Table 2.

Incidence and risk of atrial fibrillation according to the presence of anemia.

Anemia	AF cases	Person-years	AF incidence*	Model 1 HR (95% CI)	Model 2 HR (95% CI)	Model 3 HR (95% CI)	Model 4 HR (95% CI)	Model 5 HR (95% CI)
No	158,698	50,285,632	3.156	1.00 (reference)	1.00 (reference)	1.00 (reference)	1.00 (reference)	1.00 (reference)
Yes	28,504	6,499,799	4.39	1.39 (1.38–1.41)†	1.08 (1.06–1.09)†	1.13 (1.11–1.14)†	1.11(1.10–1.12)†	1.06 (1.05–1.08)†

AF indicates atrial fibrillation; CI, confidence interval; HR, hazard ratio.

*Incidence rates were calculated per 1,000 person-years. ^†P < 0.001

Model 1: Cox proportional hazards model without adjustment. Model 2: Model 1 with adjustment for age and sex. Model 3: Model 2 with additional adjustment for body mass index, smoking, alcohol consumption, exercise frequency, and low income. Model 4: Model 3 with additional adjustment for hypertension, diabetes, and dyslipidemia. Model 5: Model 4 with additional adjustment for ischemic heart disease, congestive heart failure, stroke, chronic obstructive pulmonary disease, estimated creatinine clearance, obstructive sleep apnea, and thyroid disease.