Table 2

Relation between clinical, radiological, and physiological parameters in patients with idiopathic pulmonary alveolar proteinosis (iPAP)

Variables	LDH		Pao₂*		AaPo₂*
Variables	Correlation coefficient	p value	Correlation coefficient	p value	Correlation coefficient	p value
LDH, lactate dehydrogenase; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; TLC, total lung capacity; Tlco, carbon monoxide transfer factor; HRCT, high resolution computed tomography.
*Pao₂ and AaPo₂ were measured in the sitting position at room air.
AaPo₂ = Pao₂ – Pao₂; Pao₂ = (barometric pressure − 47) × Fio₂ − Paco₂/0.8.
FEV₁ (% pred)	−0.10	0.775	0.24	0.426	−0.38	0.197
FVC (% pred)	−0.17	0.571	0.35	0.247	−0.47	0.108
TLC (% pred)	−0.39	0.190	0.51	0.078	−0.51	0.076
Tlco (% pred)	−0.51	0.076	0.36	0.231	−0.61	0.027
Radiographs
Opacity score	0.41	0.169	−0.59	0.033	0.53	0.062
Extent score	0.56	0.045	−0.48	0.096	0.59	0.035
Severity score	0.56	0.045	−0.57	0.040	0.60	0.033
Chest HRCT
Opacity score	0.54	0.056	−0.51	0.072	0.36	0.232
Extent score	0.77	0.002	−0.57	0.042	0.64	0.019
Severity score	0.56	0.045	−0.60	0.032	0.60	0.029
Reticulation score	0.75	0.003	−0.57	0.042	0.56	0.047