A psychometric validation of two brief measures to assess palliative need in patients severely affected by multiple sclerosis.

Abstract

Most patient-reported outcome measurement tools in multiple sclerosis (MS) are geared toward less severely affected patients. Palliative care outcome measures have not been validated in patients with MS. To assess the psychometric properties of the Core-Palliative Care Outcome Scale (Core-POS) and POS-MS-Symptoms (POS-MS-S) in patients severely affected by MS. Secondary analyses were conducted on data from a Phase II trial of palliative care in MS. Patients completed assessments using the following five scales: Core-POS, POS-MS-S, the Multiple Sclerosis Impact Scale, the United Kingdom Neurological Disability Scale, and the Expanded Disability Status Scale. Data quality, scaling assumptions, acceptability, internal consistency, and construct validity of the Core-POS and POS-MS-S were determined using standard psychometric methods. The 46 participants had a mean ±SD age of 52.8 ±10.6 years. The mean Expanded Disability Status Scale score was 7.9 ± 1.2. Missing data were low (0 and 0.2% for the Core-POS and POS-MS-S, respectively), and floor and ceiling effects were absent. Internal consistency was good (Cronbach's alpha for the Core-POS and POS-MS-S were 0.72 [95% CI 0.56-0.84] and 0.81 [95% CI 0.72-0.89], respectively). Construct validity was consistent with a priori hypotheses 17 of 20 times. Psychometric analyses confirm that the Core-POS and POS-MS-S are acceptable, reliable, and valid in patients severely affected by MS.