Introduction: Living kidney donors remain at low risk of end stage kidney disease but obese and overweight donors' risk is increased. We aimed to describe the trajectory of weight changes pre/post donation to aid in donor risk assessment.
Methods: A single center retrospective chart review from 1/2009-12/2017 was performed. Demographics, height and weight measures from hospital and clinic visits were collected. Patients were categorized by BMI (kg/m²) at time of donation. Mean weight at time of initial assessment, kidney donation, 12 mos follow-up and last follow-up were calculated. Paired t-tests compared mean differences in weight at kidney donation relative to other time points.
Results: 195 donors were included for analysis. Mean (SD) age was 47±13 years and 73% were female. At donation, 2 patients (1.0%) had BMI <18.5 kg/m² (underweight); 49 (25.1%) BMI 18.5-24.9 (healthy weight); 85 (43.6%) BMI 25-29.9 (overweight); 46 (23.6%) BMI 30-34.9 (Class 1 Obesity); 13 (6.7%) BMI 35-39.9 (Class 2 Obesity). Weight loss occurred prior to donation in the BMI 18.5-24.9 group and did not change post-donation.  Significant weight gain occurred following donation in patients with BMI ≥ 25 (P<0.0001).
Conclusions: Despite KDIGO recommendations that obese and overweight patients pursue weight loss before donation and donors maintain a healthy weight after donation, this is not what occurred. Significant weight gain occurred in patients with BMI ≥ 25 at donation. This finding may influence donor risk assessment. Our results highlight the need for effective weight loss interventions both pre- and post-donation.