OBJECTIVES: The symptom severity scale of the Uterine Fibroid Symptom and Quality of Life (UFS-QOL) instrument contains 8 items and is multi-factorial. The objectives were to determine the subscale (factor) consisting of items relevant to most women with heavy menstrual bleeding (HMB) associated with uterine fibroids (UF), assess its psychometric properties, and determine its responder threshold.

METHODS: Analyses were based on pooled, blinded data from the first one third of patients with HMB enrolled in two Phase 3 studies of relugolix in uterine fibroids (N=254). Factor analyses were done on the UFS-QOL symptom severity scale. The subscale consisting of symptoms experienced by most patients was chosen for further analysis and its psychometric properties were evaluated. The meaningful change threshold was derived by anchor‑based methods with change in PGA of symptom severity as an anchor. Within and between anchor group changes in the subscale scores from Baseline to Week 24 were evaluated using pair t-test analysis of variance. Cumulative distribution function and probability density function curves were used as supportive information.

RESULTS: Factor analyses revealed that the UFS-QOL symptom severity scale consisted of 3 factors. Factor 1 had three items representing common symptoms of HMB in UF; this factor was named the Bleeding and Pelvic Discomfort (BPD) scale. The BPD scale had no ceiling effects; all response options were used by patients. The items of the BPD scale were found to work cohesively to inform the total score and to adequately distinguish between patients of different severities. Descriptive statistics supported the construct validity and responsiveness. A 20-point change on the BPD scale score (range from 0 - 100) is recommended as the responder threshold.

CONCLUSIONS: The BPD scale is a short patient-reported outcome measure relevant to patients with HMB due to UF that can be used to assess their symptom burden.