Table 4

Univariate and multivariate Cox proportional hazards results for risk of death in 222 dogs with idiopathic IMHA for variables determined at time of first diagnosis with P < 0.20 and the variable "treatment protocol"

Univariate analysis


Variablea

Hazard ratio

Nb

95% CI

Pc


Icterus

2.47

222

1.52 - 4

0.0003*

Urea (20 mmol/L)

2.22

168

1.55-3.19

0.0004*

Creatinine d (50 μmol/L)

1.28

160

1.15-1.42

0.0012*

Red cell osmotic fragility

0.426

181

0.221 - 0.819

0.018*

Thrombocytes (50 ×109/L)

0.902

205

0.821-0.991

0.0184*

Age (years)

1.09

221

1.01-1.17

0.0266*

APTTe (seconds)

1.03

135

1-1.05

0.0445*

Spherocytes

0.663

215

0.396 - 1.11

0.115

Hematocrit (L/L)

0.0173

222

0.00011 - 2.77

0.109

Treatment protocol

1.12

222

0.679-1.86

0.65

Multivariate analysis


Urea (20 mmol/L)

2.56

164

1.729-3.789

0.0001*

Icterus

2.94

164

1.60 - 5.42

0.0005*

Spherocytes

0.38

164

0.2 - 0.72

0.0023*


a Variables were entered in the Cox proportional hazards model either as a factor or as a continuous variable, in which case the hazard ratio was calculated for the interval that is given in the table.

b Number of dogs is given in which the parameter was determined for which the Cox proportional hazards model calculated the hazard ratio.

c P = P value

d Plasma creatinine concentrations were corrected for body weight (van den Brom and Biewenga, 1981).

e APPT = Activated partial thromboplastin time

Piek et al. BMC Veterinary Research 2011 7:15   doi:10.1186/1746-6148-7-15

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