Characterization of trends in preoperative hemoglobin A1c testing prior to metabolic and bariatric surgery: a retrospective, observational study.

Background: Irrespective of baseline diabetes status, preoperative hemoglobin A1c (A1C) influences perioperative care in patients undergoing metabolic and bariatric surgery (MBS). Accordingly, the American Society of Metabolic and Bariatric Surgery (ASMBS) endorses that patients undergoing MBS should receive a preoperative A1C test. We aimed to assess the proportion of MBS patients who received a preoperative A1C test and determine whether baseline diabetes status influences receipt of a test.

Methods: We queried the 2017 to 2022 MBSAQIP database for patients undergoing open, laparoscopic, or robotic Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy. Using descriptive methods, we compared the clinical and demographic characteristics of patients who received a preoperative A1C test with patients who did not. We performed logistic regression analysis using diabetes status as a predictor variable and receipt of a test as the outcome, covarying for sociodemographic and clinical factors.

Results: We identified 996,217 patients who underwent RYGB or sleeve gastrectomy between 2017 to 2022. The average age of the cohort was 43.8 years (SD = 11.9) and 81.0% were female. Overall, 45.7% received a preoperative A1C test. The proportion who was tested increased over the six-year study period, from 35.5% in 2017 to 56.0% in 2022. Compared to those who were not tested, patients who were tested were more likely to have several cardiopulmonary comorbidities, including COPD (1.4% vs 1.2%, p < 0.001), PE (1.4% vs 1.2%, p < 0.001), sleep apnea (39.3 vs. 36.4%, p < 0.001), HTN (47.1% vs 44.0%, p < 0.001), and MI (1.2% vs. 1.0%, p < 0.001), though the differences in proportions were small and may not be clinically significant. Compared to patients who did not have diabetes or had diabetes controlled by diet alone, patients with non-insulin dependent diabetes had 77% increased odds of receiving a A1C test (adjusted OR (aOR) 1.77, p < 0.001); insulin dependent patients had 113% increased odds (aOR 2.13, p < 0.001).

Conclusion: Despite society recommendations endorsing measurement of preoperative A1C prior to MBS, less than half of patients undergoing MBS between 2017 and 2022 received a preoperative A1C test. Additionally, there were differential patterns in testing based on diabetes status. Preoperative glycemic evaluation is an area for continued quality improvement.