Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway
Division of Rheumatology, Department of Medicine, Hospital of Southern Norway Trust, Kristiansand, Norway.
Ann Rheum Dis. 2018 Dec;77(12):1736-1741. doi: 10.1136/annrheumdis-2018-213463. Epub 2018 Sep 20.
To test the psychometric performance of a modified Disease Activity index for PSoriatic Arthritis (DAPSA) using 28 instead of 66 swollen/68 tender joint counts (SJC/TJC).
We included patients with psoriatic arthritis (PsA) from the Danish national quality registry DANBIO, divided into examination (n=3157 patients, 23987 visits) and validation cohorts (n=3154 patients, 24160 visits). We defined DAPSA28 = (28TJC × conversion factor) + (28SJC × conversion factor) + patient global (0-10VAS) + pain (0-10VAS) + C reactive protein (CRP) (mg/dL). Identification of the conversion factors was performed by generalised estimating equations in the examination cohort and evaluation of in the validation cohort.
We estimated DAPSA28 = (28TJC × 1.6) + (28SJC × 1.6) + patient global (0-10VAS) + pain (0-10VAS) + CRP (mg/dL). DAPSA/DAPSA28 had comparable discriminative power expressed as standardised mean difference (DAPSA, 0.90; DAPSA28, 0.93) to distinguish between patients in high and low disease activity. Kappa with quadratic weighting of DAPSA/DAPSA28 disease activity states was high: 0.92 (95% CI 0.92 to 0.92). Standardised response means for DAPSA/DAPSA28 were -0.96/-0.92 for visits after biological DMARD-initiation. Baseline DAPSA/DAPSA28 had high correlation with 28-joint disease activity score with CRP (r=0.87/r=0.93), simplified disease activity index (r=0.92/r=0.99), p<0.001. Bland-Altman plot showed better agreement between DAPSA/DAPSA28 for low than high disease activity. DAPSA/DAPSA28 were similarly correlated to Health Assessment Questionnaire; r=0.60/0.62, p<0.001. DAPSA/DAPSA28 discriminated patients reporting their symptom state as acceptable versus not acceptable equally well: mean (SD) 9.1 (8.7)/8.4 (8.0) and 24.2 (14.9)/22.5 (13.8), respectively.
Our study suggests that data sets with only 28-joint counts available can be used to calculate DAPSA28, especially in patients with low disease activity. DAPSA28 showed good criterion, correlational and construct validity and sensitivity to change. Still, our results support that 66/68 joint count should be performed and the original DAPSA should be preferred in PsA.
使用 28 个而不是 66 个肿胀/68 个触痛关节计数（SJC/TJC）来测试改良的银屑病关节炎疾病活动指数（DAPSA）的心理测量性能。
我们纳入了来自丹麦国家质量登记处 DANBIO 的银屑病关节炎（PsA）患者，分为检查队列（n=3157 例患者，23987 次就诊）和验证队列（n=3154 例患者，24160 次就诊）。我们定义 DAPSA28 =（28TJC×转换系数）+（28SJC×转换系数）+患者整体（0-10VAS）+疼痛（0-10VAS）+C 反应蛋白（CRP）（mg/dL）。在检查队列中使用广义估计方程确定转换系数，并在验证队列中评估。
我们估计 DAPSA28 =（28TJC×1.6）+（28SJC×1.6）+患者整体（0-10VAS）+疼痛（0-10VAS）+CRP（mg/dL）。DAPSA/DAPSA28 具有相似的鉴别能力，表现为标准化均差（DAPSA，0.90；DAPSA28，0.93），可区分高疾病活动度和低疾病活动度的患者。DAPSA/DAPSA28 疾病活动状态的二次加权kappa 值较高：0.92（95%CI 0.92 至 0.92）。DAPSA/DAPSA28 的标准化反应均值在生物 DMARD 起始后的就诊中分别为-0.96/-0.92。基线 DAPSA/DAPSA28 与 28 关节疾病活动评分与 CRP（r=0.87/r=0.93）、简化疾病活动指数（r=0.92/r=0.99）具有高度相关性，p<0.001。Bland-Altman 图显示，DAPSA/DAPSA28 在低疾病活动度下的一致性优于高疾病活动度。DAPSA/DAPSA28 与健康评估问卷同样相关：r=0.60/0.62，p<0.001。DAPSA/DAPSA28 同样可以很好地区分报告症状状态为可接受和不可接受的患者：平均（SD）分别为 9.1（8.7）/8.4（8.0）和 24.2（14.9）/22.5（13.8）。
本研究表明，只有 28 个关节计数的数据集可用于计算 DAPSA28，尤其是在疾病活动度较低的患者中。DAPSA28 显示出良好的标准、相关性和结构有效性以及对变化的敏感性。尽管如此，我们的结果仍支持应进行 66/68 个关节计数，并在 PsA 中首选原始 DAPSA。
