Table S2.

Subgroup analysis of the risk of chronic obstructive pulmonary disease (COPD)-related health-care utilization during a 5-year period according to the forced expiratory volume in 1 s (FEV₁)

IRR (95% CI)	BMI (kg/m2)				P for trend
	<18.5	18.5–22.9	23–24.9	≥25
FEV1 ≥80% predicted
Crude IRR
Hospitalization	7.20 (0.20–265.07)	Reference	1.24 (0.33–4.66)	0.57 (0.14–2.32)	0.33
Outpatient clinic visits	0.52 (0.28–0.96)		1.04 (0.85–1.26)	0.89 (0.72–1.10)	0.11
Pharmacy use	0.33 (0.15–0.73)		1.04 (0.79–1.37)	0.90 (0.67–1.19)	0.08
Adjusted IRRa
Hospitalization	10.04 (0.29–348.56)		1.08 (0.30–3.92)	0.58 (0.14–2.38)	0.20
Outpatient clinic visits	0.45 (0.24–0.82)		1.05 (0.87–1.27)	0.97 (0.79–1.19)	0.05
Pharmacy use	0.27 (0.12–0.59)		1.05 (0.80–1.36)	1.00 (0.76–1.33)	0.03
Adjusted IRRb
Hospitalization	12.22 (0.37–402.38)		1.25 (0.34–4.58)	0.61 (0.15–2.40)	0.15
Outpatient clinic visits	0.45 (0.24–0.82)		1.05 (0.87–1.27)	0.97 (0.79–1.19)	0.05
Pharmacy use	0.28 (0.20–0.38)		1.08 (1.01–1.15)	0.99 (0.92–1.07)	<0.01
50%≤ FEV1<80% predicted
Crude IRR
Hospitalization	2.57 (0.15–42.62)	Reference	1.70 (0.50–5.77)	0.84 (0.27–2.63)	0.63
Outpatient clinic visits	1.58 (0.98–2.55)		0.86 (0.70–1.07)	0.73 (0.59–0.89)	<0.01
Pharmacy use	1.53 (0.79–2.96)		0.78 (0.59–1.04)	0.64 (0.49–0.84)	<0.01
Adjusted IRRa
Hospitalization	2.68 (0.18–40.95)		1.36 (0.41–4.48)	1.21 (0.39–3.73)	0.86
Outpatient clinic visits	1.22 (0.79–1.90)		0.89 (0.72–1.09)	0.86 (0.71–1.05)	0.25
Pharmacy use	1.14 (0.61–2.14)		0.83 (0.63–1.09)	0.78 (0.60–1.01)	0.22
Adjusted IRRb
Hospitalization	3.14 (0.21–46.92)		1.64 (0.49–5.54)	1.37 (0.44–4.21)	0.73
Outpatient clinic visits	1.21 (0.78–1.87)		0.86 (0.70–1.05)	0.85 (0.70–1.03)	0.16
Pharmacy use	1.11 (1.00–1.23)		0.79 (0.75–0.84)	0.73 (0.69–0.78)	<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; FEV₁, forced expiratory volume in 1 s.