Objectives: Sleep disturbance is a common experience in fibromyalgia (FM). The field lacks a sleep specific patient reported outcome (PRO) measure developed and validated in a FM population. The study objective is to gain an in-depth understanding of sleep in FM and to develop a PRO measure of it.
Methods: Research involved the following stages: 1) A literature review conducted to identify key concepts associated with FM patient experience of sleep and PRO measures that have been used to assess this; 2) Qualitative interviews with therapeutic area experts; 3) Focus groups with FM patients who experienced sleep disturbance; 4) Development of a conceptual framework and the Fibromyalgia Sleep Diary (FMSD); and 5) Cognitive interviews with patients to explore content validity of the FMSD.
Results: The literature review and expert interviews supported sleep disturbance being an important aspect of the FM patient experience, and underscored the need for a new FM specific sleep PRO measure. Results from the focus groups demonstrated that FM patients experience sleep disturbances that they attribute to their FM symptoms, such as pain and stiffness, confirming the importance of understanding more about sleep changes. Aspects of sleep raised by FM patients included poor sleep quality and insufficient quantity including difficulty with falling asleep, getting comfortable, and staying asleep; restlessness; light sleep; not feeling rested upon awakening; and difficulty starting the day. Cognitive interview results showed that the 8-item FMSD, developed to reflect the concepts identified above, was relevant to FM patients with content that was interpreted as intended.
Conclusions: The FMSD was developed in line with the recommendations of the FDA PRO guidance and ISPOR PRO Task Force. The qualitative evidence generated thus far strongly supports the content validity of the FMSD as a PRO measure of sleep disturbance in FM populations. Psychometric evaluation of the FMSD to demonstrate reliability, validity and sensitivity to change is recommended as a next step.