Quantification of dyspnea using descriptors: Development and initial testing of the Dyspnea-12 J Yorke, S H Moosavi, C Shuldham, P W Jones (Thorax ; 65 : ) R2 Jang Na-eun Journal conference

Dyspnea, like pain perception, consists of “sensory quality” and “affective components” - Dyspnea is a debilitating and distressing symptom that is reflected in different verbal descriptors - It is a common and distressing symptom in cardio-respiratory disease BACKGROUND BACKGROUND

Dyspnea has been measured in two ways (1) Directly, using modified Borg or visual analogue scales, in persons experiencing dyspnea at rest or in response to various stimuli (2) Indirectly, by asking the respondent to report the level of physical activity they are not able to accomplish because of dyspnea - while indirect methods provide useful information, they do not quantify dyspnea; they measure its effects on activity BACKGROUND BACKGROUND

OBJECTIVES OBJECTIVES To develop an instrument that measures overall dyspnea severity using descriptors that reflect its different aspects

METHODS METHODS Research design Development of the initial item pool Study 1 Item reduction and preliminary testing Study 2 Dyspnea-12 validation Phase 1 Item reduction Phase 2 Item reduction Phase 3 Exploratory principal component analysis Phase 4 Validity testing of the final 12-item set

METHODS METHODS A pool of 81 items was generated from published literature reporting the language to describe breathlessness - using the terms : dyspnea/breathless/language/descriptor/questionaire/qualitative The 81 items, each with response options are none, mild, moderate or severe -> Patients select response of each item that ‘best matched’ their current experience of being breathless Two studies were performed Development of the initial item pool

METHODS METHODS Participants - Breathless patients (n=358) with a primary diagnosis of COPD, ILD or chronic heart failure (CHF) - Each participant completed one of three randomly 1) allocated 81-item descriptor lists 2) the Medical Research Council(MRC) dyspnea scale 3) two modifiied Borg scales ( Borg-intensity and Borg-distress scales) - assessed ‘current level of breathlessness’ and ‘current level of distress caused by breathlessness’ Study 1 Item reduction and preliminary testing

METHODS METHODS Phase 1 Item reduction Phase 2 Item reduction using hierarchical methods Items were excluded if ≥50% of patients gave a response of ‘none’ Items influenced by age at p<0.05 were removed Survived items were analysed with Rasch Testing how well each item contributes to the concept being measured (breathlessness severity) -> the poorest item is removed and the remaining item is then retested -> this process is continued until each item has a good fit to the model and the stability of the overall item set

METHODS METHODS Phase 3 Exploratory principal component analysis (PCA) Phase 4 Validity testing of the final 12-item set PCA was used to assess the underlying structure of the final item set The final item set consists of 12 items The score is calculated using simple addition of the responses for item - ranges from 0 to 36 -> 0 represents no breathlessness -> 36 represents maximal severity Examined relationships between the 12-item set total score, MRC, dyspnea grade, Borg-intensity and Borg-distress scales

METHODS METHODS We tested Dyspnea-12 reliability and validity - The Dyspnea-12 asks patients to respond in relation to their breathlessness ‘ these days’ and is designed to capture the patient’s general perception about their current state rather than a record specific to the day of testing Participants - with a further group of 53 patients with COPD - participants completed the Dyspnea-12, MRC dyspnea scale, Hospital Anxiety and depression scale (HADS), lung function tests and 6-minute walk distance (6MWD) Study 2 Dyspnea-12 validation

RESULTS RESULTS Study 1 Item reduction and preliminary testing Phase 1 Item reduction Phase 2 Item reduction Phase 3 Exploratory principal component analysis Phase 4 Validity testing of the final 12-item set A total of 358 patients completed 47 items were initially removed 22 items were removed 12 items survived the item reduction process, and make up the final item set

RESULTS RESULTS Phase 3 Exploratory principal component analysis 5 명의 소비자에 의한 fast-food 점의 평가 소비자대기시간청결종업원음식 맛음식온도음식신선도 A B C D E 서비스품질 음식품질 “ 그 fast-food 점은 음식의 질은 높으나 서비스는 나쁘다 ” 라고 해석할 수 있다. 다수 변수들을 소수의 요인으로 축약하여 원자료의 특성을 해석 가능한 통계 기법 요인분석결과를 해석할 때 일반적 상관관계계수의 통계적 유의성 대신 실제 적 유의성 (practical significance) 에 관심을 가지는데, 흔히 요인적재값이 ±.50 이상일 때 실제적 유의성을 갖는 것으로 받아들임 주성분 분석

RESULTS RESULTS Phase 3 Exploratory principal component analysis The first component called ‘physical’ contained seven items and the second, called ‘affect’, contained five items One item ‘irritating loaded >0.5 on both components

RESULTS RESULTS Phase 3 Exploratory principal component analysis Explain the severity associated with the groups of items The ‘physical’ items were associated with a lower overall level of dyspnea severity whereas the ‘affective’ items were associated with more severe breathlessness

RESULTS RESULTS Phase 4 Validity testing of the final 12-item set

RESULTS RESULTS Dyspnea-12 demonstrated good internal reliability and good test-retest reliability - Mean Dyspnea-12 score was strongly associated with HADS scores - Dyspnea-12 correlated significantly with FEV1 (p=0.03), 6MWD (p<0.01) and MRC grade (p<0.001) - Interview participants rated the Dyspnea-12 as easy to complete, easy to understand and helpful Study 2 Dyspnea-12 validation

DISCUSSION DISCUSSION This is a unique instrument since it quantifies breathlessness using descriptions by patients of its qualities and affective - We have developed and conducted initial validity testing of the Dyspnea-12 with other relevant measures - This instrument was developed in three disease populations We used advanced methodology to ensure reliable measurement properties (the first application of Rasch methodology) - The minimum level of items required to represent the breathlessness severity - We found that 12 items provided the best compromise

DISCUSSION DISCUSSION We are confident that the Dyspnea-12 items are relevant, appropriate and truly capture patient’s perceptions - Developed our initial 81 item pool after a systematic review of existing literature - Patient-reported outcomes : derived from the words used by patients to describe disease effects and their clinical state Difference in breathlessness severity associated with physical and affective items - ‘Physical’ items tended to be associated with milder severity, whereas the ‘affective’ items were associated with more severe breathlessness

DISCUSSION DISCUSSION Limitations - Dyspnea-12 is currently validated for the English-speaking poppulation : translations into other languages will require careful translations into other languages will require careful translation

CONCLUSIONS CONCLUSIONS The Dyspnea-12 forms a unidimensional measure that reflects both the physical and affective aspects of dyspnea It provides a global score of breathlessness severity and can measure dyspnea in a variety of disease Patients found the Dyspnea-12 was easy to complete and understand, and helpful in expressing their experience of being breathless