Table 1.
Study subjects at baseline: demographics, severity of disease, and associated comorbidities
| Population features | 45–64 years (n=2,537) (%) |
65–74 years (n=5,984) (%) |
75–84 years (n=11,817) (%) |
≥85 years (n=6,934) (%) |
All patients (n=27,272) (%) |
|---|---|---|---|---|---|
| Male gender | 68.7 | 69.3 | 62.9 | 46.5 | 60.7 |
| Severity score | |||||
| 0 | 67.6 | 65.4 | 66.7 | 72.4 | 68.0 |
| 1 | 29.7 | 30.6 | 29.4 | 25.2 | 28.6 |
| 2 | 2.7 | 4.0 | 3.9 | 2.4 | 3.4 |
| Modified Charlson index | |||||
| 0 | 44.9 | 35.3 | 30.2 | 30.5 | 32.8 |
| 1 | 35.2 | 36.9 | 39.1 | 40.6 | 38.6 |
| 2 | 14.1 | 18.9 | 21.5 | 20.9 | 20.1 |
| ≥3 | 5.8 | 9.0 | 9.3 | 8.0 | 8.6 |
| Selected comorbidities | |||||
| CKD | 4.3 | 8.1 | 10.5 | 13.6 | 10.2 |
| Heart failure | 11.9 | 18.9 | 26.1 | 32.6 | 24.9 |
| Ischemic heart disease | 8.3 | 9.9 | 9.0 | 7.6 | 8.8 |
| Cerebrovascular diseases | 4.5 | 8.1 | 11.3 | 12.3 | 10.2 |
| Peripheral arterial disease | 6.0 | 8.6 | 8.5 | 5.4 | 7.5 |
| Diabetes | 24.3 | 25.9 | 23.7 | 20.2 | 23.4 |
| Neoplasms | 16.8 | 23.6 | 22.8 | 15.7 | 20.6 |
| Dementia | 0.4 | 1.8 | 4.8 | 10.5 | 5.2 |
| Liver diseases | 5.2 | 3.4 | 1.6 | 0.8 | 2.1 |
| Peptic ulcer | 1.4 | 1.4 | 1.5 | 1.6 | 1.5 |
| Rheumatologic diseases | 2.1 | 2.0 | 2.3 | 1.3 | 1.9 |
Notes: Severity score was defined by none, one, or both of the following criteria: a 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: CKD, chronic kidney disease; ICD-9-CM, International Classification of Diseases, 9th Revision, Clinical Modification.