Table 9 Poisson regression analysis of secondary outcomes among patients receiving warfarin therapy
| Â | Bleeding episodes | Thromboembolic events | Emergency department visit | Hospitalization | ||||
|---|---|---|---|---|---|---|---|---|
Variable | IRR (95%CI) | p-value | IRR (95%CI) | p-value | IRR (95%CI) | p-value | IRR (95%CI) | p-value |
Patient group | ||||||||
 UMC | 1.45(0.79,2.65) | 0.22 | 0.84(0.26,2.68) | 0.77 | 7.59(2.68,21.50) |  < 0.001* | 1.75(0.79,3.87) | 0.17 |
 PLAC | 1.00 |  | 1.00 |  | 1.00 |  | 1.00 |  |
Sex | ||||||||
 Female | 0.90(0.53,1.53) | 0.69 | 0.55(0.21,1.45) | 0.23 | 1.50(0.79,2.84) | 0.21 | 0.82(0.43,1.57) | 0.55 |
 Male | 1.00 |  | 1.00 |  | 1.00 |  | 1.00 |  |
Age | ||||||||
 18–30 | 0.74(0.26,2.16) | 0.58 | 0.85(0.13,5.53) | 0.86 | 2.02(0.72,5.69) | 0.19 | 1.31(0.39,4.39) | 0.67 |
 31–45 | 1.12(0.43,2.91) | 0.82 | 1.07(0.21,5.46) | 0.94 | 0.84(0.31,2.28) | 0.73 | 1.00(0.33,3.02) | 1.00 |
 46–64 | 0.78(0.31,1.95) | 0.59 | 0.69(0.13,3.66) | 0.66 | 0.61(0.22,1.67) | 0.34 | 0.51(0.17,1.56) | 0.24 |
  ≥ 65 | 1.00 |  | 1.00 |  | 1.00 |  | 1.00 |  |
Residence | ||||||||
 Addis Ababa | 1.04(0.59,1.84) | 0.89 | 1.25(0.41,3.84) | 0.69 | 1.16(0.65,2.07) | 0.62 | 1.57(0.77,3.17) | 0.21 |
 Out of Addis Ababa | 1.00 |  | 1.00 |  | 1.00 |  | 1.00 |  |
Presence of comorbidities | ||||||||
 No | 1.65(0.56,4.87) | 0.37 | 1.73(0.26,11.31) | 0.57 | 0.69(0.22,2.25) | 0.55 | 0.75(0.18,3.04) | 0.68 |
 Yes | 1.00 |  | 1.00 |  | 1.00 |  | 1.00 |  |
CHA2DS2-VASc Risk | ||||||||
 High risk | 1.87(0.78,4.52) | 0.16 | 15.13(1.47,155.52) | 0.02* | 1.79(0.80,4.03) | 0.15 | 2.22(0.80,6.14) | 0.13 |
 Low risk | 1.59(0.67,3.77) | 0.29 | 4.09(0.44,38.07) | 0.22 | 0.38(0.14,1.08) | 0.06 | 1.11(0.37,3.32) | 0.85 |
 Moderate risk | 1.00 |  | 1.00 |  | 1.00 |  | 1.00 |  |
HAS-BLED risk | ||||||||
 High risk | 0.81(0.27,2.39) | 0.70 | 0.14(0.01,1.93) | 0.14 | 0.44(0.14,1.44) | 0.18 | 0.63(0.17,2.24) | 0.47 |
 Low risk | 0.69(0.27,1.77) | 0.44 | 1.56(0.29,8.08) | 0.59 | 2.27(0.79,6.53) | 0.13 | 1.09(0.35,3.41) | 0.88 |
 Moderate risk | 1.00 |  | 1.00 |  | 1.0 |  | 1.00 |  |
Target INR range | ||||||||
 2–3 | 0.87(0.42,1.78) | 0.69 | 0.86(0.25,3.01) | 0.81 | 1.06(0.41,2.79) | 0.90 | 0.87(0.35,2.17) | 0.76 |
 2.5–3.5 | 1.00 |  | 1.00 |  | 1.00 |  | 1.00 |  |
Presence of warfarin drug interaction | ||||||||
 No | 0.99(0.57,1.72) | 0.97 | 0.69(0.24,2.04) | 0.51 | 0.90(0.49,1.62) | 0.73 | 0.92(0.45,1.86) | 0.81 |
 Yes | 1.00 |  | 1.00 |  | 1.00 |  | 1.00 |  |
Time in the therapeutic range | ||||||||
  < 65% | 0.86(0.39,1.88) | 0.71 | 0.35(0.08,1.53) | 0.16 | 0.31(0.13,0.73) | 0.007* | 0.27(0.10,0.70) | 0.007* |
  ≥ 65 | 1.00 |  | 1.00 |  | 1.0 |  | 1.00 |  |
Comorbidity score | ||||||||
 No | 0.22(0.05,0.97) | 0.05 | 0.38(0.02,6.33) | 0.49 | 0.54(0.12,2.38) | 0.41 | 0.33(0.05,2.11) | 0.24 |
 Mild | 0.43(0.16,1.17) | 0.09 | 0.81(0.12,5.58) | 0.83 | 0.99(0.37,2.71) | 0.99 | 0.70(0.21,2.38) | 0.57 |
 Moderate | 0.63(0.24,1.63) | 0.34 | 0.31(0.04,2.53) | 0.28 | 0.93(0.35,2.45) | 0.88 | 1.18(0.36,3.85) | 0.78 |
 Severe | 1.00 |  | 1.00 |  |  |  |  |  |
 \ INR monitoring interval | 0.97(0.96,0.99) |  < 0.001* | 0.98(0.96,1.01) | 0.17 | 0.97(0.95,0.99) |  < 0.001* | 0.98(0.97,1.00) | 0.06 |
Percentage of days in different INR ranges | ||||||||
 Time below range | 1.02(0.99,1.04) | 0.07 | 0.99(0.93,1.07) | 0.99 | 0.99(0.90,1.01) | 0.83 | 0.99(0.95,1.03) | 0.55 |
 Time therapeutic range | 1.01(0.99,1.04) | 0.33 | 0.98(0.91,1.05) | 0.53 | 0.97(0.88,1.06) | 0.48 | 0.97(0.93,1.02) | 0.19 |
 Time above range | 1.01(0.99,1.02) | 0.38 | 0.99(0.92,1.06) | 0.75 | 0.99(0.90,1.09) | 0.83 | 1.00(0.97,1.04) | 0.88 |
 Average weekly warfarin dose | 0.99(0.98,1.01) | 0.93 | 0.99(0.96,1.02) | 0.54 | 0.99(0.98,1.01) | 0.71 | 0.99(0.98,1.02) | 0.82 |