Diabetes Control and the Risks of ESRD and Mortality in Patients With CKD

BACKGROUND

Diabetes is the leading cause of end-stage renal disease (ESRD) and a significant contributor to mortality in the general population. We examined the associations of hemoglobin A1c (HbA1c) levels with ESRD and death in a population with diabetes and chronic kidney disease (CKD).

STUDY DESIGN

Cohort study.

SETTING & PARTICIPANTS

6,165 patients with diabetes (treated with oral hypoglycemic agents and/or insulin) and CKD stages 1 to 5 at a large health care system.

PREDICTOR

HbA1c level (examined as a categorical and continuous measure).

OUTCOMES

All-cause and cause-specific mortality ascertained from the Ohio Department of Health mortality files and ESRD ascertained from the US Renal Data System.

RESULTS

During a median 2.3 years of follow-up, 957 patients died (887 pre-ESRD deaths) and 205 patients reached ESRD. In a Cox proportional hazards model, after multivariable adjustment including for kidney function, HbA1c level < 6% was associated with higher risk for death when compared with HbA1c levels of 6% to 6.9% (HR, 1.23; 95% CI, 1.01-1.50). Similarly, HbA1c level ≥ 9% was associated with higher risk for all-cause death (HR, 1.34; 95% CI, 1.06-1.69). In competing-risk models, baseline HbA1c level was not associated with ESRD. For cause-specific mortality, diabetes accounted for >12% of deaths overall and >19% of deaths among those with HbA1c levels > 9%.

LIMITATIONS

Small proportion of participants with advanced kidney disease; single-center population.

CONCLUSIONS

In this cohort of patients with CKD with diabetes, HbA1c levels < 6% and ≥9% were associated with higher risk for death. HbA1c levels were not associated with ESRD in this specific CKD population. Diabetes-related deaths increased with higher HbA1c levels.

Predictive Accuracy of a Perioperative Laboratory Test-Based Prediction Model for Moderate to Severe Acute Kidney Injury After Cardiac Surgery

IMPORTANCE

Effective treatment of acute kidney injury (AKI) is predicated on timely diagnosis; however, the lag in the increase in serum creatinine levels after kidney injury may delay therapy initiation.

OBJECTIVE

To determine the derivation and validation of predictive models for AKI after cardiac surgery.

DESIGN, SETTING, AND PARTICIPANTS

Multivariable prediction models were derived based on a retrospective observational cohort of adult patients undergoing cardiac surgery between January 2000 and December 2019 from a US academic medical center (n = 58 526) and subsequently validated on an external cohort from 3 US community hospitals (n = 4734). The date of final follow-up was January 15, 2020.

EXPOSURES

Perioperative change in serum creatinine and postoperative blood urea nitrogen, serum sodium, potassium, bicarbonate, and albumin from the first metabolic panel after cardiac surgery.

MAIN OUTCOMES AND MEASURES

Area under the receiver-operating characteristic curve (AUC) and calibration measures for moderate to severe AKI, per Kidney Disease: Improving Global Outcomes (KDIGO), and AKI requiring dialysis prediction models within 72 hours and 14 days following surgery.

