TABLE 6.

Sample attrition and data continuity among patients with type 2 diabetes mellitus in the National Cheng Kung University Hospital electronic health record database.

	Initial sample size, n = 23,719
	Step 1: Number of patients eligible for analysis	Sample retention from initial sample to Step 1 (%)	Step 2: Number of patients with continuous baseline and/or follow-up data	Sample retention from Step 1 to Step 2 (%)	Overall sample retention from initial sample to Step 2 (%)
Baseline only
At least 6-months baseline	22,962	97	22,962	64	62
At least 12-months baseline	22,117	93	22,117	58	54
Follow-up only
At least 12-months follow-up	21,486	91	21,486	82	74
At least 24-months follow-up	19,025	80	19,025	73	58
At least 60-months follow-up	11,668	49	11,668	62	30
Baseline + Follow-up
At least 6-months baseline + at least 24-months follow-up	18,212	77	18,212	55	42
At least 12-months baseline + at least 24-months follow-up	17,304	73	17,304	54	39