Short-Term Preoperative Weight Loss and Postoperative Outcomes in Bariatric Surgery

Preoperative weight loss is often encouraged before undergoing weight loss surgery. Controversy remains as to its effect on postoperative outcomes. The aim of this study was to determine what impact short-term preoperative excess weight loss (EWL) has on postoperative outcomes in patients undergoing primary vertical sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB).

All patients who underwent SG (n = 167) or RYGB (n = 188) between 2014 and 2016 and who completed our program-recommended low calorie diet (LCD) for 4 weeks immediately preceding surgery were included. These patients (N = 355) were then divided into 2 cohorts and analyzed according to those who achieved ≥8% EWL (n = 224) during the 4-week LCD period and those who did not (n = 131). Primary endpoints included percent excess weight loss (% EWL) at 1, 3, 6, and 12 months postoperatively.

Patients achieving ≥8% EWL preoperatively experienced a greater % EWL at postoperative month 3 (42.3 ± 13.2% vs 36.1 ± 10.9%, p < 0.001), month 6 (56.0 ± 18.1% vs 47.5 ± 14.1%, p < 0.001), and month 12 (65.1 ± 23.3% vs 55.7 ± 22.2%, p = 0.003). Median operative duration (117 minutes vs 125 minutes; p = 0.061) and mean hospital length of stay (1.8 days vs 2.1 days; p = 0.006) were also less in patients achieving ≥8% EWL. No significant differences in follow-up, readmission, or reoperation rates were seen. Linear regression analysis revealed that patients who achieved ≥8% EWL during the 4-week LCD lost 7.5% more excess weight at postoperative month 12.

Based on these data, preoperative weight loss of ≥8% excess weight, while following a 4-week LCD, is associated with a significantly greater rate of postoperative EWL over 1 year, as well as shorter operative duration and hospital length of stay.