Bariatric surgery and its impact on hemodialysis: A retrospective cohort analysis

To evaluate metabolic and dialysis parameters following bariatric surgery in prospective kidney transplant candidates.

Bariatric surgery has been associated with improved survival among patients receiving dialysis. However, the mechanism to explain this observation remains unclear, especially considering higher body mass index (BMI) has been associated with improved survival on dialysis ("Obesity Paradox") Clarifying how surgery impacts interdialytic weight gain (IDWG), and cardiovascular risk factors, such as systolic blood pressure (SBP) and diabetes is essential.

All adult patients receiving dialysis who underwent bariatric surgery were identified via the Queensland Statewide Bariatric Service. Demographics, co-morbidities, weight, height, and dialysis parameters (pre-dialysis SBP, intradialytic weight gain (IDWG), and calculated ultrafiltration volume) were collected over a three-month pre-surgery and six-month post-surgery from the medical records. Paired T-Tests and Wilcoxon Signed Rank Tests were used as appropriate.

Thirteen patients (mean age 50.3 years; 61.5% female; all on haemodialysis) were identified. Most had type 2 diabetes mellitus (61.5%) and no one had coronary artery disease. Preoperative mean weight and BMI were 129.2 kg and 44.2 kg/m², respectively. Post-operatively, patients lost an average of 29.6 kg (22.9% reduction,95%CI 19.09-40.05) and reduced BMI by 10.4 kg/m² (23.5% reduction,95%CI 6.46-14.32) SBP decreased by 14.2 mmHg (10.3% reduction) (p < 0.001), and IDWG dropped by 1.16 kg (55.5% reduction) (p < 0.001). Calculated ultrafiltration requirements declined by 47.7% (p < 0.001). No significant changes were observed in HbA1c, antihypertensive use, or admissions for fluid overload.

Bariatric surgery was associated with significant improvements in fluid management and blood pressure control in this small cohort. Larger studies are needed to confirm the consistency and generalisability of these findings.