Table 4.

Explanations for the 8 false positive strokes and 9 false negative strokes identified by administrative data

8 false positive perioperative strokes

4 patients were falsely coded as having a perioperative stroke

1 preoperative stroke was miscoded as being a postoperative stroke

3 strokes occurred after admission to the hospital for other reasons

One occurred after a laparoscopic cholecystectomy

One occurred after admission to the hospital for treatment of pneumonia

One occurred after admission to the hospital for lower extremity ischemia

9 false negative perioperative strokes

3 were post-discharge strokes

2 were misclassified as preoperative strokes

4 strokes were not coded at all in the discharge data