Performance of estimated glomerular filtration rate equations in Black living kidney donor candidates.

INTRODUCTION: New estimated glomerular filtration rate (eGFR) equations using serum creatinine and/or cystatin C have been derived to eliminate adjustment by perceived Black ancestry. We sought to analyze the performance of newer eGFR equations among Black living kidney donor candidates. METHODS: Black candidates (n = 64) who had measured iothalamate GFR between January 2015 and October 2021 were included, and eGFR was calculated using race adjusted (eGFRcr2009 and eGFRcr-cys2012) and race unadjusted (eGFRcys2012, eGFRcr2021, and eGFRcr-cys2021) CKD-EPI equations. Bias and accuracy were calculated. RESULTS: The eGFRcr2021 equation had a negative bias of 9 mL/min/1.73 m2 , while other equations showed a modest positive bias. Accuracy within 10% and 30% was greatest using the eGFRcr-cys2021 equation. With the eGFRcr2021 equation, 9.4% of donors with an mGFR > 80 mL/min/1.73 m2 were misclassified as having an eGFR < 80 mL/min/1.73 m2 . eGFR was also compared among 18 kidney donors at 6-24 months post-donation. Post-donation, the percentage of donors with an eGFR < 60 mL/min/1.73 m2 was 44% using the eGFRcr2021 equation compared to 11% using the eGFRcr-cys2021 equation. CONCLUSION: The CKD-EPICr2021 equation appears to underestimate true GFR in Black living donor candidates. Alternatively, compared to CKD-EPICr2021, the CKD-EPICr-CysC2021 equation appears to perform with less bias and improved accuracy.

The Number and Size of Individual Kidney Medullary Pyramids is Associated with Clinical Characteristics, Kidney Biopsy Findings, and CKD Outcomes among Kidney Donors.

SIGNIFICANCE STATEMENT: Segmentation of multiple structures in cross-sectional imaging is time-consuming and impractical to perform manually, especially if the end goal is clinical implementation. In this study, we developed, validated, and demonstrated the capability of a deep learning algorithm to segment individual medullary pyramids in a rapid, accurate, and reproducible manner. The results demonstrate that cortex volume, medullary volume, number of pyramids, and mean pyramid volume is associated with patient clinical characteristics and microstructural findings and provide insights into the mechanisms that may lead to CKD. BACKGROUND: The kidney is a lobulated organ, but little is known regarding the clinical importance of the number and size of individual kidney lobes. METHODS: After applying a previously validated algorithm to segment the cortex and medulla, a deep-learning algorithm was developed and validated to segment and count individual medullary pyramids on contrast-enhanced computed tomography images of living kidney donors before donation. The association of cortex volume, medullary volume, number of pyramids, and mean pyramid volume with concurrent clinical characteristics (kidney function and CKD risk factors), kidney biopsy morphology (nephron number, glomerular volume, and nephrosclerosis), and short- and long-term GFR <60 or <45 ml/min per 1.73 m 2 was assessed. RESULTS: Among 2876 living kidney donors, 1132 had short-term follow-up at a median of 3.8 months and 638 had long-term follow-up at a median of 10.0 years. Larger cortex volume was associated with younger age, male sex, larger body size, higher GFR, albuminuria, more nephrons, larger glomeruli, less nephrosclerosis, and lower risk of low GFR at follow-up. Larger pyramids were associated with older age, female sex, larger body size, higher GFR, more nephrons, larger glomerular volume, more nephrosclerosis, and higher risk of low GFR at follow-up. More pyramids were associated with younger age, male sex, greater height, no hypertension, higher GFR, lower uric acid, more nephrons, less nephrosclerosis, and a lower risk of low GFR at follow-up. CONCLUSIONS: Cortex volume and medullary pyramid volume and count reflect underlying variation in nephron number and nephron size as well as merging of pyramids because of age-related nephrosclerosis, with loss of detectable cortical columns separating pyramids.

Self-reported marijuana use and its effects on overall approval in potential living kidney donors.

