Psychometric validation of a patient-reported single-item assessment of ‘Good Day Bad Day’ in a neurogenic orthostatic hypotension population treated with droxidopa

Abstract

Background Symptoms of neurogenic orthostatic hypotension (nOH), including lightheadedness/dizziness, presyncope, syncope, and falls, can lead to impaired functional ability and reduced quality of life. Because the severity and frequency of nOH symptoms fluctuate, it may be difficult for patients to accurately quantify the effect of symptoms on their daily lives using available outcome measures. A new single-item instrument, the ‘Good Day Bad Day,’ was developed, and its psychometric validity was assessed in patients with nOH. Methods Data from a 6-month, prospective, observational cohort study of patients with nOH who were newly initiating droxidopa treatment were used. Patients were asked to quantify the number of good and bad days in the previous 7 days and responded to other validated patient-reported outcomes instruments. The concurrent and discriminant validities and the stability of the Good Day Bad Day instrument were assessed. Results A total of 153 patients were included in the analysis (mean [SD] age, 62.3 [17] years). Change in the number of good days moderately correlated with improvements in other patient-reported outcomes (rho value range, −0.38 to −0.61). When data were examined categorically (low vs high symptom severity), the mean number of good days was higher in subgroups representing low symptom severity across measures at 1, 3, and 6 months (all P ≤ 0.01). Conclusions The Good Day Bad Day instrument provided good discrimination at baseline and over time and may aid in assessment of the effects of nOH symptoms on patients.