Thai version of the Minnesota Living with Heart Failure Questionnaire: psychometric testing using a longitudinal design

Background: The Minnesota Living with Heart Failure Questionnaire (MLHFQ) is the most widely used diseasespecific instrument for heart failure (HF). However, a Thai version of the MLHFQ has not been available yet. Objective: Test the psychometric properties of the Thai version of the MLHFQ in terms of practicality, reliability, validity, and responsiveness, using a longitudinal design. Methods: One hundred eighty HF outpatients (mean age: 65±12 years; 58% male) were interviewed at Phramongkutklao Hospital, Bangkok between December 2008 and August 2009. Practicality was assessed with interview-times. Reliability was evaluated using Cronbach’s α and intraclass correlation coefficients (ICCs). Validity was tested with correlations between the MLHFQ scores and the SF-36 scores, confirmatory factor analysis, and known-groups validity. Responsiveness was observed with effect sizes (ES) and minimal clinically important differences (MCID). Results: The averaged interview-time was approximately five minutes. The Cronbach’s α and ICCs of the MLHFQ were 0.86-0.93 and 0.84-0.88, respectively. The MLHFQ scores were moderately correlated with the Short Form-36 Health Survey (SF-36) scores, and discriminated the patients with different classes by New York Heart Association. The average ES were medium, ranging from 0.2 to 0.5. The MCID ranged from 1.4 to 14.5 for improved patients and from -1.4 to -12.7 for worsened patients. Conclusion: The Thai version of the MLHFQ showed acceptable psychometric properties. It can be used as a disease-specific instrument to measure health-related quality of life of Thai patients with HF.