Development and evaluation of an Asthma-Specific Quality of Life (A-QOL) questionnaire.
BACKGROUND
Few health-related quality of life (HRQOL) studies of asthma patients have been conducted in Korea, mainly due to the lack of a psychometrically validated asthma-specific instrument.


OBJECTIVE
The aims of the present study were to develop and evaluate an instrument for assessing HRQOL in Korean asthma patients (asthma-specific quality of life, [A-QOL]).


METHODS
Items were generated using in-depth interviews and a review of the literature and were subsequently reviewed by a panel of experts. Content-validated items were evaluated psychometrically with the aid of 422 asthma patients who were recruited from university hospitals in South Korea. The participants were asked to complete a preliminary A-QOL questionnaire (comprising the content-validated items), the Asthma Control Test, the Center for Epidemiologic Studies-Depression Survey (CES-D), and the Short Form-36 Health Survey. The Global Initiative for Asthma Guideline classification was also used to classify the severity of asthma. The psychometric properties of the data were analyzed.


RESULTS
Thirty-six preliminary items were generated, from which factor analysis extracted a six-factor solution. Six of the items were not loaded significantly on any of the factors, such that they were not heterogeneous items. Multi-trait scaling analysis supported item convergence and discriminant validity. The A-QOL was associated significantly with the CES-D. Patients with controlled asthma had higher A-QOL scores than those whose asthma was not controlled. The quality of life measured by the A-QOL was more sensitive than that measured by the generic Short Form-36 Health Survey. The values of Cronbach's alpha for the subscales of the A-QOL were all greater than 0.70. The responsiveness of all subscales, excluding the "environmental distress" subscale, was established.


CONCLUSIONS
The A-QOL is an easily applied tool that exhibits good psychometric properties for asthma patients. The A-QOL questionnaire is valid for and can be used reliably in both practice and clinical trials.
Lee
Eun-Hyun
EH
Graduate School of Public Health, Ajou University, Suwon, Republic of Korea. ehlee@ajou.ac.kr
Kim
Sang-Ha
SH
Choi
Jeong-Hee
JH
Jee
Young-Koo
YK
Nahm
Dong-Ho
DH
Park
Hae-Sim
HS
D000293:Adolescent; D000328:Adult; D000368:Aged; D001249:Asthma / Q000175:diagnosis / Q000523:psychology* / Q000628:therapy; D032882:Comprehension; D003627:Data Interpretation, Statistical; D003863:Depression / Q000175:diagnosis / Q000523:psychology; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D007723:Korea; D008297:Male; D008875:Middle Aged; D011594:Psychometrics; D011788:Quality of Life; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires