Cipolletta Edoardo, Rozza Davide, Andres Mariano, Ottaviani Sébastien, Pascart Tristan, Calvo-Aranda Enrique, Chiarvetto Peralta Maria Victoria, Muto Pietro, Calabuig Irene, Gómez-Sabater Silvia, Caño Rocío, Léger Bastien, Pacaud Aurore, Moscioni Erica, Bruno Caterina, Caira Virginia, Gómez-González Claudia, Rosa Javier Eduardo, Nakafero Georgina, Filippucci Emilio, Abhishek Abhishek
Rheumatology Unit, Department of Clinical and Molecular Sciences, Polytechnic University of Marche, Ancona, Italy.
Academic Rheumatology, University of Nottingham, Nottingham, UK.
Rheumatology (Oxford). 2025 May 1;64(5):2609-2617. doi: 10.1093/rheumatology/keae681.
To develop and validate a patient-reported definition of acute calcium pyrophosphate (CPP) crystal arthritis in people with crystal-proven CPP deposition (CPPD) disease.
Consecutive patients with crystal-proven CPPD disease from seven centres across four countries were enrolled in a cross-sectional study. In each centre, patient-reported outcomes on the features of acute CPP crystal arthritis were collected. The expert opinion of an independent rheumatologist was the reference standard. We developed definitions based on multivariable logistic regression model with backward selection of predictors and classification and regression tree (CART) approaches.
Two hundred and forty-six patients [mean age 73.2 years (s.d. 10.7), 65.9% female] were enrolled. At the time of the assessment, acute CPP crystal arthritis was diagnosed in 96/246 (39.0%) participants.Patient-reported joint warmth, patient-reported joint swelling, time from pain onset to peak, and self-reported acute CPP crystal inflammatory arthritis were included in the multivariable logistic model. This model had good discrimination (optimism-adjusted c-index: 0.92; 95% CI: 0.89, 0.95) and calibration (optimism-adjusted calibration slope: 0.95; 95% CI: 0.71, 1.19; optimism-adjusted calibration-in-the-large: 0.005; 95% CI: -0.37, 0.37) in the internal validation. Probability threshold ≥0.53 had sensitivity of 0.83 (95% CI: 0.74, 0.90) and specificity of 0.86 (95% CI: 0.79, 0.91). Performances were similar in the internal-external cross-validation. The CART identified patient-reported acute CPP crystal inflammatory arthritis, followed by joint swelling and joint warmth as the most informative variables for ascertaining acute CPP crystal arthritis [sensitivity 0.83 (95% CI: 0.72, 0.91) and specificity 0.83 (95% CI: 0.74, 0.90)].
We developed and initially validated easy-to-use patient-reported definitions for acute CPP crystal arthritis for use in clinical trials and observational research in CPPD.
制定并验证一种由患者报告的、用于经晶体证实患有焦磷酸钙（CPP）沉积（CPPD）病患者的急性焦磷酸钙晶体关节炎定义。
来自四个国家七个中心的经晶体证实患有CPPD病的连续患者被纳入一项横断面研究。在每个中心，收集患者报告的急性CPP晶体关节炎特征的结果。一名独立风湿病专家的专家意见为参考标准。我们基于多变量逻辑回归模型并采用预测变量向后选择以及分类与回归树（CART）方法制定定义。
共纳入246例患者[平均年龄73.2岁（标准差10.7），65.9%为女性]。在评估时，96/246（39.0%）的参与者被诊断为急性CPP晶体关节炎。患者报告的关节发热、患者报告的关节肿胀、从疼痛发作到高峰的时间以及自我报告的急性CPP晶体炎性关节炎被纳入多变量逻辑模型。该模型在内部验证中具有良好的区分度（乐观度调整后的c指数：0.92；95%置信区间：0.89，0.95）和校准度（乐观度调整后的校准斜率：0.95；95%置信区间：0.71，1.19；乐观度调整后的总体校准度：0.005；95%置信区间：-0.37，0.37）。概率阈值≥0.53时，灵敏度为0.83（95%置信区间：0.74，0.90），特异度为0.86（95%置信区间：0.79，0.91）。在内部-外部交叉验证中表现相似。CART确定患者报告的急性CPP晶体炎性关节炎，其次是关节肿胀和关节发热是确定急性CPP晶体关节炎最具信息量的变量[灵敏度0.83（95%置信区间：0.72，0.91），特异度0.83（95%置信区间：0.74，0.90）]。
我们制定并初步验证了一种易于使用的、由患者报告的急性CPP晶体关节炎定义，可用于CPPD的临床试验和观察性研究。
