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 



Variable^{a} 
Hazard ratio 
N^{b} 
95% CI 
P^{c} 


Icterus 
2.47 
222 
1.52  4 
0.0003* 
Urea (20 mmol/L) 
2.22 
168 
1.553.19 
0.0004* 
Creatinine ^{d }(50 μmol/L) 
1.28 
160 
1.151.42 
0.0012* 
Red cell osmotic fragility 
0.426 
181 
0.221  0.819 
0.018* 
Thrombocytes (50 ×10^{9}/L) 
0.902 
205 
0.8210.991 
0.0184* 
Age (years) 
1.09 
221 
1.011.17 
0.0266* 
APTT^{e }(seconds) 
1.03 
135 
11.05 
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 
0.6791.86 
0.65 
Multivariate analysis 



Urea (20 mmol/L) 
2.56 
164 
1.7293.789 
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:10.1186/17466148715 