BACKGROUND: Past and present substance use is an important part of the psychosocial evaluation of potential living kidney donors (LKDs). Increasing state legalizations and social acceptance of marijuana (MJ) use can create challenges for transplant centers. METHODS: We investigated the frequency of reporting MJ use, and its effect on the LKD evaluation. A retrospective chart review was performed on all living donor candidates from December 2016 to December 2019 for reports of MJ use, both on an electronic intake form and during clinical evaluation with a licensed social worker (SW). Active MJ use was defined as current use or use within 1 year of evaluation. Baseline characteristics between MJ users and non-users were compared at each step of donor evaluation. We explored variables associated with MJ use including additional consults and testing during the donor evaluation. Overall approval and donation rates for living donors with active MJ use were compared to non-users. Additionally, 1-year donor follow-up was compared between the two groups. Results of 1818 living donor candidates who completed the intake form, 132 admitted to active MJ use. Compared to non-users, MJ users were more likely to be younger, male, single, renting a home, and with a lower level of education. Thirty three out of 338 candidates who completed a social work evaluation reported MJ use. Compared to non-users, MJ users were more frequently classified as moderate or high risk on SW evaluation, and often required a toxicology screen or psychiatry visit for clearance to donate. Altogether 24.2% of MJ users versus 9.5% of non-users discontinued their evaluation (p < .01). Altogether 42.4% of MJ users versus 56.1% of non-users donated their kidney (p = .13). For those who donated, MJ users were less likely than non-users to follow up at 1 year (57.1% vs. 83.0, p-value .02). CONCLUSION: MJ users were often asked to complete additional steps in their evaluation before an approval decision was made, which may have led to the higher rate of donor drop out observed in this group. Further research is needed to assess the effects of MJ use on living donor candidacy, as well as any effects of MJ use on long-term donor outcomes.

Failure to Advance Access to Kidney Transplantation over Two Decades in the United States.

BACKGROUND: Extensive research and policies have been developed to improve access to kidney transplantation among patients with ESKD. Despite this, wide variation in transplant referral rates exists between dialysis facilities. METHODS: To evaluate the longitudinal pattern of access to kidney transplantation over the past two decades, we conducted a retrospective cohort study of adult patients with ESKD initiating ESKD or placed on a transplant waiting list from 1997 to 2016 in the United States Renal Data System. We used cumulative incidence models accounting for competing risks and multivariable Cox models to evaluate time to waiting list placement or transplantation (WLT) from ESKD onset. RESULTS: Among the study population of 1,309,998 adult patients, cumulative 4-year WLT was 29.7%, which was unchanged over five eras. Preemptive WLT (prior to dialysis) increased by era (5.2% in 1997-2000 to 9.8% in 2013-2016), as did 4-year WLT incidence among patients aged 60-70 (13.4% in 1997-2000 to 19.8% in 2013-2016). Four-year WLT incidence diminished among patients aged 18-39 (55.8%-48.8%). Incidence of WLT was substantially lower among patients in lower-income communities, with no improvement over time. Likelihood of WLT after dialysis significantly declined over time (adjusted hazard ratio, 0.80; 95% confidence interval, 0.79 to 0.82) in 2013-2016 relative to 1997-2000. CONCLUSIONS: Despite wide recognition, policy reforms, and extensive research, rates of WLT following ESKD onset did not seem to improve in more than two decades and were consistently reduced among vulnerable populations. Improving access to transplantation may require more substantial interventions.

Long-term kidney transplant graft survival-Making progress when most needed.

Current short-term kidney post-transplant survival rates are excellent, but longer-term outcomes have historically been unchanged. This study used data from the national Scientific Registry of Transplant Recipients (SRTR) and evaluated 1-year and 5-year graft survival and half-lives for kidney transplant recipients in the US. All adult (≥18 years) solitary kidney transplants (n = 331,216) from 1995 to 2017 were included in the analysis. Mean age was 49.4 years (SD +/-13.7), 60% male, and 25% Black. The overall (deceased and living donor) adjusted hazard of graft failure steadily decreased from 0.89 (95%CI: 0.88, 0.91) in era 2000-2004 to 0.46 (95%CI: 0.45, 0.47) for era 2014-2017 (1995-1999 as reference). Improvements in adjusted hazards of graft failure were more favorable for Blacks, diabetics and older recipients. Median survival for deceased donor transplants increased from 8.2 years in era 1995-1999 to an estimated 11.7 years in the most recent era. Living kidney donor transplant median survival increased from 12.1 years in 1995-1999 to an estimated 19.2 years for transplants in 2014-2017. In conclusion, these data show continuous improvement in long-term outcomes with more notable improvement among higher-risk subgroups, suggesting a narrowing in the gap for those disadvantaged after transplantation.

