The Obesity Paradox in Colorectal Cancer Surgery: An Analysis of Korean Healthcare Big Data, 2012-2013.

Although it is well known that obesity increases the risk of colorectal cancer, several studies have recently suggested that those who are overweight or class-one obese have better outcomes after surgery. However, the impact of obesity on the success of colorectal cancer surgery remains controversial. The medical records of patients diagnosed with colorectal cancer who were treated surgically from 2012 through 2013 were retrospectively analyzed. Data from a total of 36,740 patients were provided by the Healthcare Big Data Hub of the Korean Health Insurance Review & Assessment Service. Multivariate analyses suggested that hospital length of stay (LOS) was significantly associated with age, cancer stage, and body mass index. The odds ratios of spending more than 2 weeks in the hospital for the overweight or class-one obese groups compared to the normal weight group were 0.903 (95% confidence interval, 0.866-0.941) and 0.887 (95% confidence interval, 0.851-0.924), respectively, while that of the underweight group was 1.280 (95% confidence interval, 1.202-1.362). The "obesity paradox" applies to colorectal cancer, as indicated by decreased hospital LOS of overweight and obese patients. This result suggests that there is a protective effect of nutritional status in obese patients, which contributes to recovery from colorectal cancer surgery.