Use of Machine Learning Consensus Clustering to Identify Distinct Subtypes of Black Kidney Transplant Recipients and Associated Outcomes

Importance: Among kidney transplant recipients, Black patients continue to have worse graft function and reduced patient and graft survival. Better understanding of different phenotypes and subgroups of Black kidney transplant recipients may help the transplant community to identify individualized strategies to improve outcomes among these vulnerable groups. Objective: To cluster Black kidney transplant recipients in the US using an unsupervised machine learning approach. Design, Setting, and Participants: This cohort study performed consensus cluster analysis based on recipient-, donor-, and transplant-related characteristics in Black kidney transplant recipients in the US from January 1, 2015, to December 31, 2019, in the Organ Procurement and Transplantation Network/United Network for Organ Sharing database. Each cluster\u27s key characteristics were identified using the standardized mean difference, and subsequently the posttransplant outcomes were compared among the clusters. Data were analyzed from June 9 to July 17, 2021. Exposure: Machine learning consensus clustering approach. Main Outcomes and Measures: Death-censored graft failure, patient death within 3 years after kidney transplant, and allograft rejection within 1 year after kidney transplant. Results: Consensus cluster analysis was performed for 22 687 Black kidney transplant recipients (mean [SD] age, 51.4 [12.6] years; 13 635 men [60%]), and 4 distinct clusters that best represented their clinical characteristics were identified. Cluster 1 was characterized by highly sensitized recipients of deceased donor kidney retransplants; cluster 2, by recipients of living donor kidney transplants with no or short prior dialysis; cluster 3, by young recipients with hypertension and without diabetes who received young deceased donor transplants with low kidney donor profile index scores; and cluster 4, by older recipients with diabetes who received kidneys from older donors with high kidney donor profile index scores and extended criteria donors. Cluster 2 had the most favorable outcomes in terms of death-censored graft failure, patient death, and allograft rejection. Compared with cluster 2, all other clusters had a higher risk of death-censored graft failure and death. Higher risk for rejection was found in clusters 1 and 3, but not cluster 4. Conclusions and Relevance: In this cohort study using an unsupervised machine learning approach, the identification of clinically distinct clusters among Black kidney transplant recipients underscores the need for individualized care strategies to improve outcomes among vulnerable patient groups

Potential barriers to renal patient care: Perspectives of dialysis and transplant social workers.

Background: Little is studied about social workers\u27 (SW) perceptions and experiences in dialysis and transplant care. We aimed to assess patient care experiences and perspectives of SW in dialysis and transplant settings. Methods: In our survey, six care Barriers were identified: Communication (reading, verbal), advance care planning, psychosocial (transportation, vocation, insurance), independence, support system, and cognitive status. Surveys were sent to dialysis (DSW) and transplant (TSW) SW in Michigan to inquire about Barriers perceived. Results were quantified with a 1∼5 scale (1 = most likely). Weighted average and standard error were calculated, and Barriers with significant differences (difference of avg. ≥ 1) were reported. Results: 37 DSW and 7 TSW responded to our survey. DSW frequently noted transportation difficulties and concerns, considered patients\u27 employment status in care plans (psychosocial), modified treatment based on cultural/religious background (support system), and discussed advance care planning; DSW perceived resolving psychosocial Barriers (mobility) and support system as vital for treatment success. However, TSW emphasized “adequate social support” as assistance with medication and compliance, early hands-on help, and caregiver education for post-transplant care. In contrast, DSW deemed “adequate social support” in general terms. (Figure presented) Both DSW and TSW experienced literacy, insurance, and cognitive status Barriers. They both perceived overcoming most Barriers and ensuring patients\u27 cognitive ability as important for treatment success. (Figure presented) Conclusions: Common goals of care plan among DSW and TSW would be beneficial to aid patients transitioning between the two settings and improving overall treatment outcome

Potential Barriers to renal patient care: Perspectives of dialysis and transplant social workers.

Background: Little is studied about social workers\u27 (SW) perceptions and experiences in dialysis and transplant care. We aimed to assess patient care experiences and perspectives of SW in dialysis and transplant settings. Methods: In our survey, six care Barriers were identified: Communication (reading, verbal), advance care planning, psychosocial (transportation, vocation, insurance), independence, support system, and cognitive status. Surveys were sent to dialysis (DSW) and transplant (TSW) SW in Michigan to inquire about Barriers perceived. Results were quantified with a 1∼5 scale (1 = most likely). Weighted average and standard error were calculated, and Barriers with significant differences (difference of avg. ≥ 1) were reported. Results: 37 DSW and 7 TSW responded to our survey. DSW frequently noted transportation diffi culties and concerns, considered patients\u27 employment status in care plans (psychosocial), modified treatment based on cultural/religious background (support system), and discussed advance care planning; DSW perceived resolving psychosocial Barriers (mobility) and support system as vital for treatment success. However, TSW emphasized “adequate social support” as assistance with medication and compliance, early hands-on help, and caregiver education for post-transplant care. In contrast, DSW deemed “adequate social support” in general terms. (Figure presented) Both DSW and TSW experienced literacy, insurance, and cognitive status Barriers. They both perceived overcoming most Barriers and ensuring patients\u27 cognitive ability as important for treatment success. (Figure presented) Conclusions: Common goals of care plan among DSW and TSW would be beneficial to aid patients transitioning between the two settings and improving overall treatment outcome

