發展青光眼患者生活功能困難度與困擾度量表題庫：前驅研究

Development of an item bank for the Glaucoma-Specific Activity Difficulty and Interference (GS-ADI) Scale: A Pilot Study

戴承芬(Cheng-Fen Tai)

指導教授 ： 蔡麗婷

國立臺灣大學/醫學院/職能治療研究所/碩士(2022年)

https://doi.org/10.6342/NTU202203143

摘要

背景與目的：青光眼 (glaucoma) 為造成全球成年人不可逆視力喪失的前三大主因之一，青光眼不僅造成不同嚴重度的視覺功能缺損，亦多方影響患者不同面向之生活功能。完整、精準、可行的生活功能評量工具，有助醫療人員快速了解患者之需求、提供符合需求且有效的治療介入之參考依據，並作為治療成效的指標。評估青光眼患者生活功能的評量工具包括：客觀臨床觀察、通用型病人報告結果評量、以及針對眼科疾病患者或青光眼患者發展的病人報告結果評量，其中以特別針對青光眼患者所發展的「病人報告結果評量 (patient-reported outcome measures, PROMs)」，最具發展價值、最能敏感偵測不同青光眼嚴重程度患者之生活功能。然而，目前這類特定青光眼疾病之病人報告結果評量，僅有半數在發展階段納入患者觀點；多數僅以古典測驗理論驗證，導致無法確保所有題目背後皆測量到單一潛在概念，患者得分並不具等距量尺特性，題目難度的估計受樣本特性影響大等限制；所有量表僅反應患者之主觀困難度，沒有評量青光眼對患者真實生活的困擾度；以及從臨床經驗，這些量表的內容沒有含括台灣特殊生活模式下，重要的視覺相關生活功能評量題目。為克服現有量表之限制，本研究目的為透過系統性文獻回顧、考量台灣文化特性和生活模式、專家審核、認知訪談及羅序分析 (Rasch analysis) 方法，發展一套適用於青光眼患者之「青光眼患者生活功能困難度與困擾度量表 [Glaucoma-Specific Activity Difficulty and Interference (GS-ADI) Scale]」題庫，並驗證其心理計量特性，包括內容效度、建構效度、差異試題功能 (differential item functioning, DIF)、羅序信度、以及題目難度與患者能力之分佈與對應 (item-person map and targeting)。
方法：本研究依據以下六個步驟發展「青光眼患者生活功能困難度與困擾度量表 (GS-ADI Scale)」題庫與驗證量表之心理計量特性：(1) 系統性文獻回顧：彙整目前特定青光眼疾病之病人報告結果評量中，所有與生活功能相關的題目。(2) 撰寫初版題庫：訂定量表題庫之架構、作答選項、計分量尺、與回憶時間範圍，並在將題目分類與篩選後，重新撰寫初版題庫之題目。另外，新增台灣生活模式下，重要的視覺相關生活功能評量題目。(3) 專家審核初版題庫：邀請臨床專家與研究學者審核步驟一及步驟二之結果，並在上述議題上達成初步的共識。(4) 認知訪談與題庫修訂：邀請青光眼患者確認初版題庫易讀性、可理解程度、題目涵蓋內容、與是否於作答過程中出現認知偏誤的情形，並根據患者回饋修改初版題庫。(5) 專家審核內容效度：邀請臨床專家與研究學者確認再版題庫各題目與青光眼及其分向度之相關性、各題目之可理解性、以及各向度之題目完整性，以此驗證題庫之內容效度。(6) 建構並驗證GS-ADI Scale：邀請青光眼患者作答GS-ADI Scale再版題庫，預計收案人數為100人，再以多向度或單向度羅序分析檢驗題庫之模型適配度，刪除不適配的題目，形成最終版GS-ADI Scale。最後，檢驗最終版GS-ADI Scale之建構效度、差異試題功能 (differential item functionaing, DIF)、羅序信度、以及題目難度與患者能力之分佈與對應 (item-person map and targeting)。