Effects of body mass index on kidney transplant outcomes are significantly modified by patient characteristics.

Body mass index (BMI) is a known risk factor associated with kidney transplant outcomes and is incorporated for determining transplant candidate eligibility. However, BMI is a coarse health measure and risks associated with BMI may vary by patient characteristics. We evaluated 296 807 adult (age > 17) solitary kidney transplant recipients from the Scientific Registry of Transplant Recipients (2000-2019). We examined effects of BMI using survival models and tested interactions with recipient characteristics. Overall, BMI demonstrated a "J-Shaped" risk profile with elevated risks for overall graft loss with low BMI and obesity. However, multivariable models indicated interactions between BMI with recipient age, diagnosis, gender, and race/ethnicity. Low BMI was relatively higher risk for older recipients (>60 years), people with type I diabetes, and males and demonstrated no additional risk among younger (18-39) and Hispanic recipients. High BMI was associated with elevated risk for Caucasians and attenuated risk among African Americans and people with type II diabetes. Effects of BMI had variable risks for mortality vs graft loss by recipient characteristics in competing risks models. The association of BMI with posttransplant outcomes is highly variable among kidney transplant recipients. Results are important considerations for personalized care and risk stratification. Findings suggest that transplant contraindications should not be based on absolute BMI thresholds but modified based on patient characteristics.

Kidney Structural Features from Living Donors Predict Graft Failure in the Recipient.

BACKGROUND: Nephrosclerosis, nephron size, and nephron number vary among kidneys transplanted from living donors. However, whether these structural features predict kidney transplant recipient outcomes is unclear. METHODS: Our study used computed tomography (CT) and implantation biopsy to investigate donated kidney features as predictors of death-censored graft failure at three transplant centers participating in the Aging Kidney Anatomy study. We used global glomerulosclerosis, interstitial fibrosis/tubular atrophy, artery luminal stenosis, and arteriolar hyalinosis to measure nephrosclerosis; mean glomerular volume, cortex volume per glomerulus, and mean cross-sectional tubular area to measure nephron size; and calculations from CT cortical volume and glomerular density on biopsy to assess nephron number. We also determined the death-censored risk of graft failure with each structural feature after adjusting for the predictive clinical characteristics of donor and recipient. RESULTS: The analysis involved 2293 donor-recipient pairs. Mean recipient follow-up was 6.3 years, during which 287 death-censored graft failures and 424 deaths occurred. Factors that predicted death-censored graft failure independent of both donor and recipient clinical characteristics included interstitial fibrosis/tubular atrophy, larger cortical nephron size (but not nephron number), and smaller medullary volume. In a subset with 12 biopsy section slides, arteriolar hyalinosis also predicted death-censored graft failure. CONCLUSIONS: Subclinical nephrosclerosis, larger cortical nephron size, and smaller medullary volume in healthy donors modestly predict death-censored graft failure in the recipient, independent of donor or recipient clinical characteristics. These findings provide insights into a graft's "intrinsic quality" at the time of donation, and further support the use of intraoperative biopsies to identify kidney grafts that are at higher risk for failure.

Modest rates and wide variation in timely access to repeat kidney transplantation in the United States.

