SILPAKORN UNIVERSITY SCIENCE AND TECHNOLOGY JOURNAL, Vol 3, No 2 (2009)

Development of Smoking Cessation Health-Related Quality of Life Scale

Supakit Wongwiwatthananukit, Sanchai Wongwiwatthananukit, Rawadee Dhummauppakorn, Thitiporn Naktuan

Department of Pharmacy Practice, College of Pharmacy, University of Hawaii, Hilo, Hawaii

Department of Social Medicine, Lamphun Hospital, Lamphun

Department of Pharmacy Practice, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok

Department of Pharmacy, Phraphuthabat Hospital, Saraburi


Abstract


The purpose of this methodological research was to develop a smoking cessation health-related quality of life scale and examine the validity and reliability of this measure. The research involved 3 steps: (1) scale development, (2) expert review of the scale, and (3) testing of the scale. A total of 431 current adult smokers and ex-smokers who visited the smoking cessation clinics in hospitals/ institutes and community pharmacies participated in the study. The initial scale was developed and based on a literature review and semi-structured interviews with smokers, ex-smokers, and healthcare professionals. A five-point Likert scale was used as an item response choice. For psychometric properties, exploratory factor analysis with item analysis was used to examine the construct validity and reliability of the scale. Known group validity was used to support the evidence of construct validity. Results indicated that the scale had content validity, construct validity, and high internal consistency reliability. The scale consisted of 36 items with an overall coefficient alpha 0.93. A four-factor structure was identified and interpreted as representing four subscales: (1) general well being (18 items), (2) satisfaction (8 items), (3) craving and self-control (4 items), and (4) psychological and emotional problems (6 items). The Mann-Whitney-U test revealed ex-smokers who had quit smoking for ณ 3 months reported significantly higher quality of life scores than smokers on the four subscales (P < 0.02), demonstrating the construct validity of the scale. The findings provide preliminary evidence of scale validity and reliability.

Key Words: Health-related quality of life; Validity; Reliability; Scale; Smoking cessation; Tobacco dependence

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