Using highly variable warfarin dosing to identify patients at risk for adverse events

Thrombosis Journal

Table 4 Multivariate analysis of risk factors for extreme warfarin variability.

Chart Review Variables	Odds Ratio (95% CI)	p-value
Acetaminophen	4.0 (1.33 to 6.30)	0.01
Adherence	2.0 (0.87 to 4.65)	0.10
Alcohol	2.5 (0.65 to 10.00)	0.18
Alternative Medication	2.0 (0.38 to 9.63)	0.44
Amiodarone	*	*
Antibiotic Use	2.7 (1.11 to 6.33)	0.03
Cancer	*	*
CHF (Decompensated)	2.0 (0.34 to 11.58)	0.44
Decreased Oral Intake	12.2 (2.25 to 65.68)	0.004
Diarrhea	2.8 (0.51 to 15.67)	0.23
Dietary Supplement	1.0 (0.12 to 7.90)	0.98
Dietary Vitamin K	2.1 (0.86 to 4.92)	0.10
Hospitalizations/Nursing Home	21.3 (6.21 to 73.14)	< 0.001
Missed Appointments	1.6 (0.51 to 5.15)	0.42
Nausea/Vomiting	4.4 (0.70 to 27.91)	0.11
NSAID Use	1.3 (0.36 to 4.72)	0.69
Procedures	1.4 (0.59 to 3.36)	0.44
Systemic Steroids	6.1 (1.10 to 34.20)	0.04

Variables are adjusted for all other variables in the table, as well as for age, gender, race, and comorbid conditions (not shown).
* These variables were not estimable in the multivariate model, because too few control patients had these characteristics. Therefore, these variables were omitted from the model.

ISSN: 1477-9560