Psychometric Properties and Clinical Utility of the Distress Thermometer in Caregivers of Persons With Multiple Sclerosis.

Background: Caregivers of persons with multiple sclerosis (MS) report high levels of distress. The National Comprehensive Cancer Network Distress Thermometer (DT) is used extensively with patients with cancer and their caregivers but has not been tested in nononcology caregivers. The purpose of this study was to examine the psychometric properties and clinical utility of the barometer portion of the DT in caregivers of persons with MS.

Methods: A secondary analysis was performed of data from a randomized trial comparing the effectiveness of 2 interventions aimed at reducing psychological outcomes associated with caregiving. The DT and the 4-item Patient-Reported Outcomes Measurement Information System Anxiety and Depression scales, which were administered at baseline, were used for all analyses. Construct validity (known groups) and convergent validity (interscale correlations) were evaluated. Receiver operating characteristic curve analysis was used to evaluate clinical diagnostic test evaluation.

Results: The DT had good construct validity supported by strong correlations for known-groups analyses and good convergent validity (r = 0.70-0.72). The DT also demonstrated good discrimination for anxiety (area under the curve [AUC] = 0.83) and depression (AUC = 0.80). The optimal screening cut point on the DT was 4 for anxiety and 5 for depression.

Conclusions: The barometer portion of the DT demonstrates good psychometric properties and clinical utility in caregivers of persons with MS. This is the first examination of the DT in MS care partners.