Success of transplantation is not limited to initial receipt of a donor organ. Many kidney transplant recipients experience graft loss following initial transplantation and the benefits of expedited placement on the waiting list and retransplantation extend to this population. Factors associated with access to repeat transplantation may be unique given experience with the transplant process and prior viability as a candidate. We examined the incidence, risk factors, secular changes, and center-level variation of preemptive relisting or transplantation (PRLT) for kidney transplant recipients in the United States with graft failure (not due to death) using Scientific Registry of Transplant Recipients data from 2007 to 2018 (n = 39 557). Overall incidence of PRLT was 15% and rates of relisting declined over time. Significantly lower PRLT was evident among patients who were African American and Hispanic, males, older, obese, publicly insured, had lower educational attainment, were diabetic, had longer dialysis time prior to initial transplant, shorter graft survival, longer distance to transplant center, and resided in distressed communities. There was significant variation in PRLT by center, median = 13%, 10th percentile = 6%, 90th percentile = 24%. Cumulatively, results indicate that despite prior access to transplantation, incidence of PRLT is modest with pronounced clinical, social, and center-level sources of variation suggesting opportunities to improve preemptive care among patients with failing grafts.

Comparison of high glomerular filtration rate thresholds for identifying hyperfiltration.

BACKGROUND: High glomerular filtration rate (GFR) is often used as a surrogate for single-nephron hyperfiltration. Our objective was to determine the definition for high GFR that best reflects clinical and structural characteristics of hyperfiltration. METHODS: We studied living kidney donors at the Mayo Clinic and Cleveland Clinic. Potential donors underwent evaluations that included measured GFR (mGFR) by iothalamate clearance and estimated GFR (eGFR) by the serum creatinine-based Chronic Kidney Disease-Epidemiology collaboration (CKD-EPI) equation. High GFR was defined by the 95th percentile for each method (mGFR or eGFR) using either overall or age-specific thresholds. High mGFR was defined as both corrected and uncorrected for body surface area. The association of high GFR by each definition with clinical characteristics and radiologic findings (kidney volume) was assessed. In the subset that donated, the association of high GFR with kidney biopsy findings (nephron number and glomerular volume) and single-nephron GFR was assessed. RESULTS: We studied 3317 potential donors, including 2125 actual donors. The overall 95th percentile for corrected mGFR was 134 mL/min/1.73 m2 and for eGFR was 118 mL/min/1.73 m2. The age-based threshold for uncorrected mGFR was 198 mL/min - 0.943×Age, for corrected mGFR it was 164 mL/min/1.73 m2 - 0.730×Age and for eGFR it was 146 mL/min/1.73 m2 - 0.813×Age. High age-based uncorrected mGFR had the strongest associations with higher single-nephron GFR, larger glomerular volume, larger kidney volume, male gender, higher body mass index and higher 24-h urine albumin, but also had the strongest association with high nephron number. A high age-height-gender-based uncorrected mGFR definition performed almost as well but had a weaker association with nephron number and did not associate with male gender. CONCLUSIONS: High age-based uncorrected mGFR showed the most consistent associations reflective of hyperfiltration. However, high age-based uncorrected mGFR has limited clinical utility because it does not distinguish between hyperfiltration and high nephron number.

Dramatic secular changes in prognosis for kidney transplant candidates in the United States.

Over recent decades, numerous clinical advances and policy changes have affected outcomes for candidates of kidney transplantation in the United States. We examined the national Scientific Registry for Transplant Recipients for adult (18+) solitary kidney transplant candidates placed on the waiting list for primary listing from 2001 to 2015. We evaluated rates of mortality, transplantation, and waitlist removal. Among 340 115 candidates there were significant declines in mortality (52 deaths/1000 patient years in 2001-04 vs 38 deaths/1000 patient years in 2012-15) and transplant rates (304 transplants/1000 patient years in 2001-04 vs 212 transplants/1000 patient years in 2012-15) and increases in waitlist removals (15 removals/1000 patient years in 2001-04 vs 25/1000 patient years in 2012-15) within the first year after listing. At 5 years an estimated 37% of candidates listed in 2012-15 were alive without transplant as compared to 22% in 2001-04. Declines in mortality over time were significantly more pronounced among African Americans, candidates with longer dialysis duration, and those with diabetes (P < .001). Cumulatively, results indicate dramatic changes in prognoses for adult kidney transplant candidates, likely impacted by selection criteria, donor availability, regulatory oversight, and clinical care. These trends are important considerations for prospective policy development and research, clinical and patient decision-making, and evaluating the impact on access to care.