RESULTS

In a derivation cohort of 58 526 patients (median [IQR] age, 66 [56-74] years; 39 173 [67%] men; 51 503 [91%] White participants), the rates of moderate to severe AKI and AKIrequiring dialysis were 2674 (4.6%) and 868 (1.48%) within 72 hours and 3156 (5.4%) and 1018 (1.74%) within 14 days after surgery. The median (IQR) interval to first metabolic panel from conclusion of the surgical procedure was 10 (7-12) hours. In the derivation cohort, the metabolic panel-based models had excellent predictive discrimination for moderate to severe AKI within 72 hours (AUC, 0.876 [95% CI, 0.869-0.883]) and 14 days (AUC, 0.854 [95% CI, 0.850-0.861]) after the surgical procedure and for AKI requiring dialysis within 72 hours (AUC, 0.916 [95% CI, 0.907-0.926]) and 14 days (AUC, 0.900 [95% CI, 0.889-0.909]) after the surgical procedure. In the validation cohort of 4734 patients (median [IQR] age, 67 (60-74) years; 3361 [71%] men; 3977 [87%] White participants), the models for moderate to severe AKI after the surgical procedure showed AUCs of 0.860 (95% CI, 0.838-0.882) within 72 hours and 0.842 (95% CI, 0.820-0.865) within 14 days and the models for AKI requiring dialysis and 14 days had an AUC of 0.879 (95% CI, 0.840-0.918) within 72 hours and 0.873 (95% CI, 0.836-0.910) within 14 days after the surgical procedure. Calibration assessed by Spiegelhalter z test showed P >.05 indicating adequate calibration for both validation and derivation models.

CONCLUSIONS AND RELEVANCE

Among patients undergoing cardiac surgery, a prediction model based on perioperative basic metabolic panel laboratory values demonstrated good predictive accuracy for moderate to severe acute kidney injury within 72 hours and 14 days after the surgical procedure. Further research is needed to determine whether use of the risk prediction tool improves clinical outcomes.

Integrating APOL1 Gene Variants Into Renal Transplantation: Considerations Arising From the American Society of Transplantation Expert Conference

Thirteen percent of individuals of African ancestry express two variant copies of the gene encoding apolipoprotein 1 (APOL1) that has been associated with an increased risk of end-stage renal disease (ESRD) in the general population. Limited studies suggest that the survival of transplanted kidneys from donors expressing two APOL1 risk alleles is inferior to that of kidneys from donors with zero or one risk allele. In living kidney donation, two case reports describe donors expressing two APOL1 risk alleles who developed ESRD. Given the potential impact of APOL1 variants on the utility and safety of kidney transplantation and living kidney donation, the American Society of Transplantation convened a meeting with the goals of summarizing the current state of knowledge with respect to transplantation and APOL1, identifying knowledge gaps and studies to address these gaps, and considering approaches to integrating APOL1 into clinical practice. The authors recognize that current data are not sufficient to support traditional evidence-based guidelines but also recognize that it may require several years to generate the necessary data. Thus, approaches as to how APOL1 might currently be integrated into the clinical decision-making process were considered. This report summarizes the group's deliberations.

Risk factors for retransplant kidney recipients: relisting and outcomes from patients' primary transplant

As of November 2013, 14.5% of the waitlist for a donor kidney comprised patients awaiting a retransplant. We performed a retrospective cohort study of 11,698 adult solitary kidney recipients using national Scientific Registry of Transplant Recipients data transplanted between 2002 and 2011. The aim was to investigate whether outcomes from patients' initial transplants are significant risk factors for patients' repeat transplants or for likelihood of relisting after a failed primary transplant. Retransplant recipients were more likely to be treated for acute rejection [adjusted odds ratio (AOR), 95% confidence interval (CI) = 1.26 (1.07-1.48), p = 0.0053] or hospitalized (AOR = 1.19, 95% CI 1.08-1.31, p = 0.0005) within a year of retransplantation if these outcomes were experienced within a year of primary transplant. Delayed graft function following primary transplants was associated with 35% increased likelihood of recurrence (AOR = 1.35, 95% CI = 1.18-1.54, p < 0.0001). An increase in 1-year GFR after primary transplant was associated with GFR 1 year postretransplant (β = 6.82, p < 0.0001), and retransplant graft failure was inversely associated with 1-year primary transplant GFR (adjusted hazard ratio = 0.74, 95% CI = 0.71-0.76 per 10 mL/min/1.73 m(2) ). A decreased likelihood for relisting was associated with hospitalization and higher GFR following primary transplantation. The increasing numbers of individuals requiring retransplants highlights the importance of incorporating prior transplant outcomes data to better inform relisting decisions and prognosticating retransplant outcomes.

