Kenji Okumura1, Abhay Dhand2, Suguru Ohira1. 1. Division of Cardiothoracic Surgery, Department of Surgery, Westchester Medical Center/New York Medical College, Valhalla, New York, USA. 2. Division of Transplant Infectious Disease, Department of Medicine, Westchester Medical Center/New York Medical College, Valhalla, New York, USA.
To the Editor:We read the article by Agarwal et al., in which they used the United Network for Organ Sharing database to reveal that cardiac outcomes in simultaneous kidney-heart transplants (SKHTs) recipients are better when compared with those in heart transplantation-alone recipients. The authors suggest that SKHT offered a significant long-term survival advantage and better cardiac graft outcomes for patients who were on pretransplant dialysis or had an estimated glomerular filtration rate <45 ml/min per 1.73 m2. Nevertheless, we urge caution on interpreting these results, especially in patients with estimated glomerular filtration rate <45 ml/min per 1.73 m2 (Figure 6/7 of the manuscript), because these comparisons were performed using univariable analysis in which various donor/recipient differences may not have been considered.Because the smaller SKHT group was a highly selected population when compared with all heart transplantation-alone patients, we suggest that the authors reanalyze their data using propensity score matching to balance the differences between 2 groups and avoid any potentially misleading conclusions.We analyzed the United Network for Organ Sharing data between 2015 and 2020 (time period when the SKHT increased in volume) using the inverse probability of treatment weighted method to adjust for various pretransplant patient characteristics to provide a potential answer. Our analysis revealed the opposite result: SHKT is a risk factor for cumulative survival during the study period (vs. heart transplantation-alone, adjusted hazard ratio 1.20, 95% CI 1.002–1.440, P = 0.047).Although the frequency of SKHT has been increasing in the United States, consensus is still emerging regarding the best practices. We would like to suggest addresing this potential issue, as it would provide significant insights into their study.