Study group populations for the STRIDE dataset, including 5:1 propensity matching.

There are 93,149 patients with gastroesophageal reflux disease (GERD), of which 70,477 are at least 18 years old. In all study groups other than the one in which clopidogrel patients are excluded, the populations are matched (and balanced) based on clopidogrel use and other covariates such as age, gender, race, length of observation, number of unique drugs mentioned in the record, and validated proxies of health status (based on the number of unique disease concepts attributed to each patient). The matching process attempts to achieve a ratio of 1:5 (exposure to control), but will settle for 1:3 or 1:1 if there are not enough controls from which to draw.* balanced for clopidogrel use† patients on clopidogrel are excluded‡ patients are restricted by ageStudy group populations for the STRIDE dataset, including 5:1 propensity matching.