PLoS ONE (Jan 2018)

Performance of the inFLUenza Patient-Reported Outcome (FLU-PRO) diary in patients with influenza-like illness (ILI).

  • John H Powers,
  • Elizabeth D Bacci,
  • Nancy K Leidy,
  • Jiat-Ling Poon,
  • Sonja Stringer,
  • Matthew J Memoli,
  • Alison Han,
  • Mary P Fairchok,
  • Christian Coles,
  • Jackie Owens,
  • Wei-Ju Chen,
  • John C Arnold,
  • Patrick J Danaher,
  • Tahaniyat Lalani,
  • Timothy H Burgess,
  • Eugene V Millar,
  • Michelande Ridore,
  • Andrés Hernández,
  • Patricia Rodríguez-Zulueta,
  • Hilda Ortega-Gallegos,
  • Arturo Galindo-Fraga,
  • Guillermo M Ruiz-Palacios,
  • Sarah Pett,
  • William Fischer,
  • Daniel Gillor,
  • Laura Moreno Macias,
  • Anna DuVal,
  • Richard Rothman,
  • Andrea Dugas,
  • M Lourdes Guerrero

DOI
https://doi.org/10.1371/journal.pone.0194180
Journal volume & issue
Vol. 13, no. 3
p. e0194180

Abstract

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BackgroundThe inFLUenza Patient Reported Outcome (FLU-PRO) measure is a daily diary assessing signs/symptoms of influenza across six body systems: Nose, Throat, Eyes, Chest/Respiratory, Gastrointestinal, Body/Systemic, developed and tested in adults with influenza.ObjectivesThis study tested the reliability, validity, and responsiveness of FLU-PRO scores in adults with influenza-like illness (ILI).MethodsData from the prospective, observational study used to develop and test the FLU-PRO in influenza virus positive patients were analyzed. Adults (≥18 years) presenting with influenza symptoms in outpatient settings in the US, UK, Mexico, and South America were enrolled, tested for influenza virus, and asked to complete the 37-item draft FLU-PRO daily for up to 14-days. Analyses were performed on data from patients testing negative. Reliability of the final, 32-item FLU-PRO was estimated using Cronbach's alpha (α; Day 1) and intraclass correlation coefficients (ICC; 2-day reproducibility). Convergent and known-groups validity were assessed using patient global assessments of influenza severity (PGA). Patient report of return to usual health was used to assess responsiveness (Day 1-7).ResultsThe analytical sample included 220 ILI patients (mean age = 39.3, 64.1% female, 88.6% white). Sixty-one (28%) were hospitalized at some point in their illness. Internal consistency reliability (α) of FLU-PRO Total score was 0.90 and ranged from 0.72-0.86 for domain scores. Reproducibility (Day 1-2) was 0.64 for Total, ranging from 0.46-0.78 for domain scores. Day 1 FLU-PRO scores correlated (≥0.30) with the PGA (except Gastrointestinal) and were significantly different across PGA severity groups (Total: F = 81.7, pConclusionsResults suggest FLU-PRO scores are reliable, valid, and responsive in adults with influenza-like illness.