EARP’s higher sensitivity at equivalent specificity suggests it may better balance early detection and referral burden in Chinese populations. However, both tools showed overlapping 95% CIs for AUCs, indicating comparable overall accuracy. The EARP’s design—focusing on peripheral joint symptoms, dactylitis, and enthesitis—likely contributed to its edge over the PEST, which omits axial involvement assessment. This limitation of the PEST could delay diagnosis in patients with isolated spinal or sacroiliac disease.
Adopting a lower PEST cut-off (≥2) increased sensitivity to match the EARP but escalated referral rates from 7.8% to 21.1%, straining healthcare resources. Given PsA’s high prevalence (7.8% in this cohort) and severe consequences of delayed diagnosis, the trade-off between sensitivity and referral burden may favor lower thresholds despite increased costs.
Limitations and Future Directions
The study’s online recruitment introduced potential selection bias, as participants may have shared survey links within PsA-aware networks, inflating symptom reporting. Additionally, 20.6% of cutaneous-only psoriasis patients used biologics, which might suppress subclinical joint inflammation and reduce questionnaire accuracy. The three-month gap between questionnaire completion and rheumatologist evaluation also risked missing interim PsA developments.
Future studies should prospectively validate these tools in unselected psoriasis cohorts, prioritize axial symptom assessment, and evaluate the impact of biologic therapies on screening performance. Integrating patient-reported outcomes with biomarker data could further enhance early detection algorithms.
Conclusion
This study provides robust validation of the Chinese EARP and PEST questionnaires as effective PsA screening tools. The EARP’s optimal balance of sensitivity (77.5%) and specificity (86.9%) at a cut-off of ≥3 supports its adoption in Chinese dermatology settings. While the PEST requires lower thresholds for comparable sensitivity, its increased referral burden may be justified by PsA’s debilitating prognosis. These findings empower dermatologists to identify early PsA, bridging critical gaps in multidisciplinary care for psoriasis patients.
doi.org/10.1097/CM9.0000000000001460
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