Supplementary Material for: Spanish Validation of the GEPARD Questionnaire for the Detection of Psoriatic Arthritis in Argentinian Patients with Psoriasis

<b><i>Background/Objective:</i></b> Psoriatic arthritis (PsA) is preceded by psoriasis in approximately 80% of cases. Dermatologists are pivotal for early detection. It is important to have simple tools that allow the detection of PsA in patients with skin psoriasis. The aim of our study was to evaluate the performance of an adapted version of the GEPARD Questionnaire in Spanish in Argentinian patients with psoriasis. <b><i>Methods:</i></b> This is a cross-sectional study. A new Spanish (Argentinian) (GEPARDa) translated version of the original questionnaire (German) was developed and then tested as a diagnostic tool in patients with psoriasis, PsA, osteoarthritis associated to psoriasis, and osteoarthritis, all evaluated by rheumatologists who used the CASPAR criteria. <b><i>Results:</i></b> Eighty-three patients were included (55 [66.3%] women with a mean age of 50.7 years [SD 6.3]). Forty-four patients had PsA (29 [34.9%] patients had previous diagnosis of PsA, and 15 [18%] were newly diagnosed after referral by their dermatologists), and 39 patients were without PsA (18 [21.6%] patients had psoriasis without articular involvement, 6 [7.22%] had psoriasis associated with osteoarthritis, and 15 [18%] had osteoarthritis). An area under the curve of 0.9554 (SD 0.01; 95% CI 0.91–0.99) was calculated considering the CASPAR criteria as the gold standard. With a cutoff of ≥6 the questionnaire showed a sensitivity of 88.64%, a specificity of 89.74%, a positive likelihood ratio of 8.6, and a negative likelihood ratio of 0.12. <b><i>Conclusions:</i></b> The GEPARDa version has proven to be a diagnostic tool with excellent performance so that it can be considered a valid tool for the detection of PsA in Argentinian patients.

**背景与研究目标**：银屑病关节炎（Psoriatic Arthritis, PsA）约80%的病例继发于银屑病。皮肤科医师在该病的早期筛查中发挥关键作用，开发能够便捷检出皮肤银屑病患者合并银屑病关节炎的简易工具具有重要临床意义。本研究旨在评估西班牙语版改良GEPARD问卷在阿根廷银屑病患者中的诊断效能。

**研究方法**：本研究为横断面研究。我们首先将原始德文版GEPARD问卷翻译为阿根廷西班牙语版本（命名为GEPARDa），随后以经风湿病学家采用CASPAR标准（CASPAR Criteria）确诊的银屑病、银屑病关节炎、银屑病合并骨关节炎以及原发性骨关节炎患者为研究对象，对该问卷作为诊断工具的效能进行测试。

**研究结果**：本研究共纳入83例患者，其中女性55例（占比66.3%），平均年龄为50.7岁（标准差6.3）。44例患者确诊为银屑病关节炎：其中29例（34.9%）为既往确诊病例，15例（18%）经皮肤科医师转诊后首次确诊；剩余39例患者未合并银屑病关节炎：18例（21.6%）为单纯皮肤银屑病患者，6例（7.22%）为银屑病合并骨关节炎患者，15例（18%）为原发性骨关节炎患者。以CASPAR标准作为金标准，计算得到该问卷的曲线下面积为0.9554（标准差0.01；95%置信区间（95% CI）0.91–0.99）。当截断值设定为≥6时，该问卷的敏感度为88.64%，特异度为89.74%，阳性似然比为8.6，阴性似然比为0.12。

**研究结论**：阿根廷西班牙语版GEPARD问卷（GEPARDa）展现出优异的诊断效能，可作为检出阿根廷银屑病患者合并银屑病关节炎的有效工具。