結果：於量表題庫成形階段，本研究共納入19個針對青光眼患者發展的病人報告結果評量，這些量表內容包含日常生活活動。再將此386題歸類至「視覺功能」、「行動能力」、「閱讀能力」、「（工具性）日常生活功能」、以及「社交能力」五大分向度。經題目分類與整合、訂定作答選項包括「困難度」與「困擾度」、訂定1至5分的計分量尺、以及訂定2周的回憶時間範圍後，重新撰寫題目與說明，形成初版題庫，共172題。其中，有68題 (39.5%) 由過去量表翻譯而來、45題 (26.2%) 由過去量表修改而來、59題 (34.3%) 由研究者與專家根據台灣特殊文化情境下之生活背景新增而來。接著經專家審核後，以認知訪談的方式進行量表初試，分別於第一輪與第二輪認知訪談收錄了10位及5位患有青光眼之受訪者，再將受訪者容易產生認知偏誤的題目進行修訂，結果分別於第一輪與第二輪認知訪談修訂了53.49%及4.2%的題目數量，共新增了6題，刪除「視覺功能」分向度；並重新訂定作答選項改為「使用工具或他人協助前的困難度」、「使用工具或他人協助後的困難度」、以及「重要性」，並以「使用工具或他人協助後的困難度」以及「重要性」取代初版題庫之「困難度」與「困擾度」；計分量尺改為0至4分，0分代表完全沒困難與完全不重要；回憶時間範圍改為3個月。最後再經專家審核後形成再版題庫。
接著於GS-ADI量表之選題與驗證階段，共納入了106位青光眼患者之作答反應。首先以多向度羅序模型進行分析，結果不支持量表題目為多向度之假設。因此，改將患者之作答反應以羅序整體單向度模型進行分析。結果最終版GS-ADI量表由10題與（工具性）日常生活功能相關之題目組成，其中4題具有明顯的性別差異功能，本研究以校正男女得分之方式處理。信度表現上，對整體青光眼患者來說 (N=106)，GS-ADI量表之個別信度（≧0.7的人數佔所有患者之33%）與整體平均信度 (0.49) 表現皆不佳。然對於自覺有日常生活功能困難之青光眼患者族群（生活功能困難度得分-6至4 logits的患者，N＝35），GS-ADI量表具有可接受的個別信度（≧0.7的人數佔所有患者之86.1%）與整體平均信度 (0.88)。在題目難度與患者能力之分佈與對應部分，即使是在自覺有日常生活困難的患者族群中，GS-ADI量表之題目仍有較為簡單的情形。
另外，在「重要性」之作答選項種類的可理解性上，患者對其概念的理解及作答率表現並不理想（僅57%的患者可正確理解並作答）。
結論：GS-ADI量表為一個針對青光眼患者發展，並同時考量患者從事特定日常生活活動所主觀感受之「使用工具或他人協助前後的困難度」，與該活動對患者來說之「重要性」，且經羅序模型驗證，確保量表題目背後僅測量到單一潛在概念、並具等距量尺特性之生活功能量表。每位患者僅需作答10題，臨床人員即可在自覺日常生活功能有困難之患者族群上，獲得可信的生活功能估計值。此10題亦可用於未來發展客觀臨床觀察之測驗量表，進一步比較患者主觀與客觀生活功能之異同。
然GS-ADI量表有缺乏難題、題目主要涵蓋工具性日常生活活動為主（而未包含行動、閱讀、社交等其他活動）、「重要性」之可理解性不佳的情形，這些可能影響其臨床實用性。未來，收錄更多青光眼患者（尤其是自覺生活功能有困難的患者）資料後，可再次驗證羅序信度、題目難度與患者能力之分佈與對應、再測信度、反應性等更完整之心理計量特性、並分析「重要性」資料之臨床運用價值。總結來說，GS-ADI量表未來的實用價值，可能作為低視能復健之篩檢量表，找出自覺日常生活功能有困難且認為有需要改善之患者，作為低視能復健服務之目標對象。另外，經羅序驗證之GS-ADI量表得分具等距的特性，於臨床及研究上皆可做為治療介入的成效指標。

