Background

Chronic pain is common in patients who seek metabolic and bariatric surgery (MBS) and is associated with less total post-surgical weight loss (%TWL) compared to those without chronic pain. This study further characterized pain location, grade, and catastrophizing and evaluated the impact of these pain dimensions on %TWL, controlling for surgical type and socioeconomic status (SES). Participants (N = 470) were adults who underwent sleeve gastrectomy (78%) or gastric bypass (22%) and completed assessments of demographics, pain location and duration, the Graded Chronic Pain Scale, and the Pain Catastrophizing Scale preoperatively. Chronic pain was defined as pain persisting for >30 days. Weight was measured pre-operatively and 6-, 12-, 18-, and 24-months post-MBS. The sample was primarily female (81%) and racially diverse (48% Black; 39% White). One-third (37.8%) reported preoperative chronic pain localized most frequently to patients' backs, legs, and knees. Pain grade and surgery type, but not SES were related to %TWL. Patients who underwent sleeve gastrectomy had a lower %TWL across post-surgical follow-up. Pain grade was related to %TWL at 6- and 12-months post-MBS (ps<.05), but not at 18- or 24-months. Patients with high pain intensity (Grade 2) had a larger %TWL compared to those with high pain intensity and disability (Grade 4) and those without chronic pain at 6 and 12-months. Higher pain catastrophizing was associated with less %TWL at 6-months, controlling for pain grade (p<.05). Results suggest that pain grade and pain catastrophizing have the strongest impact on weight loss outcomes in the first 6-12 months post-surgery.