Patient-reported outcome measures for symptom perception during an exacerbation in cystic fibrosis

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, that were developed for CF patients, and had been employed at least once during pulmonary exacerbations. The PROMS included were critiqued for relevance and psychometrics, according to the criteria of the FDA guideline and the COSMIN checklist.
Results: Five PROMS were identified, all measuring symptom perception. Two were developed to assess symptom severity during pulmonary exacerbations: the CF Respiratory Symptom Diary (CFRSD) and the Symptom Scoring System. Of the other three, which also included symptom scores of two quality of life (QoL) measures, one assessed symptom severity exclusively, and two measured symptom severity in addition to other dimensions (such as symptom distress).
All five instruments measured respiratory symptoms. Other relevant symptoms, such as energy and emotions, were covered by four instruments; pain and gastrointestinal symptoms by two. All instruments demonstrated good internal consistency and sensitivity to change over a period up to four weeks. The symptom scores of the two QoL measures with longer recall periods are not suitable for measuring assessed changes in a period of less than two weeks. Criterion validity for gastrointestinal sub-scores has not been established. Other than for the Symptom Score System, discriminant validity was established in all of the instruments reviewed.
Conclusions: Of the current PROMS used during CF pulmonary exacerbations, only two have been developed for this purpose and only one – the CFRSD – fulfilled all FDA guideline criteria. To date, there is no instrument that assesses exacerbation-specific symptom distress.