Variable OR (95% CI) Χ2 p-value Age 1.005 (0.934 - 1.080) 0.016 0.9 Gender (M) 0.640 (0.168 - 2.436) 0.428 0.513 Vascular co-morbidity (Y) 0.750 (0.170 - 3.309) 0.144 0.704 BMI 0.974 (0.842 - 1.125) 0.132 0.717 Long vs. short course RT 0.535 (0.145 - 1.970) 0.886 0.346 ASA grade > 2 0.525 (0.097 - 2.837) 0.56 0.454 Pre-op Hb 1.000 (0.972 - 1.030) 0.001 0.993 Pre-op WCC 0.593 (0.352 - 0.999) 3.853 0.049 Pre-op neutrophils 0.557 (0.297 - 1.044) 3.333 0.068 Pre-op lymphocytes 0.723 (0.228 - 2.294) 0.304 0.582 Pre-op platelets 0.984 (0.970 - 0.998) 4.914 0.027 Pre-op serum creatinine 0.993 (0.956 - 1.031) 0.129 0.719

Table 3: Univariate logistic regression - preoperative factors associated with leak (n=48). RT=Radiotherapy, Hb=Haemoglobin, WCC=White Cell Count. *Continuous independent variables were analysed on a continuous basis for the purposes of univariate logistic regression. The odds ratio (OR) in this situation reflects the proportional increased risk (OR>1) or reduced risk (OR<1) of leak associated with each incremental unit increase in the independent variable in question.