Adaptation of the MacNew QLMI quality of life questionnaire after myocardial infarction to be used in the Spanish population

BACKGROUND: The advantage of specific quality of life instruments is its ability to evaluate specific issues related to the illness of interest. The aim of the present study is to developed Spanish version of the self-administered questionnaire MacNew QLMI, specific for patients after myocardial infarction (MI). MATERIAL AND METHOD: Forward and back-translation method by bilinguals was performed; once the test for feasibility and comprehension was carried out. 143 patients with a first MI completed the Spanish version of the MacNew QLMI and principal components factor analysis was performed. Reliability was assessed in 50 patients with stable MI that completed twice the questionnaire (with an interval of two weeks), measuring reproducibility and internal consistency with Student t test, intraclass correlation and Cronbach's alpha. RESULTS: Factor analysis showed a similar three dimensional structure as the original version. Intraclass correlation coeficient were 0.83, 0.87 and 0.83, and Cronbach's alpha coeficients were 0.85, 0.88 and 0.83 for the emotional, physical and social dimensions respectively. CONCLUSIONS: The Spanish version of the MacNew QLMI questionnaire has a good equivalence with the original version, a good internal consistency and a good reproducibility; it can be used in the Spanish population to study its validity.