Larger nephron size, low nephron number, and nephrosclerosis on biopsy as predictors of kidney function after donating a kidney.

It is unclear whether structural findings in the kidneys of living kidney donors predict postdonation kidney function. We studied living kidney donors who had a kidney biopsy during donation. Nephron size was measured by glomerular volume, cortex volume per glomerulus, and mean cross-sectional tubular area. Age-specific thresholds were defined for low nephron number (calculated from CT and biopsy measures) and nephrosclerosis (global glomerulosclerosis, interstitial fibrosis/tubular atrophy, and arteriosclerosis). These structural measures were assessed as predictors of postdonation measured GFR, 24-hour urine albumin, and hypertension. Analyses were adjusted for baseline age, gender, body mass index, systolic and diastolic blood pressure, hypertension, measured GFR, urine albumin, living related donor status, and time since donation. Of 2673 donors, 1334 returned for a follow-up visit at a median 4.4 months after donation, with measured GFR <60 mL/min/1.73 m2 in 34%, urine albumin >5 mg/24 h in 13%, and hypertension in 5.3%. Larger glomerular volume and interstitial fibrosis/tubular atrophy predicted follow-up measured GFR <60 mL/min/1.73 m2 . Larger cortex volume per glomerulus and low nephron number predicted follow-up urine albumin >5 mg/24 h. Arteriosclerosis predicted hypertension. Microstructural findings predict GFR <60 mL/min/1.73 m2 , modest increases in urine albumin, and hypertension shortly after kidney donation.

Significantly Lower Rates of Kidney Transplantation among Candidates Listed with the Veterans Administration: A National and Local Comparison.

BACKGROUND: The process for evaluating kidney transplant candidates and applicable centers is distinct for patients with Veterans Administration (VA) coverage. We compared transplant rates between candidates on the kidney waiting list with VA coverage and those with other primary insurance. METHODS: Using the Scientific Registry of Transplant Recipients database, we obtained data for all adult patients in the United States listed for a primary solitary kidney transplant between January 2004 and August 2016. Of 302,457 patients analyzed, 3663 had VA primary insurance coverage. RESULTS: VA patients had a much greater median distance to their transplant center than those with other insurance had (282 versus 22 miles). In an adjusted Cox model, compared with private pay and Medicare patients, VA patients had a hazard ratio (95% confidence interval) for time to transplant of 0.72 (0.68 to 0.76) and 0.85 (0.81 to 0.90), respectively, and lower rates for living and deceased donor transplants. In a model comparing VA transplant rates with rates from four local non-VA competing centers in the same donor service areas, lower transplant rates for VA patients than for privately insured patients persisted (hazard ratio, 0.72; 95% confidence interval, 0.65 to 0.79) despite similar adjusted mortality rates. Transplant rates for VA patients were similar to those of Medicare patients locally, although Medicare patients were more likely to die or be delisted after waitlist placement. CONCLUSIONS: After successful listing, VA kidney transplant candidates appear to have persistent barriers to transplant. Further contemporary analyses are needed to account for variables that contribute to such differential transplant rates.

Clinical and Pathology Findings Associate Consistently with Larger Glomerular Volume.

Background Glomerular volume increases when demand exceeds nephron supply, which may lead to glomerulosclerosis. It is unclear if determinants of glomerular volume are consistent between populations that differ by severity of comorbidities.Methods We studied kidney biopsy specimens from living kidney donors (n=2453) and patients who underwent radical nephrectomy for a renal tumor (n=780). We scanned specimen sections into high-resolution digital images, manually traced glomerular profiles, and calculated mean glomerular volumes using the Weibel-Gomez stereologic formula (separately for nonsclerosed glomeruli and globally sclerosed glomeruli). We then assessed the relationship of glomerular volume with age, clinical characteristics, and nephrosclerosis on biopsy specimen.Results Compared with kidney donors, patients with tumors were older and more frequently men, obese, diabetic, or hypertensive, had more glomerulosclerosis and interstitial fibrosis on biopsy specimen, and had 12% larger nonsclerosed glomeruli (P<0.001). In both populations, male sex, taller height, obesity, hypertension, and proteinuria associated with larger nonsclerosed glomeruli to a similar extent. In patients with tumors, diabetes, glomerulosclerosis >25%, and interstitial fibrosis >25% also associated with larger nonsclerosed glomeruli. Independent clinical predictors of larger nonsclerotic glomeruli were family history of ESRD, male sex, taller height, obesity, diabetes, and proteinuria. After adjustment for these characteristics, nonsclerotic glomerular volume did not differ between populations and was stable up to age 75 years, after which it decreased with age. Many of these findings were also evident with globally sclerotic glomerular volume.Conclusions Characteristics associated with glomerular volume are consistent between patient populations with low and high levels of comorbidity.

