Fate of Living Kidney Donors Who Lost Weight to Become Donors

Associations of obesity with antidiabetic medication use after living kidney donation: An analysis of linked national registry and pharmacy fill records

We examined a novel linkage of national US donor registry data with records from a pharmacy claims warehouse (2007-2016) to examine associations (adjusted hazard ratio, LCL aHRUCL ) of post-donation fills of antidiabetic medications (ADM, insulin or non-insulin agents) with body mass index (BMI) at donation and other demographic and clinical factors. In 28 515 living kidney donors (LKDs), incidence of ADM use at 9 years rose in a graded manner with higher baseline BMI: underweight, 0.9%; normal weight, 2.1%; overweight, 3.5%; obese, 8.5%. Obesity was associated with higher risk of ADM use compared with normal BMI (aHR, 3.36 4.596.27 ). Metformin was the most commonly used ADM and was filled more often by obese than by normal weight donors (9-year incidence, 6.87% vs 1.85%, aHR, 3.55 5.007.04 ). Insulin use was uncommon and did not differ significantly by BMI. Among a subgroup with BMI data at the 1-year post-donation anniversary (n = 19 528), compared with stable BMI, BMI increase >0.5 kg/m2 by year 1 was associated with increased risk of subsequent ADM use (aHR, 1.03 1.482.14, P = .04). While this study did not assess the impact of donation on the development of obesity, these data support that among LKD, obesity is a strong correlate of ADM use.

Implications of excess weight on kidney donation: Long-term consequences of donor nephrectomy in obese donors

BACKGROUND

An elevated body mass index (>30 kg/m²) has been a relative contraindication for living kidney donation; however, such donors have become more common. Given the association between obesity and development of diabetes, hypertension, and end-stage renal disease, there is concern about the long-term health of obese donors.

METHODS

Donor and recipient demographics, intraoperative parameters, complications, and short- and long-term outcomes were compared between contemporaneous donors-obese donors (body mass index ≥30 kg/m²) versus nonobese donors (body mass index <30 kg/m²).

RESULTS

Between the years 1975 and 2014, we performed 3,752 donor nephrectomies; 656 (17.5%) were obese donors. On univariate analysis, obese donors were more likely to be older (P < .01) and African American (P < .01) and were less likely to be a smoker at the time of donation (P = .01). Estimated glomerular filtration rate at donation was higher in obese donors (115 ± 36 mL/min/1.73m²) versus nonobese donors (97 ± 22 mL/min/1.73m²; P < .001). There was no difference between groups in intraoperative and postoperative complications; but intraoperative time was longer for obese donors (adjusted P < .001). Adjusted postoperative length of stay (LOS) was longer (adjusted P = .01), but after adjustment for donation year, incision type, age, sex, and race, there were no differences in short-term (<30 days) and long-term (>30 days) readmissions. Estimated glomerular filtration rate and rates of end-stage renal disease were not significantly different between donor groups >20 years after donation (P = .71). However, long-term development of diabetes mellitus (adjusted hazard ratio (HR) 3.14; P < .001) and hypertension (adjusted hazard ratio (HR) 1.75; P < .001) was greater among obese donors and both occurred earlier (diabetes mellitus: 12 vs 18 years postnephrectomy; hypertension: 11 vs 15 years).

CONCLUSION

Obese donors develop diabetes mellitus and hypertension more frequently and earlier than nonobese donors after donation, raising concerns about increased rates of end-stage renal disease.