Table 2. Logistic regression analysis of potential risk factors for CIP developing.

CharacteristicsOR (95% CI)	Univariate analysis			Multivariate analysis
Age-at-treatment, year
<65	1 (ref)	NA
≥65	0.796 (0.311–2.036)	0.634
Gender
Male	1 (ref)	NA
Female	1.315 (0.403–4.293)	0.650
Smoking history
Never smoker	1 (ref)	NA
Anytime smoker	1.217 (0.458–3.234)	0.694
ECOG PS at initiation of ICI
0–1	1 (ref)	NA
≥2	1.343 (0.275–6.555)	0.715
COPD
No	1 (ref)	NA
Yes	3.460 (1.257–9.525)	0.016		7.194 (1.130–45.798)	0.037
Tumor histologic type
Adenocarcinoma	1 (ref)	NA
Squamous cell carcinoma	1.551 (0.561–4.291)	0.398
Other	1.822 (0.441–7.522)	0.407
PD-L1 expression status
<50%	1 (ref)	NA
≥50%	3.211 (1.090–9.458)	0.034		7.184 (1.154–44.721)	0.035
Peripheral blood cytokines
TNF (pg/mL)	1.021 (0.931–1.120)	0.657
IL-1β (pg/mL)	0.838 (0.470–1.496)	0.551
IL-2R (U/mL)	1.000 (0.999–1.001)	0.776
IL-6 (pg/mL)	1.006 (0.977–1.035)	0.691
IL-8 (pg/mL)	0.831 (0.691–0.999)	0.049		0.758 (0.587–0.978)	0.033
IL-10 (pg/mL)	1.095 (0.989–1.213)	0.082
Therapeutic regimen
Monotherapy	1 (ref)	NA
Combined chemotherapy	1.050 (0.394–2.796)	0.923
Treatment line
First-line	1 (ref)	NA
Second-line	1.020 (0.311–3.346)	0.974
Subsequent line	1.233 (0.416–3.651)	0.705

CIP, immune checkpoint inhibitor-related pneumonitis; OR, odds ratio; CI, confidence interval; ECOG PS, Eastern Cooperative Oncology Group performance status; ICI, immune checkpoint inhibitor; COPD, chronic obstructive pulmonary disease; PD-L1, programmed cell death-ligand 1; TNF, tumor necrosis factor; IL, interleukin.