The Relationship Between BMI and Postoperative Complications Among Colorectal Cancer Patients Undergoing Surgery.

INTRODUCTION: Colorectal cancer (CRC) is common worldwide, and surgery is one of the main treatments. Postoperative complications are a concern. The primary objective of this study is to determine whether elevated body mass index (BMI), the presence of comorbidities, tumor characteristics, and the type of surgery are associated with an increased risk of postoperative complications such as wound infections, pulmonary complications, anastomotic leak, venous thromboembolism (VTE), bowel obstruction, and incisional hernia. The secondary objective is to describe the characteristics of colorectal cancer patients with different BMI groups.

METHODOLOGY: A retrospective cohort study was conducted using a non-probability sampling technique at a tertiary National Guard Hospital in Riyadh, Saudi Arabia. This study involved 122 patients aged 18 years or more who underwent elective or emergency surgery for colorectal cancer between the years 2015 and 2022. Data analysis was performed using Statistical Package for Social Sciences (SPSS) version 27 (IBM SPSS Statistics, Armonk, NY). Descriptive statistics (mean and standard deviation) were used for quantitative variables, while qualitative variables were presented as percentages and frequencies. Non-parametric tests were applied to compare qualitative variables. Quantitative variables were analyzed using the analysis of variance (ANOVA) test. Significance was established at a p-value of 0.05. Ethical considerations were followed throughout the study. Prior to conducting the study, ethical approval was obtained from the Institutional Review Board of King Abdullah International Medical Research Center (KAIMRC) (approval number: IRB/1598/23).

RESULTS: High BMI scores were observed in patients with postoperative complications. A statistically significant variation in BMI scores (p-value < 0.05) was found between patients with complications and without complications. This observation suggests that factors beyond excessive body weight might contribute to the onset of postoperative complications. Moreover, elevated BMI scores were more prevalent in males and were associated with reduced hemoglobin (Hgb) levels, underscoring the potential influence of physiological variables on the emergence of postoperative complications (p-value < 0.05). Tumors located in the rectum or rectosigmoid regions, as well as partial colectomy procedures, exhibited a higher risk of postoperative complications (p-value < 0.05). However, no significant connections were identified between the presence of comorbidities and the occurrence of postoperative complications (p-value > 0.05).

CONCLUSION: This study highlights the impact of BMI on postoperative outcomes in colorectal cancer patients. Higher BMI was associated with unfavorable postoperative outcomes, such as an increased risk of VTE and fluid collection. However, no significant differences in mortality rates or length of hospital stay (LOS) were observed across various BMI categories. Factors beyond BMI, including tumor characteristics, the type of surgical intervention, and preoperative care, play a significant role in determining postoperative outcomes. Therefore, it is essential to adopt a comprehensive approach that considers multiple factors when managing postoperative complications in colorectal cancer patients, particularly those with higher BMI.