Major Variation across Local Transplant Centers in Probability of Kidney Transplant for Wait-Listed Patients

BACKGROUND

Geographic disparities in access to deceased donor kidney transplantation persist in the United States under the Kidney Allocation System (KAS) introduced in 2014, and the effect of transplant center practices on the probability of transplantation for wait-listed patients remains unclear.

METHODS

To compare probability of transplantation across centers nationally and within donation service areas (DSAs), we conducted a registry study that included all United States incident adult kidney transplant candidates wait listed in 2011 and 2015 (pre-KAS and post-KAS cohorts comprising 32,745 and 34,728 individuals, respectively). For each center, we calculated the probability of deceased donor kidney transplantation within 3 years of wait listing using competing risk regression, with living donor transplantation, death, and waiting list removal as competing events. We examined associations between center-level and DSA-level characteristics and the adjusted probability of transplant.

RESULTS

Candidates received deceased donor kidney transplants within 3 years of wait listing more frequently post-KAS (22%) than pre-KAS (19%). Nationally, the probability of transplant varied 16-fold between centers, ranging from 4.0% to 64.2% in the post-KAS era. Within DSAs, we observed a median 2.3-fold variation between centers, with up to ten-fold and 57.4 percentage point differences. Probability of transplantation was correlated in the post-KAS cohort with center willingness to accept hard-to-place kidneys (r=0.55, P<0.001) and local organ supply (r=0.44, P<0.001).

CONCLUSIONS

Large differences in the adjusted probability of deceased donor kidney transplantation persist under KAS, even between centers working with the same local organ supply. Probability of transplantation is significantly associated with organ offer acceptance patterns at transplant centers, underscoring the need for greater understanding of how centers make decisions about organs offered to wait-listed patients and how they relate to disparities in access to transplantation.

Low-dose rapamycin (sirolimus) effects in autosomal dominant polycystic kidney disease: an open-label randomized controlled pilot study

BACKGROUND AND OBJECTIVES

The two largest studies of mammalian target of rapamycin inhibitor treatment of autosomal dominant polycystic kidney disease (ADPKD) demonstrated no clear benefit on the primary endpoint of total kidney volume (TKV) or on eGFR. The present study evaluated two levels of rapamycin on the 12-month change in (125)I-iothalamate GFR (iGFR) as the primary endpoint and TKV secondarily.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In a 12-month open-label pilot study, 30 adult patients with ADPKD were randomly assigned to low-dose (LD) rapamycin (rapamycin trough blood level, 2-5 ng/ml) (LD group, n=10), standard-dose (STD) rapamycin trough level (>5-8 ng/ml) (STD group, n=10), or standard care (SC group, n=10). They were evaluated with iGFR and noncontrast computed tomography.

RESULTS

Change in iGFR at 12 months was significantly higher in the LD group (7.7±12.5 ml/min per 1.73 m(2); n=9) than in the SC group (-11.2 ± 9.1 ml/min per 1.73 m(2); n=9) (LD versus SC: P<0.01). Change in iGFR at 12 months in the STD group (1.6 ± 12.1 ml/min per 1.73 m(2); n=8) was not significantly greater than that in the SC group (P=0.07), but it was in the combined treatment groups (LD+STD versus SC: P<0.01). Neither eGFR calculated by the CKD-Epidemiology Collaboration equation nor TKV (secondary endpoint) changed significantly from baseline to 12 months in any of the groups. On the basis of results of the mixed model, during the study, patients in the LD group had significantly lower trough blood levels of rapamycin (mean range ± SD, 2.40 ± 0.64 to 2.90 ± 1.20 ng/ml) compared with those in the STD group (3.93 ± 2.27 to 5.77 ± 1.06 ng/ml) (P<0.01).

CONCLUSION

Patients with ADPKD receiving LD rapamycin demonstrated a significant increase in iGFR compared with those receiving standard care, without a significant effect on TKV after 12 months.

