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Table 4 Summary of primary outcome results (Time to stable INR, supra = therapeutic INR, sub-terapeutic INRs, vitamin K given, and serious adverse events)

From: Optimal loading dose for the initiation of warfarin: a systematic review

   Proportion in INR range        
Study Dosing Day 3
(95% CI)
Day 5
95% (CI)
Mean time to time in range
Days (SD)
INR ≥4 unless otherwise stated
%
Vit K
Given
N (%)
Serious
Adverse
Events
N (%)
Other primary endpoints
5 mg v 10 mg          
   Harrison 5 mg 42% 67%δ - - 1(4%) 0    
  10 mg 36% 80%δ - - 4(16%) 0    
Crowther 5 mg 50% (26 to 75) 88%(75 to 102) - - 1(3%) - INR 2.0-3.0 for 2 consecutive days & not >3.0; p < .003
  10 mg 33% (-2 to 68) 69% (39 to 99) - - 0 - 10 mg (24%) v 5 mg (66%)
RR 2.22 (95% CI 1.3-3.7)
  
Kovacs 5 mg 3%* 46%
(36 to 57)**
P<.001
5.6 (1.4) INR ≥5
11%
- 2 (2%)    
  10 mg 25%* 83%
(74 to 89)**
  4.2 (1.1) 9% - 4 (4%)   
   Quiroz 5 mg - 52%** Median 5 INR >5
0%
- 0    
  10 mg - 56%** Median 5 0% - 1 (4%)    
   *taken from the published graph
δincludes discharged with INR in-range from (Ann Int Med Vol 127, 4, pg 133)
** in-range by day 5
5 mg vs. other doses          
   Ageno 5 mg - - 2.0 (1.0) P < .0001 - 3 (3%) 0 INR > 2.6
5 mg (42%)
p < .05
  2.5 mg - - 2.7 (1.2) P < .0001 - 5 (6%) 0 2.5 mg (26%) p < .05
   Shine Std (5 mg) - 63% δ 5 (0.9) ψ P = .007 "high" INR 2% - 1 (2%)    
  Calc - 77% δ 4.2 (0.9)ψ P = .007 INR >4.4 5% - 1 (2%)    
   δINR within range on or before day 6
ψ completers only
Age trials            
   Roberts Age adjusted   47%* 3.7 (1.3) Φ 6% - 0 Φ INR 2.0 - 3.0 for 2 consecutive days   
  Fennerty   25%* 4.3 (1.2) Φ 32% - 0 Φ Age v Fennerty;   p = 0.003
      INR >4.5    Mean days in range (SD)  
   Gedge Age
65-75 yrs
- - 4.6 (1.6) P = .03 3% P < .05 0 0 Age 3.0 (1.3) p = 0.03
  New Fennerty 65-75 yrs - - 3.8 (0.8) P = .03 20% P < .05 ^ 0 New Fennerty 2.7 (1.3) p = 0.03
      INR >4.5    Mean days in range (SD)  
  Age
>75 yrs
- - 4.5 (1.4) P = .003 3% P < .01 0 0 Age 2.9 (1.1) p = 0.04
  New Fennerty
>75 yrs
- - 3.5 (0.7) P = .003 37% P < .01 ^ 0 New Fennerty 2.4 (1.3) p = 0.04
   *taken from the published graph
Φ author correspondence
^ 1 (age not stated)
Genotyping            
   Hillman Model - - - 33% 0 2 (10%) % time INR in range
5 mg 42%
 
  5 mg - - - 30% 2 (doses) 5 (28%) Model 42%  
   Anderson Model - 70% - 30% - 4 (4%) average % of INR outside range
10 mg 33%
 
  10 mg - 68% - 37% - 5 (5%) Model 31%  
          % time INR in range  
   Caraco Model 1% * 49% * 4.8 (1.5) P < .001 - 0 0 5 mg 25% P < 0.001
  STD 5 mg 1% * 11% * 7.5 (3.1) P < .001 - 1 (1%) 1 (1%) Model 45% P < 0.001
  *taken from the published graph