Armando Rosales, MD, Enrique Elli, MD, Scott Lynch, MD, Gretchen Ames, PhD, Steven P Bowers, MD. Mayo Clinic Florida
Introduction: The respiratory coefficient (RQ), as determined by indirect calorimetry, classifies diet as being carbohydrate rich (RQ=0.7-0.8), fat rich (RQ=0.9-1.0) or overfeeding (RQ>1). We hypothesized that preoperative RQ may be associated with weight-loss outcomes after bariatric surgery.
Methods: From 2016 to 2018, under IRB approval, 137 obese patients were enrolled in a Bariatric Registry and underwent dietary and behavioral counseling, followed by preoperative indirect calorimetry. Resting Energy Expenditure (REE) and respiratory quotient (RQ) of all patients was directly measured. Patients were classified as over-feeders (OF, N=42, 31%) with RQ>1 or non-over-feeders (NOF, N=95, 69%) with RQ<1 (Figure 1). At baseline, there was no difference between groups in gender [female: 105 (76.6%) and male: 32 (23.4%)], mean age (47.1±13.0 yrs), body mass index (BMI, OF: 46.8±7.8 vs. NOF: 44.8±7.4 kg/m2, p=0.40) or baseline REE (OF: 1897±622 vs. NOF: 1874±579, p=0.74). Patients underwent Roux-en-Y gastric bypass (73, 53.28%) or sleeve gastrectomy (64, 46.72%) and were followed clinically for one year. At 6-mo follow-up 94 patients [53.28%; OF: 35(25.55%), NOF: 59(43.06%)] were seen and 48 [35.03%; OF: 59(43.06%) and NOF: 25(18.25%)] at 12-month follow-up. Statistical analysis was performed with SAS 9.4, depending on distribution chi square or T-test was performed.
Results: At one year postoperatively, the OF group had a significantly higher BMI (OF: 34.3±6.5 kg/m2 vs NOF: 29.3±5.1, p=0.009). Differences in weight were not significant at 6mo (OF: 36.0±6.5 vs. NOF: 33.5±5.9 kg/m2, p=0.07). There was no association of operation type to weight outcomes in the OF and NOF groups.
Conclusion: Evidence of overfeeding in the preoperative period prior to bariatric surgery is associated with higher resultant BMI at one year. Calculation of the respiratory coefficient with indirect calorimetry has prognostic significance in bariatric surgery. It is unclear if overfeeding is purely behavioral or secondary to potentially reversible metabolic etiology.
Presented at the SAGES 2017 Annual Meeting in Houston, TX.
Abstract ID: 95188
Program Number: S112
Presentation Session: Bariatric III – Optimizing Care and Pathways
Presentation Type: Podium