Development of Rasch-based short screenings for the assessment of treatment motivation in patients with cardiovascular diseases

Abstract

Purpose: The aim of the study was to develop unidimensional test-fair and economic short screenings to assess treatment motivation in patients with cardiovascular diseases using the Rasch analysis.

Materials and methods: After pretesting for relevance and comprehension, a pool of 132 items on treatment motivation was completed by a sample consisting of 1168 patients with cardiovascular diseases recruited in two German cardiological rehabilitation centers. Confirmatory factor analyses and the Rasch analyses were conducted.

Results: The confirmatory factor analyses confirmed a three-factor structure of the treatment motivation construct with task self-efficacy, outcome expectancies and intention as factors. Using the Rasch analysis for each of the three factors and removing items with misfit, differential item functioning and local response dependency reduced the initial item pool to the three short screenings. The short screenings fit to the Rasch model with a root mean square error of approximation (RMSEA = 0.021 (task self-efficacy; seven items); RMSEA = 0.024 (outcome expectancies; 12 items), RMSEA = 0.027 (intention; nine items). Person-separation reliability was 0.81, 0.82, and 0.73. Unidimensionality could be verified.

Conclusions: The calibrated, unidimensional short screenings provide a psychometrically sound option for an initial- and follow-up assessment of treatment motivation in rehabilitation patients with cardiovascular diseases. Further testing in other cardiovascular diseases populations is needed to increase generalizability.

Implications for rehabilitation

• New short screenings for the assessment of treatment motivation: task self-efficacy, outcome expectancies, intention in rehabilitation patients with cardiovascular diseases are available.

• Treatment motivation short screenings_{self-efficacy/outcome expectancies/intention} consist of seven items (treatment motivation short screening_{self-efficacy}), 12 items (treatment motivation short screening_{outcome expectancies}), nine items (treatment motivation short screening_intention) and are therefore especially timesaving.

• The short screenings demonstrate good psychometric properties, cover a wide spectrum of task self-efficacy, outcome expectancies and intention, and are free of local dependencies and of differential item functioning regarding to gender, age and cardiovascular diagnoses.

• Using a Rasch based unidimensional short screening is a test-fair and economic method to assess patients’ treatment motivation, which might help to improve rehabilitation health care tailored to patients’ needs.

Keywords:

• Treatment motivation
• cardiological disease
• short screening
• item response theory
• Rasch model
• rehabilitation

Acknowledgements

We are grateful to all patients who participated in this study. We would like to specifically thank for support of data collection: Reha-Zentrum Bad Driburg (Klinik Berlin) and Reha-Zentrum Bad Pyrmont (Klinik Weser).

Disclosure statement

The authors report no conflicts of interest.

Data availability

The data that support the findings of this study are available from the corresponding author, [HS], upon reasonable request.

Additional information

Funding

This study was funded by the Deutsche Rentenversicherung Bund (grant number: 8011-106-31/31.117).

This study was funded by the Deutsche Rentenversicherung Bund (grant number: 8011-106-31/31.117).