Age-specific impact of comorbidity on postoperative outcomes in older patients with colorectal cancer.

ABSTRACT

INTRODUCTION: Age and comorbidity are considered the strongest predictors for adverse events after colorectal cancer (CRC) surgery. We aimed to study the interaction of age and comorbidity and to gain better insight in options to improve care for the growing group of older patients. MATERIALS AND METHODS: We included all patients ≥70 years undergoing elective surgery for non-metastatic CRC between 2011 and 2019 in the Netherlands. Baseline characteristics, surgical and non-surgical complications, readmission, and short-term mortality were collected from the Dutch Colorectal Audit (DCRA). The cohort was stratified by 70-79, 80-89, and ≥ 90 years. Comorbidity prevalence and postoperative outcomes were determined per age group. We analyzed the interaction (age-group*comorbidity) with all outcomes using multivariate logistic regression analysis. Age-stratified analysis was indicated if the interaction was significant. RESULTS: We included 25,727 patients of 70-79 years, 12,198 patients of 80-89 years, and 713 of ≥90 years. Non-surgical complications and mortality increased with older age, while surgical complications significantly decreased. However, the association of a Charlson Comorbidity Index (CCI) score ≥ 3, cardiovascular, and cardiopulmonary disease with adverse postoperative outcome decreased with older age. For example, the odds ratio (OR) of a CCI score ≥ 3 for non-surgical complications was 1.79 (confidence interval [CI] 95% 1.66-1.94), 1.50 (CI 95% 1.36-1.65), and 1.21 (CI 95% 0.80-1.81) for, respectively, 70-79, 80-89, and ≥ 90 years. DISCUSSION: The rate of non-surgical complications after CRC surgery increased with older age, although older age itself became less associated with comorbidity. Perhaps risk assessment in the oldest patients should shift towards other predictors, such as frailty.