Table 4. Temporal Trends of Stroke After Transient Ischemic Attack.
| Time horizon for stroke risk | Total No. of events | Epoch 1 (1948-1985) | Epoch 2 (1986-1999) | Epoch 3 (2000-2017) | P value for trend |
|---|---|---|---|---|---|
| 90 d | |||||
| No. of events, No./total | 51/435 | 26/155 | 18/162 | 7/118 | |
| Proportion of cases with subsequent stroke, % | 11.7 | 16.7 | 11.1 | 5.9 | |
| Hazard ratio (95% CI)a,b | 1 [Reference] | 0.60 (0.33-1.12) | 0.32 (0.14-0.75) | .005 | |
| 1 y | |||||
| No. of events, No./total | 67/435 | 37/155 | 21/162 | 9/118 | |
| Proportion of cases with subsequent stroke, % | 15.4 | 23.9 | 12.9 | 7.6 | |
| Hazard ratio (95% CI)a,b | 1 [Reference] | 0.49 (0.28-0.84) | 0.29 (0.14-0.60) | <.001 | |
| 5 y | |||||
| No. of events, No./total | 107/435 | 55/155 | 33/162 | 19/118 | |
| Proportion of cases with subsequent stroke, % | 24.6 | 35.5 | 20.4 | 16.1 | |
| Hazard ratio (95% CI)a,b | 1 [Reference] | 0.48 (0.31-0.74) | 0.37 (0.22-0.63) | <.001 | |
| 10 y | |||||
| No. of events, No./total | 130/435 | 64/155 | 42/162 | 24/118 | |
| Proportion of cases with subsequent stroke, % | 29.9 | 41.3 | 25.9 | 20.3 | |
| Duration of follow up, median (range)c | 6.49 (0.74-10) | 6.85 (1.88-10) | 5.39 (2.19-8.62) | ||
| Hazard ratio (95% CI)a,b | 1 [Reference] | 0.52 (0.35-0.78) | 0.43 (0.27-0.69) | <.001 |
a
Each row represents a separate Cox regression analysis with a different time horizon; hence, the number at risk (n = 435) is the same in all analyses.
b
Age- and sex-adjusted.
c
Only median duration of follow-up for the 10-year time horizon is reported. In all other time strata (90 days, 1 year, 5 years), all participants have complete follow-up and the median follow-up time coincides with the maximum duration of these time windows.