Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Observational Study
. 2018 Feb;21(2):210-218.
doi: 10.1016/j.jval.2017.04.014. Epub 2017 Jun 7.

Reliability, Validity, and Responsiveness of InFLUenza Patient-Reported Outcome (FLU-PRO©) Scores in Influenza-Positive Patients

Affiliations
Observational Study

Reliability, Validity, and Responsiveness of InFLUenza Patient-Reported Outcome (FLU-PRO©) Scores in Influenza-Positive Patients

John H Powers 3rd et al. Value Health. 2018 Feb.

Abstract

Objectives: To assess the reliability, validity, and responsiveness of InFLUenza Patient-Reported Outcome (FLU-PRO©) scores for quantifying the presence and severity of influenza symptoms.

Methods: An observational prospective cohort study of adults (≥18 years) with influenza-like illness in the United States, the United Kingdom, Mexico, and South America was conducted. Participants completed the 37-item draft FLU-PRO daily for up to 14 days. Item-level and factor analyses were used to remove items and determine factor structure. Reliability of the final tool was estimated using Cronbach α and intraclass correlation coefficients (2-day reliability). Convergent and known-groups validity and responsiveness were assessed using global assessments of influenza severity and return to usual health.

Results: Of the 536 patients enrolled, 221 influenza-positive subjects comprised the analytical sample. The mean age of the patients was 40.7 years, 60.2% were women, and 59.7% were white. The final 32-item measure has six factors/domains (nose, throat, eyes, chest/respiratory, gastrointestinal, and body/systemic), with a higher order factor representing symptom severity overall (comparative fit index = 0.92; root mean square error of approximation = 0.06). Cronbach α was high (total = 0.92; domain range = 0.71-0.87); test-retest reliability (intraclass correlation coefficient, day 1-day 2) was 0.83 for total scores and 0.57 to 0.79 for domains. Day 1 FLU-PRO domain and total scores were moderately to highly correlated (≥0.30) with Patient Global Rating of Flu Severity (except nose and throat). Consistent with known-groups validity, scores differentiated severity groups on the basis of global rating (total: F = 57.2, P < 0.001; domains: F = 8.9-67.5, P < 0.001). Subjects reporting return to usual health showed significantly greater (P < 0.05) FLU-PRO score improvement by day 7 than did those who did not, suggesting score responsiveness.

Conclusions: Results suggest that FLU-PRO scores are reliable, valid, and responsive to change in influenza-positive adults.

Keywords: influenza; patient-reported outcome; psychometric; reliability; responsiveness; validity.

PubMed Disclaimer

Figures

Figure 1
Figure 1. Final FLU-PRO Conceptual Framework
Figure 2
Figure 2. FLU-PRO Domain and Total Score by Diary Days 1 to 14

References

    1. Centers for Disease Control and Prevention (CDC) Seasonal Influenza (Flu) in the Workplace. [cited 2015 June 1]; Available from: http://www.cdc.gov/niosh/topics/flu/
    1. Centers for Disease Control and Prevention (CDC) Seasonal Influenza (Flu) [cited 2016 January 28]; Available from: http://www.cdc.gov/flu/about/disease/index.htm.
    1. Centers for Disease Control and Prevention (CDC) Key Facts about Influenza (Flu) & Flu Vaccine. [cited 2016 January 28]; Available from: http://www.cdc.gov/flu/keyfacts.htm.
    1. World Health Organization (WHO) Influenza (Seasonal): Fact sheet N°211. [cited 2015 June 1];2014 Available from: http://www.who.int/mediacentre/factsheets/fs211/en/
    1. Osborne R, et al. Measurement of rapid changes in health outcomes in people with influenza symptoms. J Outcomes Res. 2000;4:15–30.

Publication types