Does Survival on the Heart Transplant Waiting List Depend on the Underlying Heart Disease?

OBJECTIVES

The aim of this study was to identify differences in survival on the basis of type of heart disease while awaiting orthotopic heart transplantation (OHT).

BACKGROUND

Patients with restrictive cardiomyopathy (RCM), congenital heart disease (CHD), or hypertrophic cardiomyopathy (HCM) may be at a disadvantage while awaiting OHT because they often are poor candidates for mechanical circulatory support and/or inotropes.

METHODS

The study included all adults in the Scientific Registry of Transplant Recipients database awaiting OHT from 2004 to 2014, and outcomes were evaluated on the basis of type of heart disease. The primary endpoint was time to all-cause mortality, censored at last patient follow-up and time of transplantation. Multivariate Cox proportional hazards modeling was performed to evaluate survival by type of cardiomyopathy.

RESULTS

There were 14,447 patients with DCM, 823 with RCM, 11,799 with ischemic cardiomyopathy (ICM), 602 with HCM, 964 with CHD, 584 with valvular disease, and 1,528 in the "other" category (including 1,216 for retransplantation). During median follow-up of 3.7 months, 4,943 patients died (1,253 women, 3,690 men). After adjusting for possible confounding variables including age, renal function, inotropes, mechanical ventilation, and mechanical circulatory support, the adjusted hazard ratios by diagnoses relative to DCM were 1.70 for RCM (95% confidence interval [CI]: 1.43 to 2.02), 1.10 for ICM (95% CI: 1.03 to 1.18), 1.23 for HCM (95% CI: 0.98 to 1.54), 1.30 for valvular disease (95% CI: 1.07 to 1.57), 1.37 for CHD (95% CI: 1.17 to 1.61), and 1.51 for "other" diagnoses (95% CI: 1.34 to 1.69). Sex was a significant modifier of mortality for ICM, RCM, and "other" diagnoses (p < 0.05 for interaction).

CONCLUSIONS

In the United States, patients with RCM, CHD, or prior heart transplantation had a higher risk for death while awaiting OHT than patients with DCM, ICM, HCM, or valvular heart disease.

Sex Differences in Mortality Based on United Network for Organ Sharing Status While Awaiting Heart Transplantation

BACKGROUND

There are sex differences in mortality while awaiting heart transplantation, and the reason remains unclear.

METHODS AND RESULTS

We included all adults in the Scientific Registry of Transplant Recipients placed on the heart transplant active waitlist from 2004 to 2015. The primary end point was all-cause mortality. Multivariable Cox proportional hazards models were performed to evaluate survival by United Network for Organ Sharing (UNOS) status at the time of listing. Random survival forest was used to identify sex interactions for the competing risk of death and transplantation. There were 33 069 patients (25% women) awaiting heart transplantation. This cohort included 7681 UNOS status 1A (26% women), 13 027 UNOS status 1B (25% women), and 12 361 UNOS status 2 (26% women). During a median follow-up of 4.3 months, 1351 women and 4052 men died. After adjusting for >20 risk factors, female sex was associated with a significant risk of death among UNOS status 1A (adjusted hazard ratio, 1.14; 95% confidence interval, 1.01-1.29) and UNOS status 1B (adjusted hazard ratio, 1.17; 95% confidence interval, 1.05-1.30). In contrast, female sex was significantly protective for time to death among UNOS status 2 (adjusted hazard ratio, 0.85; 95% confidence interval, 0.76-0.95). Sex differences in probability of transplantation were present for every UNOS status, and >20 sex interactions were identified for mortality and transplantation.

CONCLUSIONS

When stratified by initial UNOS status, women had a higher mortality than men as UNOS status 1 and a lower mortality as UNOS status 2. With >20 sex interactions for mortality and transplantation, further evaluation is warranted to form a more equitable allocation system.

