Table 10.

—[Section 4.1.2] Optimal Therapeutic INR Range: Lower Target vs 2 to 3¹¹⁹

Outcomes	No. of Participants (Studies)	Quality of the Evidence (GRADE)	Relative Effect (95% CI)	Anticipated Absolute Effects
				Risk With INR 2-3	Risk Difference With INR < 2 (95% CI)
Major hemorrhage per 100 patient-y, various definitions	78,493 (17 studiesa)	Very lowa,b due to risk of bias, inconsistency	RR 1.1 (0.7-1.7)	Study population
				6 per 1,000	1 more per 1,000 (from 2 fewer to 4 more)
				Moderate
				23 per 1,000	2 more per 1,000 (from 7 fewer to 16 more)
Thromboembolism per 100 patient-y	827 (4 studiesc)	Moderated-f due to risk of bias, large effect, dose-response gradient	RR 3.5 (2.8-4.4)	Study population
				46 per 1,000	115 more per 1,000 (from 83 more to 157 more)
				Moderate
				40 per 1,000	100 more per 1,000 (from 72 more to 136 more)

See Table 1-3 legends for expansion of abbreviations.

^aEight of the studies were retrospective cohorts.

^bFour studies showed higher risk of bleeding, with INR < 2.

^cOnly one study had a randomized control design.

^dNo explanation was provided.

^eAt least 2.8 times more frequent thromboembolism.

^fIt is biologically plausible with more thromboembolism at a lower INR.