Preoperative low-energy diets for patients with...

Preoperative low-energy diets for patients with body mass index >30kg/m2 undergoing non-bariatric surgery: A pilot feasibility randomized clinical trial and a systematic review and meta-analysis of efficacy data

Abstract

Abstract Background The current evidence for preoperative low energy diets (LEDs) for patients with body mass index (BMI) > 30 kg/m2 prior to non-bariatric surgery rests on high-risk of bias studies. A randomized clinical trial (RCT) is warranted to bridge this knowledge gap. Prior to a larger RCT, we conducted a pilot feasibility RCT to address potential hurdles for the larger trial. Methods The pilot feasibility multicenter trial was conducted in Canada at four centers between January and October 2024. Patients were randomized (1:1 randomly permuted online blocked allocation) to receive a 3-week LED protocol or standard care. All patients older than 18 years of age with BMI body greater than 30kg/m2 undergoing elective non-bariatric intra-abdominal or orthopedic surgery were evaluated for enrollment. Main exclusion criteria were contraindications to LED and surgery scheduled without at least 3 weeks notice. The primary outcome was descriptive including the following feasibility outcomes: recruitment rate, randomization percentage, intervention adherence, and follow-up completion. Clinical outcomes included anthropometric data. The primary outcome analysis was descriptive. Additionally, a random effects meta-analysis was performed using previously published RCT data for 30-day postoperative morbidity. Last follow-up date was January 14th, 2025. Results There were 91 patients randomized (LED n=45, control n=46). Out of 373 eligible patients, 57% (95%CI 51.4-63.1%) were randomized. Out of these 91 randomized patients, 81 (89%, 95%CI 80.7-94.6%) had complete follow-up. LED adherence was 81.7% (95%CI 74.1-89.3%). Analysis of covariance suggested patients in the LED group lost more weight during the 3-week intervention period (MD 4.5kg, 95%CI -5.6 to -3.5). The pooled meta-analysis of 5 RCTs suggested a 18% relative risk reduction in postoperative morbidity favouring the intervention (RR 0.82, 95%CI 0.52-1.28, p=0.38, I2=0%). Conclusions The feasibility targets of this pilot RCT were not met for recruitment rate, randomization percentage, and complete follow-up. Pooled meta-analysis suggests that LED prior to non-bariatric surgery can effectively induce weight loss with reduced postoperative morbidity, which needs to be validated by a larger noninferiority RCT with additional centers to meet the feasibility targets. Trial Registration Clinicaltrials.gov: NCT03935451