Psychometric Testing of the Control Attitudes Scale-Revised for Patients With a Left Ventricular Assist Device

Abstract

Background 

Perceived control, an indicator of the patient's ability to cope and thrive with a chronic illness, is a common target of nursing interventions. As of 2019, more than 25 000 patients had been implanted with a left ventricular assist device (LVAD) as a treatment of advanced heart failure. Patients with an LVAD experience significant life changes that affect anxiety, depression, health-related quality of life, and, presumably, perceived control. To adequately intervene and improve perceived control, a reliable and valid measure is needed.

Objectives 

The objectives of this analysis were to (1) assess item discrimination and anticipated range of scores of the Control Attitudes Scale-Revised (CAS-R), (2) assess the internal consistency and validity of the CAS-R, and (3) examine perceived control in a sample of patients with an LVAD.

Methods 

Two cohorts of patients with an LVAD (n = 113) were combined to evaluate the psychometric qualities of the CAS-R. Correlations among patient-reported outcomes and perceived control were used to evaluate validity. Cronbach α was used to test internal consistency. Item response theory was used to measure item discrimination and anticipated scores. Descriptive statistics describe perceived control in the sample.

Results 

Overall, the CAS-R demonstrated good internal consistency and convergent validity with other patient-reported outcomes. Using the item response theory, we saw that the CAS-R was a good predictor of lower-moderate scorers but was not good at differentiating high performers. There were several items that were poor discriminators and could be altered or discarded to create a more predictive instrument.

Conclusions 

The CAS-R is a valid and reliable instrument to measure perceived control in patients who have LVAD implants; however, more work could be done to improve item-level information.