Figure 4. Exploratory analyses to improve accuracy of hemorrhagic stroke codes.

*Excluding other stroke code same day: excluded cases with a diagnostic code for >1 stroke pathologic type on the same day. This was done because a patient who has one pathologic stroke type (e.g., ischemic stroke) can sometimes develop a complication and subsequent brain scan appearances similar to another pathologic stroke type (e.g., a patient with ischemic stroke can have a bleed in the brain as a result of the ischemic stroke, which could lead to a false diagnosis of an intracerebral hemorrhage [ICH]). CI = confidence interval; PPV = positive predictive value; SAH = subarachnoid hemorrhage.