Reliability and Validity of the Brief Fatigue Inventory and Dyspnea Inventory in People With Chronic Obstructive Pulmonary Disease

Abstract

Context: Dyspnea, fatigue, and pain are common in individuals with chronic obstructive pulmonary disease (COPD). However, questionnaires with a similar format are not available to assess their relative severity and interference.

Objectives: To determine the reliability and validity of the Brief Fatigue Inventory (BFI) and Dyspnea Inventory (DI) in COPD patients who attend pulmonary rehabilitation programs.

Methods: Participants were recruited from four pulmonary rehabilitation programs to complete a survey package containing: the Chronic Respiratory Questionnaire (CRQ), BFI, and DI; and one week later, to complete the BFI and DI. Retrospective data of the CRQ, BFI, and DI were retrieved from one of the programs.

Results: For the prospective component, there was an 85% response rate (n = 91) for the first package and 83.5% response rate (n = 76) for the second package. Retrospectively, CRQ, BFI, and DI data were retrieved from 48 charts. The BFI and DI demonstrated excellent internal consistency (Cronbach alpha = 0.96 both), and high test-retest reliability (intraclass correlation3,1 = 0.86 and 0.91, respectively). By comparison to the fatigue and dyspnea domains of the CRQ, the BFI showed high concurrent validity (ρ = -0.83), whereas the DI showed moderate (ρ = -0.57) to high (ρ = -0.78) concurrent validity. Factor analysis provided evidence that the items in the BFI and DI measured the intended constructs.

Conclusion: The BFI and DI are valid and reliable measures to evaluate fatigue and dyspnea in COPD patients and could be used concurrently with the Brief Pain Inventory to inform the relative severity and interference of these common symptoms in COPD.

Keywords: Chronic obstructive pulmonary disease; dyspnea; fatigue; reliability; validity.