PURPOSE: The purpose of this study was to examine the responsiveness of three self-reported instruments to measure dyspnea related to activities of daily living over two years in symptomatic patients treated for COPD. Our hypothesis was that the three dyspnea instruments, the self-administered and computerized (SAC) transition dyspnea index (TDI) (range, -9 to +9), the modified Medical Research Council (MRC) scale (range, 0 to 4), and the University of California San Diego (UCSD) shortness of breath questionnaire (range, 0 to 120), would demonstrate significant worsening in dyspnea over two years.
METHODS: Observational cohort study of symptomatic patients with COPD evaluated at an initial visit and every six months over two years at an academic institution. The three dyspnea instruments were administered in random order prior to pulmonary function testing. Inclusion criteria were diagnosis of COPD with FEV1/FVC < 70% and dyspnea during activities. Exclusion criteria were clinically significant co-morbid disease or current substance abuse.
RESULTS: At initial visit, the 70 patients (female = 37; male = 33) had post-bronchodilator FEV1 = 1.53 ± 0.76 l (48 ± 18 %pred), SAC baseline dyspnea index was 5.8 ± 2.3, mMRC was 2.1 ± 1.0, and UCSD was 53.6 ± 21.5. Dyspnea scores of the 43 patients who completed testing at 2 years were: SAC TDI = - 0.93 ± 2.7; mMRC = 2.0 ± 1.0; and UCSD = 59.3 ± 24.8. Using fixed effects regression modeling, there were significant changes in the SAC TDI (p = 0.03; CI: - 0.07 to -0.004) and the UCSD questionnaire (p =0.001; CI: 0.167 to 0.570), but not the mMRC (p = 0.52; CI: - 0.009 to 0.017) over two years. Although changes were noted for post-bronchodilator FEV1 and FVC, these measures did not increase or decrease consistently over time [FEV1 %pred (p = 0.09; CI: -0.199 to 0.014); FVC %pred (p = 0.65; CI: -0.223 to 0.140)].
CONCLUSIONS: We conclude that the two multidimensional instruments, the SAC TDI and the UCSD shortness of breath questionnaire, demonstrated progression of breathlessness with activities over two years, whereas the unidimensional mMRC scale did not reflect worsening of dyspnea. Lung function was generally stable over the two year period.
CLINICAL IMPLICATIONS: The SAC TDI and the UCSD shortness of breath questionnaire were responsive over two years. Both instruments are recommended to quantify breathlessness related to physical activities over time in patients with symptomatic COPD.
DISCLOSURE: John Baird: University grant monies: Scientific Director of Psychological Applications
The following authors have nothing to disclose: Donald Mahler, Joseph Ward, Laurie Waterman
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