Polyomavirus Genotypes in Renal Transplant Recipients in the United States

Purpose: BK Polyomavirus (BKV) subtypes and subgroups present uneven geo-graphical distribution, suggesting a potential relationship with ethnicity. In the United States where there is a definite racial and ethnic diversity, the epidemiology of BKV genotypes remains unclear. This meta-analysis was conducted with the aim to assess BKV genotypes among kidney transplant (KTX) recipients. Methods: A comprehensive literature review was conducted utilizing MEDLINE. Embase and Cochrane Database through October 2018 to identify all studies that reported BKV subtypes and/or subgroups in KTx recipients in the United States. Effect estimates from each individual study were extracted and combined using random-effect, generic inverse variance method of DerSimoman and Laird. Results: 8 observational studies with a total of 193 samples (urine, blood, and kidney tissues) from 188 BKV-mfected KTx recipients in the United States were enrolled. The study years ranged from 2001 to 2016. Overall, the pooled estimated percentages of BKV subtypes were 72. 2% (95%CI: 62. 7%-80. 0%) for subtype I, 6. 8%(95%CI: 2. 5%-16. 9%)forsubtypeII, 8. 3% (95%CI: 4. 4%-15. 1%)for subtype III, and 16. 1% (95%CI: 10. 4%-24. 2%) for subtype IV, respectively. While meta-regression analysis demonstrated a significant positive correlation between year of study and the percentage of BKV subtype I (slopes =+0. 1023, P =0. 01), there were no significant correlations between year of study and percentages of BKV subtype II-IV (P \u3e0. 05). Among KTx recipients with BKV subtype I, the pooled estimated percentages of BKV subgroups were 22. 4% (95%CI: 13. 7%-34. 5%) for subgroup la, 30. 6% (95%CI: 17. 7%-47. 5%)for subgroup Ibl, 47. 7% (95%CI: 35. 8%-59. 9%) for subgroup Ib2, and 4. 1% (95%CI: 1. 2%-13. 3%) for subgroup Ic, respectively. Conclusions: BKV subtype I is the most prevalent subtype among KTx recipients in the United States and its percentage seems to increase overtime. Subgroup Ib2 is the most common among BKV subtype I. Further analysis is needed to assess the effect of BKV genotype on the clinical course of BK viremia in KTx

Epidemiology of Parvovirus B19 and Anemia Among Kidney Transplant Recipients

Purpose: Persistent anemia has been described in kidney transplant (KTX) recipients with Parvovirus B19 virus infection. However, epidemiology of Parvovirus B19 and Parvovirus B19-related anemia after KTx remains unclear. The study\u27s aims were 1) to investigate the frequency of Parvovirus B19 infection and 2) to assess the incidence of Parvovirus B19-related anemia in KTx recipients. Methods: Aliterature search for studies that reported the occurrence rate of Parvo-virus B19 infection and/or seroprevalence of Parvovirus B19 inKTx recipientswas conducted using Medline, Embase, and Cochrane Database from inception through October 2018. Effect estimates from the individual study were extracted and combined using random-effect, generic inverse variance method of DerSimonian and Laird. Results: 15 observational studies with a total of 1, 757 KTx patients were enrolled. Overall, the pooled estimated seroprevalence of Parvovirus B19 IgG was 87. 4% (950/oCI: 64. 4°/\u3c, 96. 4%). The pooled estimated occurrence rate of positive Parvovirus B19 DNA in the first year after KTx was 9. 7% (95%CI: 4. 7°/\u3c, 18. 9%). Sensitivity analysis excluding a study (that solely included KTx patients with anemia) was performed, and showed the pooled estimated occurrence rate of positive Parvovirus B19DNAafterKTxof8. 6%(95%CI: 4. 0%-17. 6%). Meta-regression analysis demonstrated no significant correlations between the year of study and occurrence rate of positive Parvovirus B19 DNA (P = 0. 93). Among KTx recipients with positive Parvovirus B19 DNA, the pooled estimated incidence rates of anemia and severe anemiawere37. 6o/o(95o/oCL25. 8o/o-51. 1o/o)and22. 3o/o(7. 1o/\u3c, 51. 9o/o), respectively. Egger\u27s regression asymmetry test was perforated and showed no publication bias in all analyses. Conclusions: Parvovirus B19 infection occurs mostly within the first year post-transplant. The overall estimated occurrence of positive Parvovirus Bl 9 DNA after KTX is 9. 70/0. The estimated incidence of anemia among KTx recipients with positive Parvovirus B19 DNA is 21. 6%. Parvovirus B 19 should be ruled out in cases of persistent anemia after transplant. [Figure Presented]

Is Remote Ischemic Conditioning of Benefit to Patients Undergoing Kidney Transplantation?

