Elevated hemoglobin A1c level and bariatric surgery complications

INTRODUCTION: In cardiac and orthopedic surgery, elevated glycosylated hemoglobin (HbA1c) is a modifiable risk factor for postoperative complications. However, in bariatric surgery, there is insufficient evidence to assess the effectiveness of preoperative HbA1c assessment and its association with postoperative complications. The objective of this study was to assess the impact of HbA1c on early postoperative outcomes in bariatric surgery patients.

METHODS: Patients who underwent laparoscopic sleeve gastrectomy and laparoscopic Roux-En-Y Gastric Bypass between 2017 and 2018 were selected for a retrospective review from the metabolic and bariatric surgery accreditation and quality improvement program (MBSAQIP) database. The study population of 118,742 patients was analyzed for our primary outcome which was defined as a composite of any postoperative complications occurring within 30 days. Two groups were defined by HbA1c cutoff: comparison point A (≤ 8% vs > 8%) and comparison point B (≤ 10% vs > 10%). Procedure-related complications were also examined on subgroup analysis. Propensity score matching (PSM) was used with one-to-one matching. The complication rates before and after PSM were calculated and assessed by Fisher's exact test and conditional logistic regression, respectively.

RESULTS: After PSM, demographic and clinical characteristics were all balanced and elevated HbA1C was not associated with worse outcomes. After adjusting for underlying comorbidities, there was no statistically significant difference seen in the composite outcome for comparison point A HbA1C ≤ 8 and HbA1C > 8 (p = 0.22). For comparison point B, patients with HbA1C ≤ 10 had more composite complications compared to patients with HbA1C > 10 (p < 0.001). Also, on subgroup analysis after PSM for procedure-specific complications, patients above the cutoff threshold of 8 did not have worsened composite outcomes (p = 0.58 and 0.89 for sleeve and bypass, respectively). Again, at cutoff threshold of 10, patients in HbA1C ≤ 10 had more composite complications (p = 0.001 and 0.007 for sleeve and bypass, respectively).

CONCLUSION: In this study of bariatric patients, elevated HbA1c > 8% or 10% was not associated with increased postoperative complications. HbA1c lower than 10% was associated with some types of adverse outcomes in this bariatric dataset. More studies are needed to investigate these findings further. A high HbA1c alone may not disqualify a patient from proceeding with bariatric surgery.