Table 3.

Adjusted Hazard Ratios of Mortality in Subpopulations Treated With Metformin.

Stratified Variables	Metformin
	User			Nonuser			Reference: nonuser
	Patients	Death	%	Patients	Death	%	HRa	95% CI	P
Sex
Female	196	85	43.4%	653	414	63.4%	0.66	0.52-0.84	.0006*
Male	177	111	62.7%	607	467	76.9%	0.80	0.65-0.99	.0442*
Age (years)
40-64	129	66	51.2%	428	288	67.3%	0.79	0.60-1.05	.102
≥65	244	130	53.3%	832	593	71.3%	0.71	0.59-0.86	.0006*
Hypertension
Without	81	45	55.6%	360	258	71.7%	0.70	0.50-0.97	.0311*
With	292	151	51.7%	900	623	69.2%	0.75	0.63-0.90	.002*
Stroke
Without	284	150	52.8%	897	615	68.6%	0.75	0.63-0.90	.0023*
With	89	46	51.7%	363	266	73.3%	0.63	0.45-0.87	.0047*
CAD
Without	231	128	55.4%	746	519	69.6%	0.76	0.62-0.92	.0055*
With	142	68	47.9%	514	362	70.4%	0.70	0.53-0.91	.0083*
COPD
Without	262	137	52.3%	759	520	68.5%	0.74	0.61-0.89	.0016*
With	111	59	53.2%	501	361	72.1%	0.71	0.54-0.95	.0195*
Renal insufficiency
Without	365	194	53.2%	1194	838	70.2%	0.74	0.63-0.87	.0002*
With	8	2	25.0%	66	43	65.2%	0.10	0.02-0.55	.0085*
Smoking-related disorder
Without	309	156	50.5%	929	634	68.2%	0.72	0.60-0.86	.0002*
With	64	40	62.5%	331	247	74.6%	0.79	0.55-1.13	.190
CT/RT
CCRT	135	88	65.2%	566	445	78.6%	0.79	0.62-1.00	.0457*
CT	129	67	51.9%	409	269	65.8%	0.75	0.57-0.98	.0383*
RT	34	15	44.1%	102	79	77.5%	0.46	0.25-0.84	.0118*
Without CT or RT	75	26	34.7%	183	88	48.1%	0.79	0.50-1.25	.308
EGFR-TKI
Gefitinib	215	103	47.9%	633	422	66.7%	0.64	0.51-0.79	<.001*
Erlotinib	129	84	65.1%	487	380	78.0%	0.82	0.64-1.04	.100
Both	29	9	31.0%	140	79	56.4%	0.44	0.21-0.94	.0343*
EGFR-TKI response
Responder	239	91	38.1%	737	434	58.9%	0.62	0.49-0.78	<.001*
Nonresponder	134	105	78.4%	523	447	85.5%	0.85	0.69-1.06	.143
CT regimens before EGFR-TKI
≤1	261	116	44.4%	848	542	63.9%	0.67	0.54-0.82	<.001*
Gefitinib (adenocarcinoma)	194	72	37.1%	574	340	59.2%	0.59	0.46-0.77	<.001*
Erlotinib (adenocarcinoma)	67	44	65.7%	274	202	73.7%	0.81	0.57-1.14	.223
≥2	112	80	71.4%	412	339	82.3%	0.87	0.68-1.12	.290
Gefitinib (adenocarcinoma)	48	40	83.3%	178	154	86.5%	0.98	0.68-1.41	.894
Erlotinib (NSCLC)	64	40	62.5%	234	185	79.1%	0.82	0.57-1.17	.265

Abbreviations: HR, hazard ratio; CI, confidence interval; CAD, coronary artery disease; COPD, chronic obstructive pulmonary disease; CT, chemotherapy; RT, radiotherapy; CCRT, concurrent chemoradiotherapy; EGFR-TKI, epidermal growth factor receptor-tyrosine kinase inhibitor; NSCLC, non-small-cell lung cancer.

^aHRs were adjusted for sex, age, urbanization, income, hypertension, stroke, CAD, COPD, renal insufficiency, smoking-related disorders, CT/RT, CT regimens used before EGFR-TKI therapy.

^*P < .05.