Residential Area Life Expectancy: Association With Outcomes and Processes of Care for Patients With ESRD in the United States.

BACKGROUND: The effects of underlying noncodified risks are unclear on the prognosis of patients with end-stage renal disease (ESRD). We aimed to evaluate the association of residential area life expectancy with outcomes and processes of care for patients with ESRD in the United States. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: Adult patients with incident ESRD between 2006 and 2013 recorded in the US Renal Data System (n=606,046). PREDICTOR: The primary exposure was life expectancy in the patient's residential county estimated by the Institute for Health Metrics and Evaluation. OUTCOMES: Death, placement on the kidney transplant wait list, living and deceased donor kidney transplantation, and posttransplantation graft loss. RESULTS: Median life expectancies of patients' residences were 75.6 (males) and 80.4 years (females). Compared to the highest life expectancy quintile and adjusted for demographic factors, disease cause, and multiple comorbid conditions, the lowest quintile had adjusted HRs for mortality of 1.20 (95% CI, 1.18-1.22); placement onto the waiting list, 0.68 (95% CI, 0.67-0.70); living donor transplantation, 0.53 (95% CI, 0.51-0.56); posttransplantation graft loss, 1.35 (95% CI, 1.27-1.43); and posttransplantation mortality, 1.29 (95% CI, 1.19-1.39). Patients living in areas with lower life expectancy were less likely to be informed about transplantation, be under the care of a nephrologist, or receive an arteriovenous fistula as the initial dialysis access. Results remained consistent with additional adjustment for zip code-level median income, population size, and urban-rural locality. LIMITATIONS: Potential residual confounding and attribution of effects to individuals based on residential area-level data. CONCLUSIONS: Residential area life expectancy, a proxy for socioeconomic, environmental, genetic, and behavioral factors, was independently associated with mortality and process-of-care measures for patients with ESRD. These results emphasize the underlying effect on health outcomes of the environment in which patients live, independent of patient-level factors. These findings may have implications for provider assessments.

Racial disparity in kidney transplant survival relates to late rejection and is independent of steroid withdrawal.

Black kidney transplant recipients have more acute rejection (AR) and inferior graft survival. We sought to determine whether early steroid withdrawal (ESW) had an impact on AR and death-censored graft loss (DCGL) in blacks. From 2006 to 2012, AR and graft survival were analyzed in 483 kidney recipients (208 black and 275 non-black). Rates of ESW were similar between blacks (65%) and non-blacks (67%). AR was defined as early (≤3 months) or late (>3 months). The impact of black race, early AR, and late AR on death-censored graft failure was analyzed using univariate and multivariate Cox models. Blacks had greater dialysis vintage, more deceased donor transplants, and less HLA matching, yet rates of early AR were comparable between blacks and non-blacks. However, black race was a risk factor for late AR (HR: 3.48 (95% CI: 1.87-6.47)) Blacks had a greater rate of DCGL, partially driven by late AR (HR with late AR: 5.6; 95% CI: 3.3-9.3). ESW had no significant interaction with black race for risk of early AR, late AR, or DCGL. Independent of ESW, black kidney recipients had a higher rate of late AR after kidney transplantation. Late AR was highly predictive of DCGL and contributed to inferior graft survival in blacks.

Morphometric age and survival following kidney transplantation.

