Prognostic indicators in colic horses 113 Ta bl e 3 . Descriptive analyses of clinical and laboratory variables in medically and surgically treated colic cases demonstrating p-values < 0.15 in either Wilcoxon/Kruskall Wallis Rank Sum test for continuous variables or Fisher Exact test for nominal variables. Survivors Non-survivors Variables Medically treated colic cases: Heart rate /min Respiratory rate /min CRT sec Rectal temperature °C Abnormal mucous membrane PCV % HGB g/l1 Fibronogen g/l Alfa- globulin g/l Gamma- globulin g/l Lactate mmol/l Total Ca mmol/l Surgically treated colic cases: Heart rate /min Breath rate /min2 Temperature difference from 38 °C Abnormal mucous membrane No abdominal sounds2 CRT sec2 PCV %2 HGB g/l2 Beta-globulin g/l Gamma- globulin g/l Cl mmol/l K mmol/l Lactate mmol/l2 D-dimer > 1.5 mg/l D-dimer > 0.5 mg/l n 36 35 36 36 36 36 34 33 36 36 36 34 22 22 20 22 22 22 22 22 20 20 22 22 20 22 22 Median(range) or no/ (%) 48 (32-96) 20 (8-50) 2 (2-4) 37.9 (36.6-38.8) 16 (44%) 34 (22-50) 122 (82-181) 3 (2-7) 9 (6.9-14.3) 7.8 (4.2-14.7) 1.2 (0.5-11.1) 3.0 (1.5-3.4) 44 (36-80) 20 (12-40) 0.3 (0.0-1.0) 5 (23 %) 2 ( 9%) 3 (2-3) 38 (29-43) 138 (106-163) 10.5 (7.7-20.0) 8.7 (3.2 -12.1) 99 (89-108) 3.5 (2.3-4.5) 1.6 (0.8-7.1) 2 (9%) 7 (33%) n 10 10 9 10 10 10 10 9 9 9 9 9 24 24 24 24 24 24 24 24 23 23 24 24 24 24 24 Median (range) or no (%) 72 (32-120) 28 (15-34) 3 (2-6) 38.4 (37.9-39.6) 7 (70%) 48 (33-69) 180 (123-248) 3 (1-5) 7.7 (2.9-12.4) 5.8 (3.5-13.7) 3.7 (1.1-13.1) 2.7 (2.1-2.9) 79 (36-148) 30 (15-72) 0.6 (0.0-2.5) 19 (79%) 14 (58%) 4 (2-7) 42 (28-56) 153 (112-199) 12.2 (7.4-19.8) 7.6 (2.2-12.6) 95 (87-108) 3.8 (2.6-5.2)) 3.6 (1.1-13.0) 12 (50%) 17 (71%) 1 Excluded from further analysis due to high correlation to PCV. 2 Excluded from further analysis due to high correlation to heart rate. n = number of observations. The ﬁnal multivariable model was built using logistic regression in a forward selection proce- dure as described by Hosmer & Lemeshow (2000) using Intercooled Stata for Windows 7.0 (Stata Corporation, College Station, TX, USA). Model ﬁt was assessed using the overall Pear- son ﬁt, the Hosmer-Lemeshow test and the Re- ceiver Operating Characteristic (ROC) curve. Possible outliers were identiﬁed using the ∆ß and ∆ deviance test (Hosmer & Lemeshow 2000). The sensitivity and speciﬁcity for vari- ous probability cut-offs were graphically as- sessed. Linearity for continuous variables was also as- sessed comparing the continuous variable grouped into quartiles and with a graphical ap- Acta vet. scand. vol. 45 no. 1-2, 2004