Fig. 2From: Healthcare exposures and associated risk of endocarditis after open-heart cardiac valve surgeryCase-crossover design with each patient acting as their own control. “At risk” period defined as a 1–90 days (3 months) after exposure (the standard definition), b 1–30 days (1 month) after exposure, c 1–180 days (6 months) after exposure, and d 90–180 days after exposureBack to article page