BACKGROUND: As patients with chronic kidney disease become older, there is greater need to identify who will most benefit from kidney transplantation. Analytic morphomics has emerged as an objective risk assessment tool distinct from chronologic age. We hypothesize that morphometric age is a significant predictor of survival following transplantation. METHODS: A retrospective cohort of 158 kidney transplant patients from 2005 to 2014 with 1-year preoperative imaging was identified. Based on a control population comprising of trauma patients and kidney donors, morphometric age was calculated using the validated characteristics of psoas area, psoas density, and abdominal aortic calcification. The primary outcome was post-transplant survival. RESULTS: Cox regression showed morphometric age was a significant predictor of survival (hazard ratio, 1.06 per morphometric year [95% confidence interval, 1.03-1.08]; P < .001). Chronological age was not significant (hazard ratio, 1.03 per year [0.98-1.07]; P = .22). Among the chronologically oldest patients, those with younger morphometric age had greater survival rates compared to those with older morphometric age. CONCLUSIONS: Morphometric age predicts survival following kidney transplantation. Particularly for older patients, it offers improved risk stratification compared to chronologic age. Morphomics may improve the transplant selection process and provide a greater assessment of prospective survival benefits.

Using analytic morphomics to describe body composition associated with post-kidney transplantation diabetes mellitus.

BACKGROUND: Better risk assessment tools are needed to predict post-transplantation diabetes mellitus (PTDM). Using analytic morphomic measurements from computed tomography (CT) scans, we aimed to identify specific measures of body composition associated with PTDM. METHODS: We retrospectively reviewed 99 non-diabetic kidney transplant recipients who received pre-transplant CT scans at a single institution between 1/2005 and 5/2014. Analytic morphomic techniques were used to measure abdominal adiposity, abdominal size, and psoas muscle area and density, standardized by gender. We measured the associations of these morphomic factors with PTDM. RESULTS: One-year incidence of PTDM was 18%. The morphomic factors significantly associated with PTDM included visceral fat area (OR=1.84 per standard deviation increase, P=.020), body depth (OR=1.79, P=.035), and total body area (OR=1.67, P=.049). Clinical factors significantly associated with PTDM included African American race (OR=3.01, P=.044), hypertension (OR=2.97, P=.041), and dialysis vintage (OR=1.24 per year on dialysis, P=.048). Body mass index was not associated with PTDM (OR=1.05, P=.188). On multivariate modeling, visceral fat area was an independent predictor of PTDM (OR=1.91, P=.035). CONCLUSIONS: Analytic morphomics can identify pre-transplant measurements of body composition that are predictive of PTDM in kidney transplant recipients. Pre-transplant imaging contains a wealth of underutilized data that may inform PTDM prevention strategies.

Utility of mammography for chronic kidney disease patients undergoing kidney transplant evaluation.

UNLABELLED: Transplant centers typically require screening mammography (MMG) for women ≥40 during evaluation. American Cancer Society recommends starting annual MMG at 40, while USPSTF recommends biennial MMG at 50. We sought to determine the effect of age and other breast malignancy risk factors on screening MMG in the pre-transplant renal failure population undergoing transplant evaluation. METHODS: We retrospectively examined women ≥40 undergoing kidney transplant evaluation from 2006 to 2012 (n = 541). RESULTS: Patients aged 40.0-49.9 and ≥50 had similar rates of breast biopsy and breast malignancy. African Americans underwent a higher rate of biopsies (OR 2.391, 95%CI 1.111-5.019, p = 0.026), with a lower rate of biopsy in those already on dialysis at presentation (OR 0.434, 95%CI 0.212-0.888, p = 0.022). Higher breast density (>50% fibroglandular tissue) increased both rate of biopsy (OR 2.876, 95%CI 1.377-6.010, p = 0.005) and malignancy (OR 5.061, 95%CI 1.012-25.315, p = 0.048). CONCLUSIONS: As we found no independent differences in biopsy or malignancy between age groups, it is reasonable for transplant centers to use the same evaluation MMG screening policy for all women ≥40. However, as malignancy risk increased with higher breast density, a lower threshold for additional workup may be warranted in patients with dense breasts or an indeterminate lesion on MMG.