TABLE 1.

Characteristics in never and ever users of metformin in the unmatched cohort and the matched cohort.

Variable	Unmatched cohort					Matched cohort
	Never users (n = 19,523)		Ever users (n = 152,347)		SD	Never users (n = 19,498)		Ever users (n = 19,498)		SD
	n	%	n	%		n	%	n	%
Demographic data
Age a (years)	68.32	13.34	64.11	11.94	−39.37	68.30	13.33	68.09	12.29	−1.09
Sex (men)	10,548	54.03	79,205	51.99	−4.11	10,537	54.04	10,430	53.49	−1.28
Occupation
I	7,039	36.05	56,816	37.29		7,032	36.07	7,010	35.95
II	3,249	16.64	32,363	21.24	13.52	3,246	16.65	3,273	16.79	0.25
III	4,814	24.66	35,482	23.29	−3.51	4,809	24.66	4,885	25.05	1.21
IV	4,421	22.65	27,686	18.17	−13.11	4,411	22.62	4,330	22.21	−0.89
Living region
Taipei	6,518	33.39	47,352	31.08		6,508	33.38	6,404	32.84
Northern	2,061	10.56	17,604	11.56	3.38	2,061	10.57	2,057	10.55	−0.04
Central	3,359	17.21	27,594	18.11	2.21	3,353	17.20	3,391	17.39	0.49
Southern	3,438	17.61	26,418	17.34	−0.56	3,435	17.62	3,447	17.68	0.40
Kao-Ping and Eastern	4,147	21.24	33,379	21.91	2.61	4,141	21.24	4,199	21.54	0.86
Major comorbidities
Hypertension	16,513	84.58	126,762	83.21	−5.14	16,489	84.57	16,474	84.49	−0.03
Dyslipidemia	13,461	68.95	123,784	81.25	33.25	13,452	68.99	13,535	69.42	0.92
Obesity	452	2.32	6,212	4.08	10.69	452	2.32	479	2.46	0.90
Diabetes-related complications
Nephropathy	7,173	36.74	43,358	28.46	−22.29	7,153	36.69	7,083	36.33	−1.15
Eye diseases	3,284	16.82	48,021	31.52	36.51	3,283	16.84	3,140	16.10	−2.60
Diabetic polyneuropathy	3,302	16.91	44,227	29.03	30.82	3,302	16.94	3,272	16.78	−0.78
Stroke	7,710	39.49	49,996	32.82	−18.19	7,689	39.43	7,562	38.78	−1.22
Ischemic heart disease	10,191	52.20	72,530	47.61	−11.73	10,175	52.18	10,001	51.29	−1.62
Peripheral arterial disease	4,864	24.91	40,714	26.72	2.95	4,854	24.89	4,733	24.27	−1.59
Antidiabetic drugs
Insulin	1,658	8.49	3,487	2.29	−34.88	1,641	8.42	1,489	7.64	−5.15
Sulfonylurea	14,157	72.51	109,708	72.01	8.27	14,155	72.60	14,649	75.13	4.77
Meglitinide	1,695	8.68	6,113	4.01	−21.47	1,689	8.66	1,681	8.62	−0.56
Acarbose	2,138	10.95	8,189	5.38	−19.59	2,131	10.93	2,301	11.80	0.79
Rosiglitazone	558	2.86	7,270	4.77	11.29	558	2.86	613	3.14	0.72
Pioglitazone	444	2.27	3,866	2.54	3.24	443	2.27	473	2.43	0.17
Commonly encountered comorbidities and potential risk factors
Chronic obstructive pulmonary disease	10,476	53.66	76,095	49.95	−10.34	10,454	53.62	10,478	53.74	0.45
Tobacco abuse	440	2.25	5,437	3.57	8.61	440	2.26	394	2.02	−1.70
Alcohol-related diagnoses	1,188	6.09	9,438	6.20	0.39	1,188	6.09	1,220	6.26	0.55
Cancer	1,822	9.33	11,224	7.37	−7.67	1,817	9.32	1,872	9.60	0.94
Heart failure	5,462	27.98	30,250	19.86	−24.05	5,449	27.95	5,267	27.01	−2.03
Parkinson’s Disease	1,120	5.74	5,625	3.69	−12.10	1,112	5.70	1,047	5.37	−1.30
Dementia	2,196	11.25	10,980	7.21	−19.61	2,508	12.86	2,364	12.12	−2.05
Head injury	730	3.74	6,034	3.96	1.18	729	3.74	691	3.54	−1.09
Valvular heart disease	2,791	14.30	15,552	10.21	−16.13	2,785	14.28	2,707	13.88	−1.05
Commonly used medications in diabetes patients
Angiotensin converting enzyme inhibitors/angiotensin receptor blockers	14,238	72.93	113,939	74.79	3.61	14,216	72.91	14,178	72.72	−0.38
Calcium channel blockers	13,118	67.19	94,952	62.33	−12.16	13,099	67.18	13,036	66.86	−0.43
Statins	10,002	51.23	98,120	64.41	30.28	9,999	51.28	9,958	51.07	−0.66
Fibrates	6,239	31.96	63,635	41.77	23.11	6,237	31.99	6,161	31.60	−0.84
Aspirin	11,985	61.39	96,528	63.36	2.65	11,966	61.37	12,019	61.64	0.70

^aAge is expressed as mean and standard deviation.

Refer to “Materials and Methods” for the classification of occupation.

SD: standardized difference.