Table 3. Factors Associated With Progression-Free Survival After Programmed Cell Death 1 Inhibitor Treatment.

Characteristic or SCFA	HR (95% CI)	P value
Age, y
<65	1 [Reference]	.91
≥65	1.03 (0.56-1.89)
Sex
Male	1 [Reference]	.39
Female	0.76 (0.41-1.40)
Body mass indexa
<22	1 [Reference]	.22
≥22	0.67 (0.36-1.26)
Primary cancer
Melanoma	1 [Reference]	.30
Nonmelanoma	1.37 (0.75-2.51)
No. of organ metastases
<3	1 [Reference]	.46
≥3	1.30 (0.64-2.65)
Fecal concentration, μmol/g
Acetic acid
<270	1 [Reference]	<.001
≥270	0.29 (0.15-0.54)
Propionic acid
<90	1 [Reference]	<.001
≥90	0.08 (0.03-0.20)
Butyric acid
<40	1 [Reference]	<.001
≥40	0.31 (0.16-0.60)
Isobutyric acid
<30	1 [Reference]	.50
≥30	0.80 (0.41-1.54)
Valeric acid
<15	1 [Reference]	.04
≥15	0.53 (0.29-0.98)
Isovaleric acid
<20	1 [Reference]	.40
≥20	0.76 (0.40-1.43)
Hydroangelic acid
<17	1 [Reference]	.62
≥17	0.85 (0.46-1.58)
Caproic acid
<2	1 [Reference]	.08
≥2	0.46 (0.19-1.11)
Succinic acid
<9	1 [Reference]	.94
≥9	0.97 (0.53-1.77)
Plasma concentration, μmol/g
3-Indoleacetic acid
<1.35	1 [Reference]	.56
≥1.35	0.79 (0.36-1.74)
Propionic acid
<6	1 [Reference]	.09
≥6	0.59 (0.32-1.08)
Butyric acid
<1.25	1 [Reference]	.82
≥1.25	0.93 (0.51-1.70)
Isobutyric acid
<2.55	1 [Reference]	.12
≥2.55	0.62 (0.34-1.14)
Valeric acid
<0.1	1 [Reference]	.72
≥0.1	1.17 (0.46-2.97)
Isovaleric acid
<0.15	1 [Reference]	.04
≥0.15	0.38 (0.14-0.99)
Hydroangelic acid
<0.15	1 [Reference]	.36
≥0.15	0.65 (0.26-1.63)
Caproic acid
<1.15	1 [Reference]	.57
≥1.15	0.79 (0.36-1.74)
Succinic acid
<2	1 [Reference]	.12
≥2	2.07 (0.82-5.18)

Abbreviations: HR, hazard ratio; SCFA, short-chain fatty.

^aCalculated as weight in kilograms divided by height in meters squared.