Preoperative hypokalemia can increase complications after colorectal cancer surgery: a propensity score matching analysis

BACKGROUND: Whether hypokalemia can affect the short-term outcomes of CRC patients after radical surgery remains unclear. The purpose of this study was to investigate the impact of preoperative hypokalemia on the short-term outcomes for colorectal cancer (CRC) patients who underwent radical CRC surgery using propensity score matching (PSM). METHODS: We retrospectively enrolled consecutive CRC patients from Jan 2011 to Dec 2021 in a single-center hospital. Hypokalemia was defined as a serum potassium concentration < 3.5 mmol/L. The short-term outcomes were compared between the hypokalemia group and the normal blood potassium group. In addition, univariate and multivariate logistic regression analyses were conducted to identify independent risk factors for overall complications. RESULTS: A total of 6183 CRC patients who underwent radical surgery were included in this study, of whom 390 (6.3%) patients were diagnosed with hypokalemia before surgery. After 1:1 ratio PSM, there were 390 patients in the hypokalemia group and in the normal potassium group. No significant difference was found between the two groups after PSM in terms of baseline information (p > 0.05). Regarding short-term outcomes, the hypokalemia group had a longer hospital stay (p = 0.028), a higher proportion of overall complications (p = 0.048) and a higher incidence of postoperative pneumonia (p = 0.008) after PSM. Moreover, hypokalemia (p = 0.036, OR = 1.291, 95% CI = 1.017–1.639) was an independent risk factor for overall complications. CONCLUSION: Preoperative hypokalemia could increase complications after CRC surgery and prolong the hospital stay. Moreover, preoperative hypokalemia was an independent risk factor for overall complications.