Fig 1.
Study flow chart describing the study enrolment process.
CRF, chronic respiratory failure.
Table 1.
Comparison of background characteristics between patients who did (CRF group) and did not develop CRF (non-CRF group).
Table 2.
Comparison of longitudinal changes in arterial blood gas analyses and pulmonary function tests between patients who did (CRF group) and did not develop CRF (non-CRF group).
Fig 2.
Long-term trajectories of ABG parameters.
(a) PaO2, PaCO2, and A-aDO2 in the CRF group. There was a gradual increase in A-aDO2 and decreases in both PaO2 and PaCO2 over the course of ten years. (b) PaO2, PaCO2, and A-aDO2 in the non-CRF group. There were no apparent changes in any parameter over ten years. A-aDO2, alveolar-arterial oxygen gradient; ABG, arterial blood gas; CRF, chronic respiratory failure; PaCO2, partial pressure of carbon dioxide; PaO2, partial arterial pressure of oxygen.
Table 3.
Change in A-aDO2 from baseline in each year among the CRF group and the non-CRF group.
Table 4.
Multivariate Cox proportional hazards analysis for predicting CRF development.
Fig 3.
Long-term changes in ABG parameters retrospectively tracked from the initiation of LTOT in the CRF group.
From five years prior to the initiation of LTOT, a decrease in PaO2 and PaCO2, accompanied by an increase in A-aDO2, was observed. This trend significantly differed from that of the non-CRF group and was most prominent for A-aDO2. A-aDO2, alveolar-arterial oxygen gradient; ABG, arterial blood gas; CRF, chronic respiratory failure; LTOT, long-term oxygen therapy; PaCO2, partial pressure of carbon dioxide; PaO2, partial arterial pressure of oxygen. *P<0.05, †P<0.005, ‡P<0.001, §P<0.0001.