關鍵字

青光眼 ； 生活功能 ； 病人報告結果評量 ； 認知訪談 ； 羅序模型 ； 題庫

並列摘要

Background and purpose: Glaucoma is a leading cause of irreversible blindness for people over the age of 50. Glaucoma not only impairs patients’ visual functions, but also their daily living functions. A comprehensive, reliable, and useful assessment of daily living functions is critical for health care providers to rapidly access patients’ needs and to provide effective intervention. There are several instruments of daily living functions for glaucoma patients, including objectively clinical observations, general health questionnaires, vision-specific questionnaires, and glaucoma-specific questionnaires. Among these assessments, Glaucoma-Specific Questionnaire (GSQ) plays a more important role to respond various daily performances of glaucoma patients with different levels and types of visual impairment. However, the disadvantages of the GSQs are that over half of the questionnaires did not include the patient’s perspective in the developmental phase, unable to ensure unidimensionality, and the data was not interval. In addition, all the GSQs only evaluated the difficulties, without the interference that the patients had encountered in their daily life. Further, according to the experiences of low vision rehabilitation in Taiwan, these GSQs did not include specific vision-related daily living activities which are important for the context of Taiwan. In order to overcome the limitations of the existing GSQs, this research aims to develop an item bank for “Glaucoma-Specific Activity Difficulty and Interference (GS-ADI) Scale”, and assess the scale’s psychometric properties including content validity, construct validity, Rasch reliability, Differential Item Functioning (DIF), item-person map, and targeting.
Methods: The development of an item bank for the GS-ADI Scale and psychometric property evaluation had been divided into 6 steps: (1) systematic literature review; (2) developing the original item bank, which took the context of Taiwan into consideration; (3) expert review of the original item bank; (4) cognitive interview and item bank revision; (5) assessment of the revised item bank and its content validity through expert judgment; and (6) data collection of 100 glaucoma patients using the revised version of the item bank and its psychometric validation with the Rasch analysis, including construct validity, Rasch reliability, Differential Item Functioning (DIF), item-person map, and targeting.
Results: At the first stage of item bank development, we recruited 19 glaucoma-specific patient-reported outcome measures, which contain questions for assessing daily living functions. There were 386 items in the initial item bank draft and were classified into five domains, including visual function, mobility, reading, (instrumental) activities of daily living (IADL/ADL), and social function. After the item binning and winnowing processes, the original item bank consisted of 172 items. In addition, the response options were determined to be “difficulty” and “interfering” with response levels from 1 to 5, and the recall time frame was 2 weeks. Among the original item bank, 68 (39.5%) items were translated from exiting GSQs, 45 (26.2%) items were revised from exiting GSQs, and 59 (34.3%) items were generated based on the context of Taiwan. After items had been reviewed and revised by the experts, the cognitive interview was adopted to revise or refine these items. In the first and second round of the cognitive interview, we recruited 10 and 5 interviewees and revised 53.49% and 4.2% of the total items, respectively. In addition, 6 new items were added, the visual function domain was deleted, the concept of the “difficulties” was refined to be “the difficulties before getting help from any tools or other people” or “the difficulties after getting help from any tools or other people”, and the “interfering” was replaced with the “importance”. The response level was revised from 0 to 4, and the recall time frame was changed to 3 months. The revised item bank was reviewed by the experts again to develop the final version of the item bank.
Of the 106 patients with glaucoma recruited [35 female and 71 men, mean age = 62.1 years (SD, 13.31y; range, 23–88y)], all patients completed the assessment. The results of the multidimensional Rasch analysis demonstrated that the GS-ADI Scale did not fit the assumption; therefore, a unidimensional model was adopted. Finally, there were 10 items of (instrumental) activities of daily living left, and 4 of 10 items were calibrated because of Differential Item Functioning (DIF) of sex. The reliability of the GS-ADI scale for all the patients with glaucoma (n=106) was 0.49 and 33% of patients had reliabilities of ≧0.7. These results indicated that the reliability of the GS-ADI Scale was not acceptable. However, further analysis of the data on those who perceive themselves as impaired function [GS-ADI Scale score range: -6 to 4 logit (n=35)] demonstrated that the reliabilities at group-level (0.88) and individual-level (86.1% patients had reliabilities of ≧0.7) were acceptable. As for the item-person map of the GS-ADI Scale, the result showed that the targeting of items difficulties and person abilities was poor (-2.95 logits), even for those who consider themselves functional disabled. In addition, the response option, “important”, seems difficult to understand by the patients with glaucoma, since only 57% of the patients could understand what “important” means and correctly respond to it.
Conclusion: The GS-ADI Scale may be a glaucoma-specific questionnaire, which incorporates the viewpoints of glaucoma patients regarding the “difficulty” and “importance” of performing certain daily activities. The development of the GS-ADI Scale was assessed using Rasch analysis, which could ensure the unidimensionality of the construct of the GS-ADI Scale and could provide interval data. Each patient with glaucoma only needs to answer 10 questions to get a reliable score to represent his/her daily living functions. The GS-ADI Scale was useful, especially for those who consider themselves functional disabled. In the future study, these 10 items could be used to develop a performance-based assessment and to compare the differences between the subjective and objective functions of daily living. However, GS-ADI Scale was too easy for patients with glaucoma and lacked different domains of daily living functions, such as mobility and reading. Furthermore, the underlying logic of the response option “importance”, seems difficult to understand for the patients with glaucoma. These limitations would probably interfere with the practical usage of GS-ADI Scale. Moreover, after recruiting more patients with glaucoma that considered themselves functional disabled, the Rasch reliability and item-person map could be re-assessed along with further assessing the test-retest reliability, responsiveness, and other psychometric properties. As for the clinical usage of the GS-ADI Scale, it would have the potential to be a screening test for low vision rehabilitation to help health care professionals to identify the target population and provide them with low vision rehabilitation. In addition, because the results of the GS-ADI Scale are interval data, GS-ADI Scale could be an outcome measurement for both clinical and research settings.

並列關鍵字

glaucoma ； functions of daily living ； patient-reported outcomes ； cognitive interview ； Rasch model ； item bank

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