Adjusted hazard ratio (HR) of a subsequent exacerbation and of death associated with age, sex, calendar time of cohort entry and quartiles of the modified Chronic Disease Score by Cox proportional hazards model with time-dependent covariate defining the exacerbation number
| Exacerbation | Death | |
| HR (95% CI) | HR (95% CI) | |
| Age (per 10 years) | 0.90 (0.89 to 0.91) | 1.66 (1.64 to 1.68) |
| Men | 1.21 (1.19 to 1.22) | 1.37 (1.35 to 1.40) |
| Cohort entry after year 2000 | 0.82 (0.80 to 0.83) | 0.90 (0.88 to 0.92) |
| Modified Chronic Disease Score | ||
| First quartile | 1.00 (reference) | 1.00 (reference) |
| Second quartile | 1.08 (1.06 to 1.10) | 1.03 (1.00 to 1.06) |
| Third quartile | 1.10 (1.08 to 1.12) | 1.15 (1.12 to 1.18) |
| Fourth quartile | 1.08 (1.06 to 1.10) | 1.41 (1.37 to 1.45) |