BACKGROUND: Symptom burden increases during pulmonary exacerbations of cystic fibrosis (CF), and patient-reported outcome measures (PROMs) are often used to evaluate symptoms as either primary or secondary outcomes. However, there is currently no guidance on the use of PROMs to assess symptom burden during pulmonary exacerbations.
METHODS: A systematic literature search was conducted to identify PROMs measuring symptom experience, management, or influencing factors, which were developed for CF patients and had been used at least once during pulmonary exacerbations. The PROMs included were assessed for relevance and psychometrics, according to the criteria of the United States FDA guideline and the Consensus-Based Standards for the Selection of Health Measurement Instruments (COSMIN) checklist.
RESULTS: Five PROMs were identified, all measuring symptom perception. The CF Respiratory Symptom Diary (CFRSD) and the Symptom Scoring System were developed to assess symptom severity during pulmonary exacerbations. Of the other 3, which also included symptom scores of 2 quality of life measures, one assessed symptom severity exclusively, and 2 measured symptom severity in addition to other dimensions (such as symptom distress). All 5 instruments measured respiratory symptoms. Other relevant symptoms, such as energy and emotions, were covered by 4 instruments; pain and gastrointestinal symptoms were covered by 2 measures. All of the instruments demonstrated good internal consistency and sensitivity to change over a period up to 4 weeks. The symptom scores of the 2 quality of life measures with longer recall periods are not suitable for measuring assessed changes in a period of < 2 weeks. Criterion validity for gastrointestinal subscores has not been established. Discriminant validity was established in all of the instruments reviewed except for the Symptom Score System.
CONCLUSIONS: Of the current PROMs used during CF pulmonary exacerbations, only 2 have been developed for this purpose, and only the CFRSD fulfilled all FDA guideline criteria. To date, there is no instrument that assesses exacerbation-specific symptom distress.