Dreijer et al reported a model for predicting an elevated INR ina hospitalized patient receiving a vitamin K antagonist. The authors are from Erasmus University and Reinier de Graaf Hospital in The Netherlands.
Patient selection: hospitalized patient receiving a vitamin K antagonist
Outcome: INR >= 4.5
Parameters:
(1) age in years
(2) sex
(3) serum ALT in U/L
(4) serum LDH in U/L
(5) serum albumin in g/L
(6) eGFR in mL per min per 1.73 square meter
(7) CRP in mg/L
(8) therapy with miconazole
(9) therapy with cotrimoxazole
(10) therapy with fluconazole
(11) therapy with voriconazole
(12) therapy with amiodarone
(13) therapy with antithyroid drugs
|
Parameter
|
Finding
|
Points
|
|
age
|
<= 60 years
|
0
|
|
|
> 60 years
|
0.016 * ((age) - 60)
|
|
sex
|
male
|
0
|
|
|
female
|
0.176
|
|
serum ALT
|
|
-0.003 * LN(ALT)
|
|
serum LDH
|
|
0.58 * LN(LDH)
|
|
serum albumin
|
|
-0.042 * (albumin)
|
|
eGFR
|
|
-0.009 * (eGFR)
|
|
CRP
|
|
0.206 * LN(CRP)
|
|
miconazole
|
no
|
0
|
|
|
yes
|
0.617
|
|
cotrimoxazole
|
no
|
0
|
|
|
yes
|
0.789
|
|
fluconazole
|
no
|
0
|
|
|
yes
|
0.987
|
|
voriconazole
|
no
|
0
|
|
|
yes
|
2.237
|
|
amiodarone
|
no
|
0
|
|
|
yes
|
0.826
|
|
antithyroid drugs
|
no
|
0
|
|
|
yes
|
0.587
|
X =
= SUM(points for all 13 parameters) - 4.282
probability of elevated INR =
= 1 / (1 + EXP((-1) * X))
Performance:
• The area under the ROC curve is 0.72.
