Translation, Cultural Adaptation, and Psychometric Properties of the Danish Version of the Anti-Clot Treatment Scale

Abstract

Background The Anti-Clot Treatment Scale (ACTS) is a 17-item, 2-factor (Burdens and Benefits), patient-reported outcome instrument to evaluate patient satisfaction with oral anticoagulant treatment. Objectives This study aimed to translate and culturally adapt the English version of the ACTS into Danish and to subsequently validate the Danish version in a population of patients treated with dabigatran etexilate for atrial fibrillation. Methods The ACTS was translated into Danish and culturally adapted. This prospective phase 4 study included 232 respondents who completed the Danish ACTS after 1 month of treatment with dabigatran etexilate for atrial fibrillation. Psychometric properties were evaluated. For test-retest reliability, the ACTS was measured twice, 2 weeks apart, in a subgroup of 50 stable patients. Results Generally, a high level of treatment satisfaction was found. Confirmatory factor analysis showed a suboptimal fit for the two-factor model of the original version. Using modification indices of confirmatory factor analysis, a four-factor model had the best fit. Cronbach's α for internal consistency was acceptable at 0.78. There was good test-retest reliability with intraclass correlation at 0.80. Smallest detectable changes (SDCs) for individual patients were 5.89 points for the total ACTS, 5.57 for the reverse Burdens, and 3.34 for Benefits scores. Group SDCs were 0.39, 0.37, and 0.22 respectively. Substantial ceiling effects limit the ability to detect improvement at the high end of the scale. Conclusion The Danish version of the ACTS has inadequate structural validity. Reliability was acceptable. Ceiling effects challenge detection of improvement of treatment satisfaction in clinical practice in this patient population.

Keywords: atrial fibrillation; cardiology; psychological distress; thrombosis.

Conflict of interest statement

Conflicts of Interest There are no conflicts of interest related directly to this manuscript.

W.J.C. has received research support from the European Society of Cardiology Working Group on Thrombosis, Boehringer Ingelheim, Siemens Healthcare, Diagnostica Stago, ANIARA, and the Health Research Fund of the Central Denmark Region; travel grants from the Danish Heart Foundation and Aarhus University; nonfinancial support from Boehringer Ingelheim, Bristol Myers-Squibb/Pfizer, and Bayer; personal and/or speaker fees from Boehringer Ingelheim, Bristol Myers-Squibb/Pfizer, Bayer, and Astra-Zeneca. She is principal investigator for clinical studies conducted by Janssens Cilag A/S, Boehringer Ingelheim, and Thrombosis Research Institute. H.H.L. has no conflicts of interest. S.D.K. has received speaker fees from Astra-Zeneca, Bayer, and Bristol-Myers Squibb/Pfizer. A-M.B.M. has received speaker fees from Bayer, Bristol-Myers Squibb/Pfizer, Boehringer Ingelheim, and Merck Sharp & Dohme Corporation (MSD).

Figures

Fig. 1

Flowchart of the study population.

Fig. 2

Distribution of the Anti-Clot Treatment Scale: total, reverse Burdens, and Benefits scores;n = 232 respondents at baseline.

Fig. 3

Optimal factor model. Factor analysis showed that a four-factor model had the best fit to the Danish version of the Anti-Clot Treatment Scale. The four domains were named Bleeding (Bl), Hassle (H), Negative affect (NA), and Benefits (Be). Standardized factor loadings are indicated for each parameter.

Fig. 4

Bland–Altman plots for two measurements in stable patients. Solid lines indicate the mean difference, while the dashed lines indicate the 95% limits of agreement.