Relationship between pre-operative glycated haemoglobin and surgical site infection in patients undergoing elective colon cancer surgery

Abstract

Surgical site infections remain a significant cause of morbidity following colon cancer surgery. Although diabetes has been recognised as a risk factor, patients with asymptomatic diabetes are likely underdiagnosed. The aim of the present study was to determine the relationship between preoperative glycated haemoglobin (HbA1C), clinicopathological characteristics and the influence on surgical site infection in a cohort of patients undergoing potentially curative colon cancer surgery. Patients who underwent elective, potentially curative colon cancer surgery between January 2011 and December 2014 were assessed for HbA1C levels (mmol/mol) measured within 3 months preoperatively. Clinicopathological data were recorded in a maintained database. A multivariate binary logistic regression model was used to assess the relationship between HbA1C, clinicopathological characteristics and surgical site infections. A total of 362 patients had HbA1C levels preoperatively recorded. HbA1C was significantly associated with body mass index (BMI), diabetes, smoking status, visceral fat area and skeletal muscle index. As determined by multivariate analysis, preoperative HbA1C levels remained independently associated with an increased risk of surgical site infections (OR 1.69, 95% CI 1.05-2.7; P=0.031) together with BMI (OR 1.91, 95% CI 1.36-2.67; P<0.001). Notably, in the present study, tumour-based factors, such as tumour location and TNM status, were not associated with infective complications. By contrast, host factors, such as BMI and pre-operative HbA1C were associated with surgical site infections suggesting that these factors were of more importance in determining short-term outcomes. In conclusion, objective measurements of BMI and HbA1C effectively stratified the risk of developing surgical site infection from 8 to 59%; therefore, HbA1C levels should be determined to allow for preoperative optimisation.

Keywords: cancer; colon; pre-operative glycated haemoglobin; surgery; surgical site infection.

Figure 1.

Preoperative HbA1c recorded for patients undergoing elective curative colon cancer surgery. The medical records for patients who underwent elective curative resection for TNM Stage I–III colon cancer in the West of Scotland from January 2011-2014 were examined to determine the presence of preoperative HbA1C levels. The proportion of diabetic and non-diabetic patients with preoperative HbA1C levels available are shown in the flow diagram. HbA1C, glycated haemoglobin.

Figure 2.

Scatter plot of body mass index vs. preoperative HbA1C level (mmol/mol). The blue dots represent males and green dots represent females with corresponding best fit line for both sexes. Pearson's correlation analysis performed using SPSS Statistics software showed r=−0.24 (P=0.751) for males and r=−0.32 (P=0.736) for females. HbA1C, glycated haemoglobin.

Figure 3.

Relationship between pre-operative HbA1C (mmol/mol), BMI and surgical site infection. The green line shows the rate of surgical site infection for patients with preoperative HbA1C <42 with corresponding BMI. The blue line shows the rate of surgical site infection for patients with preoperative HbA1C 42-28 with corresponding BMI. The yellow line shows the rate of surgical site infection for patients with preoperative HbA1C >48 with corresponding BMI. BMI, body mass index; HbA1C, glycated haemoglobin.