Supplementary materials: Mapping Dermatology Life Quality Index with EQ-5D health utility index score in Chinese patients with moderate to severe psoriasis

<b>These are peer-reviewed supplementary materials for the article</b><b> </b><b>'</b><b>Mapping Dermatology Life Quality Index with EQ-5D health utility index score in Chinese patients with moderate to severe psoriasis</b><b>'</b><b> </b><b>published in the</b><b> </b><b><i>Journal of Comparative Effectiveness Research</i></b><b>.</b><b>Supplementary table 1: </b>Univariate regression analysis of patient characteristics associated with EQ-5D-5L utility index score<b>Supplementary table 2: </b>Multivariable regression analysis of patient characteristics associated with EQ-5D-5L utility index score<b>Supplementary table 3:</b> Results of the developed mapping functions from OLS model. <b>Supplementary table 4:</b> Results of the developed mapping functions from Tobit model. <b>Supplementary table 5:</b> Results of the developed mapping functions from generalized linear model. <b>Aim:</b> To establish correlation between Dermatology Life Quality Index (DLQI) and EuroQol 5-Dimension questionnaire (EQ-5D) utility score in Chinese moderate-to severe psoriasis patients and develop mapping models for health utility prediction.<b> Materials &amp; methods:</b> A total of 287 patients with moderate to severe psoriasis and at least one clinical visit with assessments for both DLQI and EQ-5D in a Chinese tertiary hospital were included. These patients were randomly split into a training set (n = 231) and a testing set (n = 56). Correlation analyses were performed to assess the relationship between DLQI (total score and item score) and EQ-5D utility index score. Twelve predictive models were developed using three statistical model approaches (ordinary least squares model, Tobit model and generalized linear model), incorporating various combinations of DLQI scores and patient characteristics (age, sex, education and comorbidities). Models were evaluated using root mean square error and mean absolute error (MAE). <b>Results:</b> A strong and significant correlation was found between DLQI total score and EQ-5D utility index score (r = -0.645, p &lt; 0.001). The best-performing model, (ordinary least squares model using DLQI total score, had the lowest root mean square error (0.122) and MAE (0.076). Validation of this model in the testing set yielded a predicted utility score with an MAE of 0.072, and an MAE-to-utility ratio of 0.084, below the validation threshold of 0.1. <b>Conclusion:</b> DLQI scores can reliably predict health utility values, offering a useful tool for clinical decision-making and health economic evaluations. The model shows strong predictive accuracy and has potential applications in the management of msPsO in China.

<b>本文为发表于<i>Journal of Comparative Effectiveness Research</i>（《比较效果研究杂志》）的论文《中国中重度银屑病患者皮肤病生活质量指数与EQ-5D健康效用指数得分的映射研究》的同行评议补充材料</b>
<b>补充表1：</b>与EQ-5D-5L效用指数得分相关的患者特征单因素回归分析
<b>补充表2：</b>与EQ-5D-5L效用指数得分相关的患者特征多因素回归分析
<b>补充表3：</b>基于普通最小二乘模型（ordinary least squares model, OLS）构建的映射函数结果
<b>补充表4：</b>基于Tobit模型构建的映射函数结果
<b>补充表5：</b>基于广义线性模型（generalized linear model, GLM）构建的映射函数结果
<b>研究目的：</b>明确中国中重度银屑病患者的皮肤病生活质量指数（Dermatology Life Quality Index, DLQI）与欧洲五维健康量表（EuroQol 5-Dimension questionnaire, EQ-5D）效用得分之间的相关性，并构建用于健康效用预测的映射模型。
<b>材料与方法：</b>本研究纳入中国某三级医院的287名中重度银屑病患者，所有受试者均完成至少一次临床就诊，并同时接受了DLQI与EQ-5D评估。将患者随机划分为训练集（n = 231）与测试集（n = 56）。通过相关性分析评估DLQI总得分及条目得分与EQ-5D效用指数得分之间的关联。采用3种统计模型方法（普通最小二乘模型、Tobit模型及广义线性模型），结合DLQI得分与患者特征（年龄、性别、受教育程度及合并症）的多种组合，构建12种预测模型。以均方根误差（root mean square error, RMSE）与平均绝对误差（mean absolute error, MAE）对模型进行评估。
<b>研究结果：</b>研究发现DLQI总得分与EQ-5D效用指数得分之间存在显著强相关性（r = -0.645, p < 0.001）。表现最优的模型为采用DLQI总得分的普通最小二乘模型，其均方根误差为0.122、平均绝对误差为0.076，均为最低。在测试集上对该模型进行验证，所得预测效用得分的平均绝对误差为0.072，效用得分比为0.084，低于0.1的验证阈值。
<b>研究结论：</b>DLQI得分可可靠预测健康效用值，可为临床决策与卫生经济学评价提供实用工具。本模型预测准确性优异，在中国中重度银屑病（msPsO）管理中具有潜在应用价值。