Development and Initial Validation of Quality-of-Life Questionnaires for Intermittent Exotropia Ophthalmology 2010;117:163–168 Pf. 임혜빈 / R2 정병주
Introduction Evaluation of severity of intermittent exotropia 사시각, 조절 능력, 입체시 => 검사의 변동성이 큼!! Health-related quality of life (HRQOL) Helpful in determining Indications for intervention 개발 검증, 타당성 확인
Patients and Methods Development & Initial validation Children with IXT, with one of their parents Divergence excess or basic-type IXT No amblyopia No neurodevelopmental delay No coexisting ocular pathologic features
Patients and Methods Phase 1 : Development Development of Final Intermittent Exotropia Questionnaires Child (35 items) Proxy (35 items) Parent (46 items) 27 children with IXT (age range, 2–17 years; median age, 5 years) 2 (7%) of 27 : previous surgery & recurrent IXT. Median angle of : 20 pd (range, 10–30 pd) 4 (15%) children : refractive correction. 52 %: female, and 93% : white 15 (56%) : 5 to 17 years (6 of 15 : 5 to 7 years of age and 9 of 15 : 8 to 17 years of age) completed the child questionnaires Proxy questionnaires : parents of the 5- to 17-year-old children 13 (87%) of 15 : the mother completed the proxy questionnaire. Parent questionnaires : completed by all 27 parents Proxy - 대리인
Patients and Methods Phase 1 : Development For 5- to 7-year-olds Simple language and a 3-point Likert-type scale Not at all, sometimes, a lot, and “I don’t know.” For 8- to 17-year-olds A 5-point Likert-type scale Never, almost never, sometimes, often, almost always, and “I don’t know.” For proxy and parent Likert type scale : likert 척도 : 응답자들에게 서술형으로 작성된 각 질문 항목에 대한 동의 또는 반대의 정도를 표시하도록 하는방법
Patients and Methods Phase 1 : Development Analysis of Child ,Proxy & Parent Questionnaires. Exclusion criteria (1) 20% 이상에서 부적절한 문항이라고 판단한 문항 (2) 80% 이상에서 “not at all” 이라고 답한 문항 (3) 단어나 질문의 의미가 불분명한 문항 (4) Intervention 후에는 적용하기 애매한 문항 Standard item reduction methodology Item-total correlation rank plot using Cronbach’s a Inflection point to determine the threshold for retaining items Factor analysis & loading threshold (0.7) 신뢰성 지수(Cronbach's α) - 동일한 개념을 측정하기 위해 여러개의 항목을 이용하는 경우, 신뢰도를 저해하는 항목을 찾아내어 측정도구에서 제외시킴으로써 측정도구의 신뢰도를 높이기 위한 방법. 즉, 내적일관도(internal consistency reliability)를 측정하는 방법 ☞ Cronbach's α 평가 - "초기연구단계에서 α가 0.5∼0.6수준이면 비교적 양호하고, 0.7이상이면 대체로 채택가능 (acceptable)하다 - "신뢰계수 α의 가장 큰 문제점은 아직까지 모든 연구자가 수용할만한 신뢰계수의 기준에 대해 정확한 값이 없다는 점이다. 그러나 일반적으로 사회과학에서는 α = 0.70을 기준으로 한다“. 요 인 분 석 (Factor Analysis) - 분석상의 편의를 위해 변수(요인)축소 목적 측정의 타당성을 저해하는 변수들을 추출하는데 이용 상호관련성있는 변수들끼리 유형별로 분류 요인 수 결정 방법 : 고유치(Eigen value) : 각각의 요인으로 설명할 수 있는 변수들의 분산의 총합으로 각 요인별로 모든 변수의 요인부하량을 제곱하여 더한 값. 즉, 각 요인이 얼마나 많은 설명력을 갖고 있는지를 나타냄 Scree test : Eigen값으로 chart를 그린후, Eigen값이 줄어드는 정도가 미미해지는 곳 선택
Patients and Methods Phase 2 : Initial validation Initial Validation of Final Intermittent Exotropia Questionnaires 5-to 7-year-olds Not at all 100 Sometimes 50 A lot 0 8- to 17-year-olds, Proxy and parent Never 100 Almost never 75 Often 25 Almost always 0 From 100 (best HRQOL) to 0 (worst HRQOL) : median score 측정
Patients and Methods Phase 2 : Initial validation Patients: Intermittent Exotropia Group (33 children) All 33 children completed the 12-item final child questionnaire 31 of 33 parents completed the 12-item proxy questionnaire (2 overlooked) All 33 parents completed the 17-item parent questionnaire Patients: Control Group (49 children) All 49 children completed the 12-item child final questionnaire. All 49 parents completed the 12-item proxy questionnaire and 17-item parent questionnaire
Results Development of Final Child and Proxy Intermittent Exotropia Questionnaires 35 original items 13 items : removed by predefined exclusion criteria Item-total versus correlation rank plot Inflection point for the child (ages 5 to 17 years) and proxy Child questionnaires(16 items), proxy questionnaires(20 items) 12 common items No Difference Inflection point
Results
Results Development of Final Parent Intermittent Exotropia Questionnaire 46 original items 4 items : removed by predefined exclusion criteria Factor analysis : 3 strong factors Loading thresholds were reviewed and 0.70 was applied Total items : 17 (1) Psychosocial effects (7 items) (2) Function (8 items) (3) Surgery (2 items)
Results
Results Initial Validation of Final Intermittent Exotropia Questionnaires Median child IXTQ scores 85 (quartiles, 73–92; range, 54–100) versus 92 (quartiles, 79–96; range, 50–100; P 0.04) Does it bother you that you have to shut one eye when it is sunny? (P 0.007) Median proxy IXTQ scores 83 (quartiles, 75–94; range, 54–100) versus 98 (quartiles, 92–100; range, 65–100; P 0.0001) It bothers my child because he/she has to shut one eye when it is sunny(P 0.0001) Median parent IXTQ scores 68 (quartiles, 56–79; range, 24–100) versus 93 (quartiles, 87–99; range, 49–100; P 0.0001) Psychosocial subscale 79 (quartiles, 57–89) versus 100 (quartiles, 93–100;P0.0001) Function subscale 66 (quartiles, 50–78; range, 34–100) versus 88 (quartiles, 78–97; range, 41–100; P0.0001) Surgery subscale 50 (quartiles, 50–75; range, 25–100) versus 100 (quartiles, 100–100; range, 38–100; P0.0001)
Results Initial Validation of Final Intermittent Exotropia Questionnaires 98 92 93 85 83 68 P<0.0001 P=0.04 P<0.00001
Discussion Limitations Study sample : racially homogeneous Influenced the selection of final questionnaire items Alternative item-reduction methods : different final questionnaires Sufficient numbers were not available to analyze data
Discussion Children with IXT : worse HRQOL (lower scores) Bothered by having to close 1 eye in sunlight Unclear whether should be considered a criterion for intervention Parents of children with IXT : worse HRQOL (lower scores) Parental education: reduce parental worry The parent IXTQ : a useful tool for measuring the effectiveness Useful in the clinical assessment of IXT and for clinical trials.