RT Journal Article
SR Electronic
T1 Factors predicting change in interpretation in PFTs when using FVC vs. the largest measured vital capacity
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP P2123
VO 44
IS Suppl 58
A1 Denitza Blagev
A1 Justin Dickerson
A1 Olinto Linares-Perdomo
A1 Dean Sorenson
A1 Alan Morris
YR 2014
UL http://erj.ersjournals.com/content/44/Suppl_58/P2123.abstract
AB BackgroundAlthough ERS/ATS guidelines recommend using the largest measured vital capacity, VCmax, the FVC is commonly used in PFT interpretations. 6% of PFTs in a large database of all comers have a change in PFT interpretation based on which vital capacity is used in the interpretation.ObjectiveTo determine which factors predict increased likelihood of an interpretive change when FVC or VCmax are used.Methods12,238 PFTs obtained as part of routine clinical care were interpreted using both FVC and VCmax and 6% (710) of interpretations were changed. We examined all variables using a logistic regression model reporting adjusted odds ratios. The model satisfying our diagnostic criteria, generating the highest c-statistic, and achieving the most parsimonious solution was used to determine which variables increased the odds of recategorization.ResultsCompared to no bronchodilator test, bronchodilator test with a positive response increased the odds of recategorization to 18 (CI 13-24), and even a lack of a bronchodilator response increased the odds of recategorization to 7 (CI 5-9). Larger FVCs decreased the odds of recategorization (0.68, CI 0.63-0.74). The number of tests performed did not increase the odds of recategorization.ConclusionBronchodilator testing and a positive bronchodilator response were the most likely to recategorize interpretations based on VCmax.