Quality control of spirometry: a lesson from the BRONCUS trial.
This report describes the quality control programme used within the Bronchitis Randomized on N-acetylcysteine (NAC) Cost-Utility Study, a trial designed to assess the decline in lung function, exacerbation rate, health status, and cost-effectiveness with NAC or a placebo in 523 patients with chronic obstructive pulmonary disease over a 3-yr period. Spirometry was scored from 0 (worst quality) to 6 (best quality). The mean score of 314 spirometries from 243 patients evaluated during the trial was 5.63+/-0.83. Linear regression analysis of the scores of 47 participating centres plotted against the time at which spirometries were performed yielded an intercept of 5.7+/-0.5 and a slope of -0.0001+/-0.001, which suggests that the initial high quality was maintained over time. Retrospective examination of a further 345 postbronchodilator spirometries from 208 patients with a forced expiratory volume at one second exceeding the mean individual value recorded over the study in excess of 20% revealed a slightly lower quality of the start-of-test manoeuvre compared with the 314 spirometries. In conclusion, these findings would suggest that the quality control programme is likely to have helped achieve and maintain long-term spirometry performance in the Bronchitis Randomized on N-acetylcysteine (NAC) Cost-Utility Study trial. Special care should be paid to the spirometries whose forced expiratory volume in one second values exceed the mean value.
Pellegrino
R
R
Centro di Fisiopatologia Respiratoria e di Studio della Dispnea, Azienda Ospedaliera S. Croce e Carle, 12100 Cuneo, Italy. pellegrino.r@ospedale.cuneo.it
Decramer
M
M
van Schayck
C P O
CP
Dekhuijzen
P N R
PN
Troosters
T
T
van Herwaarden
C
C
Olivieri
D
D
Del Donno
M
M
De Backer
W
W
Lankhorst
I
I
Ardia
A
A
D000111:Acetylcysteine / Q000627:therapeutic use*; D000368:Aged; D018450:Disease Progression; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000188:drug therapy*; D011786:Quality Control; D012016:Reference Values; D012129:Respiratory Function Tests; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013147:Spirometry / Q000379:methods*
D000111:Acetylcysteine