The association between early postoperative food intake and postoperative hospital length of stay in patients undergoing cardiac surgery: A retrospective observational single-center study

Background & Aims

Perioperative nutritional status is critical during the postoperative recovery process in patients undergoing cardiac surgery. Several studies on patients undergoing cardiac surgery have reported low energy intake in early postoperative food intake via oral nutrition; however, no study has shown an association of low energy intake with postoperative hospital length of stay (LOS). This study aimed to determine whether early postoperative low food intake was associated with prolonged postoperative hospital LOS in patients undergoing cardiac surgery.

Methods

This was a retrospective, observational, singlecenter study conducted in patients aged ≥18 years undergoing elective cardiac surgery from January 1, 2020, to May 31, 2023. Patients were categorized by food intake as food intake < 50% (low food intake group) and ≥ 50% (adequate food intake group) at lunch on postoperative day (POD) 3. The primary outcome of this study was the postoperative hospital LOS. A generalized linear model was used to examine the association between food intake and postoperative hospital LOS using the following explanatory variables: age, European System for Cardiac Operative Risk Evaluation (EuroSCORE) II value, preoperative risk of malnutrition, activities of daily living status, Sequential Organ Failure Assessment score, and C-reactive protein level.

Results

Of the 315 patients, 104 (33.0%) had a food intake of <50% on POD3. There were no significant differences in age, sex, EuroSCORE II value, and comorbidities between the two groups. Patients in the low-food intake group had a significantly lower Barthel Index (6.7% vs. 1.4%, p = 0.017) and a higher malnutrition risk according to the Mini Nutritional Assessment Short Form score (40.4% vs. 28.2%, p = 0.043). Food intake of <50% on POD3 was associated with prolonged postoperative hospital LOS (β = 1.135 [95% confidence interval: 1.004–1.262], p = 0.018).

Conclusions

Low food intake on POD3 is associated with prolonged postoperative hospital LOS in patients undergoing elective cardiac surgery. Early postoperative food intake should be closely monitored in patients after elective cardiac surgery.