Body mass index affects postoperative daily activities of older patients after gastrectomy

Purpose: This study aimed to examine the impact of preoperative body mass index (BMI) on postoperative activities of daily living (ADL) and clinical outcomes in older patients who underwent curative gastrectomy.

Methods: This was a retrospective observational study using a nationwide inpatient database in Japan. The study included 1769 patients with gastric cancer, aged ≥ 65 years old, who underwent gastrectomy. BMI was defined as per the World Health Organization classifications for Asian populations. Primary outcome was ADL at discharge, assessed by Barthel index. Secondary outcomes included postoperative complications and length of hospital stay.

Results: Patients analyzed included 890 (50.3%) aged 65-74 years, 745 (42.1%) aged 75-84 years, and 134 (7.6%) aged ≥ 85 years; 71.5% were male. According to BMI classification, 11.9% patients were considered underweight (< 18.5 kg/m²), 46.7% were in the standard range (18.5 to < 23 kg/m²), 34.1% were classified as overweight (23-27.5 kg/m²), and 7.3% were in the obese group (≥ 27.5 kg/m²). In multivariate analysis, a significant association was observed between BMI and Barthel index scores (underweight group: standardized coefficient, - 0.040; compared with standard group; p = 0.013), postoperative complication (obese group: odds ratio, 1.562; compared with standard group; p = 0.034), and length of hospital stay (obese group: standardized coefficient, 0.047; compared with standard group; p = 0.019).

Conclusion: Perioperative management with a focus on BMI is important in older patients undergoing elective curative gastrectomy.