Table 2.

—[Section 2.1] Warfarin 10 mg Loading Dose Nomogram Compared With Warfarin 5 mg Loading Dose Nomogram for Warfarin Initiation^7,8,10,11

Outcomes	No. of Participants (Studies), Follow-up	Quality of the Evidence (GRADE)	Relative Effect (95% CI)	Anticipated Absolute Effects
				Risk With Warfarin 5 mg Loading Dose Nomogram	Risk Difference With Warfarin 10 mg Loading Dose Nomogram (95% CI)
Bleeding events	420 (3 studiesa-c), 5-90 dd	Very lowe-g due to indirectness, imprecision	OR 1.90 (0.17-21.1)	5 per 1,000	0 more per 1,000 (from 10 fewer to 20 more)h
Recurrent VTE	420 (3 studiesa-c)	Very lowe-g due to indirectness, imprecision	Not estimable	0 per 1,000	10 more per 1,000 (from 30 more to 0 more)i

GRADE = Grades of Recommendations, Assessment, Development, and Evaluation. See Table 1 legend for expansion of other abbreviation.

^aAll pooled studies included only patients with acute VTE. Studies from which data could be pooled are Kovacs et al,⁹ Quiroz et al,¹⁰ and Schulman et al.¹¹

^bMinimal loss to follow-up; adherence to intention-to-treat principle in two of three studies; follow-up period short but adequate for this outcome; any lack of blinding should not impact objective outcome (laboratory value, INR); adequate allocation concealment; sample size calculations reported for two of three studies.

^cResults based on only three studies; one study shows no difference; one shows statistically significant reduction in time to therapeutic INR; and one had two parts to it, where one showed statistically significant reduction and the other did not.

^dMean follow-up period of 5 d for patients in the loading dose warfarin group from Schulman et al¹¹ (this was the shortest period, only mean is available).

^eData collectors unblinded.

^fIndirect given application aimed at outpatients with VTE; follow-up period is very short in two of three studies (5 d-2 wk).

^gNo studies were powered to detect differences in bleeding events between groups. Number of events is too sparse to draw any conclusions.

^hVery small number of events; risk difference calculated.

ⁱOR not estimable; absolute risk difference calculated.