Table 2.

Rates, cumulative risks from beginning of period to day 21,* and rate ratios of secondary ischemia and recurrent hemorrhage

Days after SAHSecondary ischemiaRecurrent hemorrhage
Patient days at riskEventsEvent rate per 100 patient daysRate ratio (95% CI)Cumulative risk, %Patient days at riskEventsEvent rate per 100 patient daysRate ratio (95% CI)Cumulative risk, %
For the analysis on rates of secondary ischemia, patients were censored when they died. For the analysis on rates of rebleeding, patients were censored not only when they died, but also when the aneurysm was treated. Therefore, the number of patients at risk and thus the number of patient days for recurrent hemorrhage are smaller than for secondary ischemia.
* The interpretation of the cumulative risk is that on day 1 the risk of developing secondary ischemia for an individual patient, if he or she will survive until day 21, is 34.3%. At day 11 this risk has decreased to 9.2%.
† Relative to risk from day 4 to 10.
SAH = subarachnoid hemorrhage.
0338.500.00.034.3337.5278.05.2 (2.7–10.0)41.0
1 to 3855252.90.9 (0.5–1.4)34.3641162.51.6 (0.8–3.3)35.9
4 to 101530.5523.4128.2838.5131.6131.4
11 to 14734.5710.3 (0.1–0.6)9.231572.21.4 (0.6–3.6)23.3
15 to 211173100.90.3 (0.1–0.5)5.7298.582.71.7 (0.7–4.2)16.0