Translation and validation of the Test of Adherence to Inhalers (TAI) questionnaire among adult patients with asthma in Malaysia.

ABSTRACT

OBJECTIVE: The Test of Adherence to Inhalers (TAI) is a validated self-reported questionnaire that can reliably assess adherence to inhalers through patient self-report. However, it was not available in Bahasa Melayu (BM) language, nor has it been validated for use in the Malaysian population. The study aimed, therefore, to translate the 10-item TAI questionnaire into BM and evaluate its psychometric properties. METHODS: The translation of the English version of the valid 10-item TAI questionnaire into BM was followed by subjecting it to a series of tests establishing factorial, concurrent and known group validities. Concurrent validity was assessed through Spearman's rank correlation coefficient against pharmacy refill-based adherence scores. Known group validity was assessed by cross-tabulation against asthma symptom control and using chi-square test. The internal consistency of the test scale was determined by a test-retest method using Cronbach's alpha (α) value and intraclass correlation coefficients. RESULTS: A total of 120 adult asthma patients participated in the study. A 2-factor structure was obtained and confirmed with acceptable fit indices; CFI, NFI, IFI, TLI >0.9 and, RMSEA was 0.08. The reliability of the scale was 0.871. The test-retest reliability coefficient for the total sum score was 0.832 (p < 0.01), which indicated good reliability. The 10-item TAI-BM established concurrent and known group validities. The sensitivity and specificity of the tool were >85%. CONCLUSIONS: The scale successfully translated into BM and validated. The 10-item TAI-BM appears fit for use in testing inhaler adherence of Malaysian patients with asthma.