Renal ischemia-reperfusion injury (IRI), an inevitable event during kidney transplantation procedure, can result in delayed graft function or even primary nonfunction. In addition to strategies to limit IRI such as advancements in organ allocation systems and preservation of organs, and reduction in cold and warm ischemia time, remote ischemic conditioning (RIC) has attracted much attention in recent years. With promising findings and data suggesting a potential benefit of RIC in animal kidney transplantation models, a few clinical trials have investigated the use of RIC in human kidney transplantation. Unfortunately, the findings from these investigations have been inconclusive due to a number of factors such as diverse time points of RIC, limited sample size, and complexity of kidney transplant patients. This brief commentary aims to discuss the effects of RIC on clinical outcomes and proinflammatory cytokines in patients undergoing kidney transplantation

CLQ Dominant Deposits in Renal Transplant Biopsies Are Not Associated with Allograft Dysfunction

Purpose: Complement deposition in renal allograft biopsies and native kidneys may represent an ongoing inflammatory process. We studied the significance of incidental finding of predominant Clq deposits in the renal allograft biopsies on renal function, proteinuria, and graft survival. Methods: Retrospectively, patients who have undergone renal biopsies either proto-col or for cause were retrieved for the last five years. Eight patients were found to have dominant or codominant Clq deposits. Patients without Clq deposits (n=21) were selected from the same time period as a control group. Demographic data, creatinine, proteinuria, graft survival data were collected from the electronic medical records: Results: Our analysis included 8 cases with predominant Clq deposits and 21 controls without Clq deposits. Cause of end stage renal disease included type 2 diabetes in 4 cases, type 1 diabetes 1 case, 2 cases had chronic GN, 1 case APRT enzyme deficiency. There were no differences in age, duration on dialysis, HLA mismatch. or induction/maintenance immunosuppressive agents. At one year follow up there was no difference in creatinine or incidence of proteinuria. There were no graft loss in the cases. Potentially deceptive pathologic findings included kappa light chain predominance in deposits of 1 case (without glomerular morphologic alterations) and tubuloreticular structures by electron microscopy in another (without clinical evidence of lupus). Conclusions: In this well-characterized cohort of patients with dominant Clq deposits in the mesangium, there was no association with renal allograft dysfunction or proteinuria. In this short follow up there was no effect on allograft survival. We conclude that there is no clinical relevance of isolated predominant Clq deposit in short-term follow-up. This is in line with one other published study. Further studies are needed to look for long-term effects of Clq deposits and if these lesions persist or disappear in subsequent biopsies

CLQ Dominant Deposits in Renal Transplant Biopsies Are Not Associated with Allograft Dysfunction

Purpose: Complement deposition in renal allograft biopsies and native kidneys may represent an ongoing inflammatory process. We studied the significance of incidental finding of predominant Clq deposits in the renal allograft biopsies on renal function, proteinuria, and graft survival. Methods: Retrospectively, patients who have undergone renal biopsies either proto-col or for cause were retrieved for the last five years. Eight patients were found to have dominant or codominant Clq deposits. Patients without Clq deposits (n=21) were selected from the same time period as a control group. Demographic data, creatinine, proteinuria, graft survival data were collected from the electronic medical records: Results: Our analysis included 8 cases with predominant Clq deposits and 21 controls without Clq deposits. Cause of end stage renal disease included type 2 diabetes in 4 cases, type 1 diabetes 1 case, 2 cases had chronic GN, 1 case APRT enzyme deficiency. There were no differences in age, duration on dialysis, HLA mismatch. or induction/maintenance immunosuppressive agents. At one year follow up there was no difference in creatinine or incidence of proteinuria. There were no graft loss in the cases. Potentially deceptive pathologic findings included kappa light chain predominance in deposits of 1 case (without glomerular morphologic alterations) and tubuloreticular structures by electron microscopy in another (without clinical evidence of lupus). Conclusions: In this well-characterized cohort of patients with dominant Clq deposits in the mesangium, there was no association with renal allograft dysfunction or proteinuria. In this short follow up there was no effect on allograft survival. We conclude that there is no clinical relevance of isolated predominant Clq deposit in short-term follow-up. This is in line with one other published study. Further studies are needed to look for long-term effects of Clq deposits and if these lesions persist or disappear in subsequent biopsies