Table 3.

Patients discharged with a diagnosis of COPD: hazard ratios (HRs) with 95% CI for overall mortality estimated by Cox regression

Population features	Overall cohort		Patients aged 45–84 years
	HR (CI)	P-value	HR (CI)	P-value
Age, years	1.07 (1.06–1.07)	<0.001	1.06 (1.06–1.06)	<0.001
Females vs males	0.76 (0.73–0.78)	<0.001	0.74 (0.71–0.77)	<0.001
Severity score 1 vs 0	1.39 (1.34–1.44)	<0.001	1.45 (1.40–1.51)	<0.001
Severity score 2 vs 0	1.69 (1.57–1.82)	<0.001	1.83 (1.68–1.99)	<0.001
Charlson 1 vs 0	1.31 (1.26–1.36)	<0.001	1.39 (1.32–1.45)	<0.001
Charlson 2 vs 0	1.57 (1.50–1.64)	<0.001	1.70 (1.61–1.80)	<0.001
Charlson 3+ vs 0	1.84 (1.74–1.95)	<0.001	1.99 (1.86–2.13)	<0.001
CKD	1.36 (1.30–1.42)	<0.001	1.41 (1.33–1.50)	<0.001

Notes: Severity score was defined by none, one, or both of the following criteria: an hospital diagnosis or an exemption from medical charges due to respiratory failure; previous hospitalizations for COPD. Modified Charlson index: the modified version of the Charlson Comorbidity Index (CCI) adapted to ICD-9-CM codes was adopted based on diseases reported during hospitalizations.

Abbreviations: HR, hazard ratio; CI, confidence interval; CKD, chronic kidney disease; ICD-9-CM, International Classification of Diseases, 9th Revision, Clinical Modification.