#952 Inference of donor-type proportions among the prevalent kidney-transplant population in the United States

Abstract Background and Aims In the United States, the organ procurement & transplantation network (OPTN) provides publicly reported data on incident kidney-transplant patients, including proportions of patients receiving a living-donor (LD) or deceased-donor (DD) kidney. However, complete, longitudinal information is not available for the prevalent transplant population. Since LD and DD kidney transplantations differ both in frequency and survival prospects, it is unclear how the prevalent LD/DD distribution differs from the incident population. Here, we reconstruct the 2020 prevalent donor-type distribution by biological sex, using extrapolations of historical data on incidence and post-transplantation survival. Method Using annual kidney-transplant survival data from the US Renal Data System for the years 1996–2020 [1, 2], we inferred long-term post-transplantation survival curves per donor type (LD and DD) and biological sex via data fits with exponential and Gompertz-type survival functions. Together with reported annual incidence data by donor type, this enables a reconstruction of the 2020 prevalent kidney-transplant population. Post-2020 datasets were excluded because COVID-19-related changes in survival trends prevent the required extrapolation of earlier data. Results were validated by comparing donor type-pooled results to reported total prevalent counts for 2020, showing a deviation of –3.3% (or a total of –8.1k out of 245.5k) (Fig. 1a). Results The inferred prevalent counts for 2020 were 63.5k female patients and 90.8k male patients with a deceased-donor (DD) kidney transplant and 32.7k female patients and 50.4k male patients with a living-donor (LD) kidney transplant (Fig. 1b). This corresponds to living/deceased-donor ratios of 34% : 66% among female patients (96.2k in total) and 36% : 64% among male patients (141.2k in total). Conclusion Inferred donor-type proportions suggest a 1 : 2 ratio of living- and deceased-donor kidney transplant patients in the United States, largely independent of biological sex, whereas incident LD/DD ratios increased from 1 : 1.8 in 2010 to 1 : 3.5 in 2020 [2] (Fig. 1c). This reflects better graft and patient survival in LD recipients.