Raising the patient’s voice in influenza research and care: a systematic review of patient-reported outcomes

Patient-reported outcomes (PROs) enable the evaluation of patients’ perspectives in relation to their health and well-being. This paper reviews PRO instruments, regulatory guidelines, and product labels for influenza and influenza-like illness (ILI) to recommend strategies for their optimal use in clinical research. We conducted a systematic literature review of publications and electronic records reporting PROs for influenza and influenza-like illness. The systematic search identified 112 items, of which 36 were included in the final analysis (20 clinical research publications; two national guidelines; eight influenza intervention product labels; and six PRO instrument descriptions). We identified influenza-specific PRO instruments developed to assess symptom severity and impact of influenza, or the acceptability and safety of influenza interventions; several of these have been used in clinical research, enabling a better understanding of the impact of influenza and influenza interventions. However, further research on the use of influenza-specific PROs in routine care settings is needed. Based on these findings, we describe opportunities and challenges for PROs and propose recommendations to facilitate wider implementation of PROs in influenza research and patient care.