Anthropometric, Functional, and Haemodynamic Changes in Bariatric Surgery Patients Within the Polish KOS-BAR Pathway: A Retrospective Cohort Study.

Background/Objectives: Bariatric surgery is an effective treatment for severe obesity. Although physiotherapy delivered before and after surgery may support functional recovery, evidence describing real-world multidisciplinary bariatric pathways with embedded perioperative physiotherapy remains limited. This study evaluated perioperative changes in anthropometric, functional, and haemodynamic outcomes in adults who completed preoperative and postoperative physiotherapy within the multidisciplinary Polish KOS-BAR bariatric pathway. Methods: We conducted a single-centre retrospective medical-record study at the University Clinical Centre in Gdańsk. The analysis included a complete-case cohort of 91 adults who completed both supervised physiotherapy cycles and had paired outcome data available. Assessments were performed at four time points: before and after prehabilitation (T1-T2) and before and after postoperative rehabilitation (T3-T4). Outcomes included body mass, body mass index (BMI), waist and chest circumference, 6 min walk test (6MWT) distance with Borg-rated exertion, and haemodynamic measures (heart rate, blood pressure, oxygen saturation) recorded before and after the 6MWT. Results: From T1 to T4, body mass decreased by a median of 26.0 kg and BMI by 8.98 kg/m2, with reductions in waist (-19.0 cm) and chest (-13.0 cm) circumference. Exercise tolerance improved (6MWT median change +30.0 m), and post-test perceived exertion decreased (median -1.0 point). Pre-6MWT resting HR, post-6MWT HR, and blood pressure decreased. The 6MWT distance increased after prehabilitation (T1 → T2) and again after postoperative rehabilitation (T3 → T4). Exploratory correlations suggested weak nominal associations between greater weight loss and larger 6MWT improvement (Spearman r = 0.251, p = 0.016) and between BMI reduction and 6MWT improvement (r = 0.226, p = 0.031), but these associations did not remain statistically significant after Bonferroni correction. Conclusions: In this retrospective cohort of programme completers, participation in the multidisciplinary KOS-BAR pathway with embedded preoperative and postoperative physiotherapy was associated with improved anthropometric, functional, perceived-exertion, and haemodynamic outcomes across follow-up. Because of the uncontrolled retrospective design, these findings cannot establish the independent effect of physiotherapy relative to surgery and other components of multidisciplinary care. Prospective controlled studies are needed to clarify causality and long-term durability.