Table 4.

Strength of the instrument in subgroups defined by observed risk factors

Variable	Instrument Strength	95% CI
U*	E[X|U* = 1, Z = 1] − E[X|U* = 1, Z = 0]
Patient Characteristics
Full Population	22.8%	21.8 – 23.8%
Female Gender	22.1%	23.6 – 28.8%
Age ≥ 75	23.1%	21.9 – 24.2%
History of GI Bleed	18.2%	10.3 – 26.2%
History of Peptic Ulcer Disease	18.9%	13.5 – 24.3%
History of Coronary Procedure or Hospitalization	22.6%	20.0 – 20.5%
Recent/Concomitant Medications
Concomitant Use of a GI Protective Drugs	18.7%	14.1 – 23.2%
History of GI Protective Drug Use	20.1%	18.1 – 22.0%
Recent Use of Glucocorticoids	19.7%	16.2 – 23.2%
Recent Use of Warfarin	14.9%	12.1 – 17.7%