Table 4.

Adjusted HR for depression after cholecystectomy as related to follow-up periods

Follow-up period	n	Event	aHR (95% CI)	P value
2 yr (13–24 mo)
Control	223,868	5,581	1 (Ref.)	<0.0001
Cholecystectomy	111,934	3,940	1.392 (1.336, 1.45)	<0.0001
3 yr (25–36 mo)
Control	216,646	5,020	1 (Ref.)	<0.0001
Cholecystectomy	106,491	3,332	1.335 (1.277, 1.395)	<0.0001
4 yr (37–48 mo)
Control	175,385	4,073	1 (Ref.)	<0.0001
Cholecystectomy	84,942	2,555	1.272 (1.21, 1.337)	<0.0001
≥ 5 yr (≥49 mo)
Control	136,079	6,727	1 (Ref.)	<0.0001
Cholecystectomy	65,148	4,195	1.303 (1.253, 1.354)	<0.0001

Multivariate model adjusted for age, sex, income, place of residence, diabetes mellitus, hypertension, and dyslipidemia.

aHR, adjusted hazard ratio; CI, confidence interval.