Background: Bariatric weight-loss surgery rates are increasing internationally. Endoscopic sleeve gastroplasty (ESG) is a novel, minimally invasive endoscopic procedure thought to mimic some of the effects of a more common surgery, laparoscopic sleeve gastrectomy (LSG). Patient factors affecting procedural choice are unexplored. Objective: This formative study aimed to determine the preoperative and early postoperative characteristics of adults matched for age, sex, and BMI who chose ESG versus LSG. Methods: This prospective cohort study recruited ESG and matched LSG adults in Australia. Preoperative outcomes were medical history, glycemic biomarkers, blood lipids, liver function enzymes, albumin, blood pressure, hepatic steatosis index, the Gastrointestinal Symptom Rating Scale, the Impact of Weight on Quality of Life-Lite questionnaire, and body composition via dual-energy x-ray absorptiometry. Adverse events were recorded preoperatively and up to 2 weeks postoperatively. SPSS was used to test if there were differences between cohorts by comparing means or mean ranks, and binary regression was used to understand how characteristics might predict procedure choice. Results: A total of 50 (including 25 ESG and 25 LSG) patients were recruited, who were primarily White (45/50, 90%) and female (41/50, 82%) with a mean age of 41.7 (SD 9.4) years. Participants had a mean of 4.0 (SD 2.2) active comorbid conditions, with the most common being nonalcoholic fatty liver disease (38/50, 76%), back pain (32/50, 64%), anxiety or depression (24/50, 48%), and joint pain (23/50, 46%). The LSG cohort had higher hemoglobin A1c (5.3%, SD 0.2%) than the ESG cohort (5%, SD 0.2%; P=.008). There was a 2.4 kg/m² difference in median BMI (P=.03) between the groups, but fat and fat-free mass had no meaningful differences. Comparing the LSG and ESG groups showed that the LSG group had lower total quality of life (49.5%, SD 10.6% vs 56.6%, SD 12.7%; P=.045), lower weight-related self-esteem (10.7%, IQR 3.6%-25% vs 25%, IQR 17.9%-39.3%; P=.02), and worse abdominal pain (38.9%, IQR 33.3%-50% vs 53.9%, SD 14.2%, P=.01). For every percent improvement in weight-related self-esteem, the odds for selecting ESG increased by 4.4% (95% CI 1.004-1.085; P=.03). For every percent worsening in hunger pain, the odds for selecting ESG decreased by 3.3% (95% CI 0.944-0.990; P=.004). Conclusions: There was very little evidence that Australian adults who chose an endoscopic versus surgical sleeve had different rates of comorbidities, body fat percentage, or weight-related quality of life. There was evidence against the test hypothesis, that is, there was evidence suggesting that lower self-esteem predicted choosing a more invasive sleeve (ie, LSG rather than ESG). [ABSTRACT FROM AUTHOR]