Hand osteoarthritis (OA) has a wide spectrum of clinical presentations and physical function is one of the core domains where patients suffer. The Functional Index for Hand Osteoarthritis (FIHOA) is a leading assessment tool for hand OA-related functional impairment. Our objective was to make a Japanese version of FIHOA (J-FIHOA) and validate it among Japanese hand OA patients. Forward and backward translation processes were completed to create a culturally adapted J-FIHOA. A prospective, observational multicenter study was undertaken for the validation process. Seventeen collaborating hospitals recruited Japanese hand OA patients who met the American College of Rheumatology criteria. A medical record review and responses to the following patient-rated questionnaires were collected: J-FIHOA, Hand20, Health Assessment Questionnaire (HAQ), numerical rating scale for pain (NRS pain) and Short Form 36 Health Survey (SF-36). We explored the structure of J-FIHOA using factor analysis. Cronbach’s alpha coefficients and item-total correlations were calculated. Correlations between J-FIHOA and other questionnaires were evaluated for construct validity. Participants in clinically stable conditions repeated J-FIHOA at a one- to two-week interval to assess test-retest reliability. To evaluate responsiveness, symptomatic patients who started new pharmacological treatments had a 1-month follow-up visit and completed the questionnaires twice. Effect size (ES) and standardized response mean (SRM) were calculated with pre- and post-treatment data sets. We assessed responsiveness, comparing ES and SRM of J-FIHOA with other questionnaires (construct approach). A total of 210 patients participated. J-FIHOA had unidimensional structure. Cronbach’s alphas (0.914 among females and 0.929 among males) and item-total correlations (range, 0.508 to 0.881) revealed high internal consistency. Hand20, which measures upper extremity disability, was strongly correlated with J-FIHOA (r = 0.82) while the mental and role-social components of SF-36 showed no correlations (r = − 0.24 and − 0.26, respectively). Intraclass correlation coefficient for test-retest reliability was 0.83 and satisfactory. J-FIHOA showed the highest ES and SRM (− 0.68 and − 0.62, respectively) among all questionnaires, except for NRS pain. Our results showed J-FIHOA had good measurement properties to assess physical function in Japanese hand OA patients both for ambulatory follow-up in clinical practice, and clinical research and therapeutic trials.

中文翻译：

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跨文化翻译，改编和验证日语版手部骨关节炎（J-FIHOA）功能指数。

手部骨关节炎（OA）具有广泛的临床表现，而身体功能是患者所遭受的核心领域之一。手骨关节炎功能指数（FIHOA）是与手OA相关的功能障碍的领先评估工具。我们的目标是制作日文版FIHOA（J-FIHOA），并在日本手部OA患者中进行验证。完成了向前和向后的翻译过程，以创建具有文化适应性的J-FIHOA。为验证过程进行了前瞻性，观察性的多中心研究。十七家合作医院招募了符合美国风湿病学会标准的日本手工OA患者。收集了病历回顾和对以下患者评分问卷的答复：J-FIHOA，Hand20，健康评估问卷（HAQ），疼痛数字评级量表（NRS疼痛）和36简表健康调查（SF-36）。我们使用因子分析探索了J-FIHOA的结构。计算了克朗巴赫（Cronbach）的alpha系数和项目总体相关性。对J-FIHOA与其他问卷之间的相关性进行了结构效度评估。临床稳定条件下的参与者以一到两周的间隔重复J-FIHOA，以评估重测信度。为了评估反应性，开始使用新药治疗的有症状患者进行了1个月的随访，并完成了两次问卷调查。使用治疗前和治疗后的数据集计算效应量（ES）和标准化反应平均值（SRM）。我们评估了反应能力，将J-FIHOA的ES和SRM与其他问卷进行了比较（构建方法）。共有210名患者参加。J-FIHOA具有一维结构。Cronbach的alpha（女性为0.914，男性为0.929）和项目之间的相关性（范围为0.508至0.881）显示出很高的内部一致性。测量上肢残疾的Hand20与J-FIHOA密切相关（r = 0.82），而SF-36的心理和角色社会成分则没有相关性（r = − 0.24和− 0.26）。类内相关系数用于重测信度为0.83，令人满意。除NRS疼痛外，在所有问卷中，J-FIHOA的ES和SRM最高（分别为− 0.68和− 0.62）。我们的结果表明，J-FIHOA具有良好的测量性能，可以评估日本手OA患者的身体功能，以进行临床实践，临床研究和治疗试验中的动态随访。