RESUMO
Regular physical activity (PA) and limited sedentary time (SED) are highly recommended in international guidelines for patients after a myocardial infarction (MI). Data on PA and SED are often self-reported in clinical practice and, hence, reliable and valid questionnaires are crucial. This study aimed to assess the test-retest reliability, criterion validity and agreement of two PA and one SED questionnaire commonly used in clinical practice, developed by the Swedish National Board of Health and Welfare (BHW) and the Swedish national quality register SWEDEHEART. Data from 57 patients (mean age 66 ± 9.2 years, 42 males) was included in this multi-centre study. The patients answered three questionnaires on PA and SED at seven-day intervals and wore an accelerometer for seven days. Test-retest reliability, criterion validity and agreement were assessed using Spearman's rho and linearly weighted kappa. Test-retest reliability was moderate for three of the six-sub questions (k = 0.43-0.54) within the PA questionnaires. For criterion validity, the correlation was fair within three of the six sub-questions (r = 0.41-0.50) within the PA questionnaires. The SED questionnaire had low agreement (k = 0.12) and criterion validity (r = 0.30). The studied questionnaires for PA could be used in clinical practice as a screening tool and/or to evaluate the level of PA in patients with an MI. Future research is recommended to develop and/or evaluate SED questionnaires in patients with an MI.