The development of the quality of life instrument in Thai patients with post myocardial infarction

Abstract

The purpose of this study was to define the meaning of Quality of Life in Thai patients with post MI., develop the Quality of Life Instrument in Thai patients with Post Myocardial Infarction (MI), test the psychometric properties of the instrument, and find the norms of QOL in Thai patients with post MI. In developing the new instrument, qualitative study was used to define the meaning and the construct of QOL by seventeen patients with post MI. An item pool was developed based on the meaning and the initial items were sixty eight. The face validity was done by thirteen experts from various disciplines. After the revision according to the comments from the experts, sixty two items were included in this instrument. Reliability tests were done by thirty participants and the result was .928. Data collection was conducted from five hundred and twenty six participants with post MI from various parts of Thailand, responding to the QOL instrument in Thai patients with post MI and other two QOL instruments: SF36 Health Survey, and MacNew Heart Disease Health Related Quality of Life Questionnaire. Data was analyzed by SPSS version 14. Construct validity of the QOL instrument in Thai patients with post MI was determined by factor analysis. Exploratory factor analysis (EFA) indicated that the instrument consisted of nine correlated factors which were analyzed from five hundred and twenty six participants. The result, the Quality of Life Instrument in Thai patients with Post MI has 9 factors, 45 items Likert's scale instrument measuring perception of quality of life in nine dimensions: 1) Symptom and Complication, 2) Psychological Comfort, 3) Family Ties 4) Adapted ADL 5) Economic Stability, 6) Spiritual Health, 7) Social Engagement, 8) Basic Physical Capacity, and 9) Feeling Empowered. The reliability of this instrument is .93 Cronbach's alpha coefficient. The criterion related validity between Thai QOL instrument and SP36 Health survey is .618 and between Thai QOL instrument and MacNew HRQOL Questionnaire is .645. Norms of QOL in Thai patients with post MI has five levels: very good, good, fair, poor, and very poor. The result indicated that the QOL instrument in Thai patients with post MI had nine dimensions which consisted of 45 items. It had the quality of the test in face validity and reliability, and had the T-score that was the norm of Thai patients with post MI. This instrument is a valuable instrument for assessing QOL in post MI patients in clinical studies or futuer studies into the measurement of QOL.