Crude and adjusted HR of a subsequent exacerbation and of mortality, as a function of the time after each successive exacerbation, estimated by Cox proportional hazards model
| Exacerbation sequence number | Exacerbation | Mortality | ||
| Crude HR | Adjusted* HR (95% CI) | Crude HR | Adjusted* HR (95% CI) | |
| First (reference) | 1.00 | 1.00 (reference) | 1.00 | 1.00 (reference) |
| Second | 1.78 | 1.76 (1.73 to 1.80) | 1.20 | 1.17 (1.14 to 1.20) |
| Third | 2.36 | 2.32 (2.27 to 2.37) | 1.31 | 1.26 (1.22 to 1.30) |
| Fourth | 2.86 | 2.79 (2.72 to 2.86) | 1.38 | 1.33 (1.28 to 1.38) |
| Fifth | 3.32 | 3.22 (3.13 to 3.32) | 1.37 | 1.33 (1.27 to 1.39) |
| Sixth | 3.71 | 3.60 (3.48 to 3.71) | 1.33 | 1.28 (1.21 to 1.36) |
| Seventh | 3.97 | 3.85 (3.71 to 3.99) | 1.38 | 1.34 (1.25 to 1.43) |
| Eighth | 4.42 | 4.23 (4.06 to 4.41) | 1.48 | 1.45 (1.34 to 1.57) |
| Ninth | 4.60 | 4.41 (4.20 to 4.62) | 1.45 | 1.44 (1.31 to 1.58) |
| Tenth or greater | 5.47 | 5.21 (5.07 to 5.36) | 1.49 | 1.50 (1.42 to 1.58) |
↵* Adjusted for age, sex, calendar time (cohort entry prior to 2000), and the modified Chronic Disease Score divided in quartiles with a fifth category to account for subjects with no or partial medication information in the year prior to cohort entry.