Table 5.

Risk of chronic obstructive pulmonary disease (COPD)-related health-care utilization during a 5-year period

BMI (kg/m2) group	Crude IRR (95% CI)			Adjusted IRRa (95% CI)			Adjusted IRRb (95% CI)
	Hospitalization	Outpatient clinic visits	Pharmacy use	Hospitalization	Outpatient clinic visits	Pharmacy use	Hospitalization	Outpatient clinic visits	Pharmacy use
<18.5	4.65 (0.46–47.03)	1.22 (0.73–1.98)	1.19 (0.72–1.96)	4.93 (0.52–46.38)	0.83 (0.52–1.34)	0.82 (0.51–1.33)	7.12 (0.77–66.02)	0.82 (0.51–1.32)	0.90 (0.82–0.99)
18.5–22.9	Reference
23–24.9	1.17 (0.46–2.96)	0.89 (0.73–1.09)	0.87 (0.71–1.06)	1.02 (0.42–2.50)	0.95 (0.78–1.15)	0.93 (0.76–1.12)	1.26 (0.50–3.16)	0.95 (0.79–1.15)	0.92 (0.88–0.96)
≥25	0.70 (0.28–1.75)	0.73 (0.60–0.89)	0.73 (0.60–0.89)	0.79 (0.33–1.94)	0.87 (0.72–1.05)	0.87 (0.72–1.05)	1.02 (0.41–2.52)	0.87 (0.72–1.06)	0.82 (0.79–0.86)
P for trend	0.25	0.01	0.01	0.25	0.50	0.48	0.01	0.52	<0.01

Notes:

^aAdjusted by age, sex, and FEV₁ (%).

^bAdjusted by age, sex, smoking pack-year, and FEV₁ (%).

Abbreviations: IRR, incidence rate ratio; BMI, body mass index.