Serum bilirubin and the risk of chronic obstructive pulmonary disease exacerbations

Respiratory Research

Table 4 MACRO validation cohort model. Time-dependent multivariable Cox proportional hazards analyses for risk of acute exacerbation of chronic obstructive pulmonary disease (AECOPD) and bilirubin prior to first AECOPD

Parameter	aHR	95% CI	p-value
MACRO Validation Cohort Model
Treatment assignment	0.73	0.63–0.86	<0.001
Male sex	0.78	0.66–0.91	0.002
Black race	1.01	0.80–1.27	0.95
BMI (kg/m²)	0.99	0.98–1.00	0.07
Chronic bronchitis	1.22	1.03–1.44	0.02
Supplemental oxygen use	1.29	1.09–1.53	0.003
SGRQ score	1.01	1.00–1.01	0.003
Inhaler use^a - none (0 of 3 classes: LABA, LAMA, ICS)	0.74	0.54–1.03	0.20
Inhaler use^a - 1 of 3 classes	0.84	0.66–1.07	0.71
Inhaler use^a - 2 of 3 classes	0.91	0.76–1.09	0.52
Steroid or antibiotic use in year prior to enrollment	1.64	1.28–2.10	<0.001
BILIRUBIN (per log ₁₀ increase)	0.80	0.67–0.94	0.008

Abbreviations: BMI body mass index, ICS inhaled corticosteroid, LABA long-acting beta agonist, LAMA long-acting antimuscarinic, SGRQ St. George’s Respiratory Questionnaire
^aReferent group is 3-class inhaler therapy (long-acting beta agonist, long-acting antimuscarinic, and inhaled corticosteroid)
Bilirubin is presented in bold, as this was the primary predictor variable

ISSN: 1465-993X