Risk of anemia in morbidly obese patients after bariatric surgery in Taiwan

Table 2 Cox model with hazard ratio and 95% confidence intervals of anemia associated with receiving bariatric surgery among morbidly obese patients

Variable	Anemia	Crude1			Adjusted2
	No. (n = 221)	HR	(95%CI)	P value	HR	(95%CI)	P value
Receiving bariatric surgery
No	38	1.00	reference		1.00	reference
Yes	183	1.71	(1.2-2.44)	0.003	2.36	(1.52-3.65)	0.0001
Gender
Female	186	1.00	reference		1.00	reference
Male	35	0.32	(0.22-0.46)	< 0.0001	0.33	(0.23-0.48)	< 0.0001
Age
20-29 years	88	1.00	reference		1.00	reference
30-64 years	126	1.08	(0.82-1.41)	0.6028	1.06	(0.79-1.41)	0.6956
65-100 years	7	1.33	(0.61-2.88)	0.4724	1.33	(0.54-3.3)	0.5391
Comorbidities (ref = non-)
Hypertension	41	1.07	(0.76-1.51)	0.6837	1.43	(0.9-2.27)	0.1349
Hyperlipidemia	18	1.06	(0.65-1.71)	0.8249	1.14	(0.64-2.01)	0.6595
Diabetes mellitus	26	0.95	(0.63-1.44)	0.812	0.96	(0.59-1.57)	0.8826
Coronary artery disease	15	1.23	(0.73-2.08)	0.441	1.17	(0.61-2.25)	0.6403
Congestive heart failure	10	1.02	(0.54-1.93)	0.9436	0.91	(0.42-1.94)	0.8027
Stroke	4	0.63	(0.23-1.7)	0.3611	0.52	(0.18-1.5)	0.2286
Chronic kidney disease	7	1.32	(0.62-2.8)	0.4752	1.47	(0.66-3.28)	0.3504
Asthma	17	1.74	(1.06-2.85)	0.0293	1.85	(1.05-3.25)	0.034
Chronic obstructive pulmonary disease	6	0.93	(0.41-2.08)	0.8514	0.56	(0.22-1.43)	0.2267
Peripheral arterial occlusive disease	1	0.99	(0.14-7.05)	0.9905	1.47	(0.2-10.88)	0.705
Gastrointestinal ulcer	20	2.17	(1.37-3.44)	0.001	2.25	(1.34-3.77)	0.0021
Gastrointestinal bleeding	5	2.64	(1.09-6.42)	0.0321	1.83	(0.7-4.78)	0.2204

¹Crude HR: Represented relative hazard ratio.

²Adjusted HR: Represented adjusted hazard ratio: Mutually adjusted for sex, age, receiving bariatric surgery, and baseline comorbidities (as like tables) in Cox proportional hazard regression.