Obstructive and Restrictive Lung Function Measures and CKD: National Health and Nutrition Examination Survey (NHANES) 2007-2012

BACKGROUND

Prevalence and factors associated with obstructive and restrictive lung function in people with chronic kidney disease (CKD) are unknown.

STUDY DESIGN

Cross-sectional and longitudinal analyses.

SETTING & PARTICIPANTS

Participants aged 40 to 79 years from NHANES (National Health and Nutrition Examination Survey) 2007 to 2012 who underwent spirometry testing.

PREDICTOR

CKD (estimated glomerular filtration rate [eGFR] >15-<60mL/min/1.73m(2) or urinary albumin-creatinine ratio ≥ 30mg/g).

OUTCOMES

Restrictive lung function (defined as FEV1/FVC≥0.70 and baseline FVC<80% predicted), obstructive lung function (defined as FEV1/FVC<0.70 based on postbronchodilator spirometric results), and mortality data (available for 2007-2008 and 2009-2010 survey periods).

RESULTS

7,610 participants (CKD=1,338; non-CKD=6,272) were included. Prevalences of obstructive lung function adjusted to the mean age of 55 years and 50% men in the CKD and non-CKD groups were 15.6% and 13.3%, respectively (P=0.2). Similarly, adjusted prevalences of restrictive lung function in the CKD and non-CKD groups were 9.8% and 6.7%, respectively (P=0.01). Presence of albumin-creatinine ratio ≥ 30mg/g was associated with obstructive (OR, 1.42; 95% CI, 1.07-1.88) and restrictive lung function (OR, 1.43; 95% CI, 1.01-2.03) in the entire study cohort. eGFR<60mL/min/1.73m(2) was associated with higher odds of obstructive lung function. In a multivariable Cox model, age (HR, 1.07; 95% CI, 1.04-1.11) and presence of obstructive lung function (HR, 2.68; 95% CI, 1.80-3.97), but not CKD measures, were associated with death.

LIMITATIONS

Small proportion of participants with advanced kidney disease.

CONCLUSIONS

In a representative sample of US adults, impaired lung function is common in those with and without CKD. Albuminuria was independently associated with both obstructive and restrictive lung function, and eGFR<60mL/min/1.73m(2) was associated with higher odds of obstructive lung function. Older age and obstructive lung function were associated with higher likelihood of death. Further studies examining the burden of lung disease in advanced CKD are needed.

COVID-19-Associated Mortality among Kidney Transplant Recipients and Candidates in the United States

BACKGROUND AND OBJECTIVES

The coronavirus disease 2019 (COVID-19) pandemic has had a profound effect on transplantation activity in the United States and globally. Several single-center reports suggest higher morbidity and mortality among candidates waitlisted for a kidney transplant and recipients of a kidney transplant. We aim to describe 2020 mortality patterns during the COVID-19 pandemic in the United States among kidney transplant candidates and recipients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using national registry data for waitlisted candidates and kidney transplant recipients collected through April 23, 2021, we report demographic and clinical factors associated with COVID-19-related mortality in 2020, other deaths in 2020, and deaths in 2019 among waitlisted candidates and transplant recipients. We quantify excess all-cause deaths among candidate and recipient populations in 2020 and deaths directly attributed to COVID-19 in relation to prepandemic mortality patterns in 2019 and 2018.

RESULTS

Among deaths of patients who were waitlisted in 2020, 11% were attributed to COVID-19, and these candidates were more likely to be male, obese, and belong to a racial/ethnic minority group. Nearly one in six deaths (16%) among active transplant recipients in the United States in 2020 was attributed to COVID-19. Recipients who died of COVID-19 were younger, more likely to be obese, had lower educational attainment, and were more likely to belong to racial/ethnic minority groups than those who died of other causes in 2020 or 2019. We found higher overall mortality in 2020 among waitlisted candidates (24%) than among kidney transplant recipients (20%) compared with 2019.

CONCLUSIONS

Our analysis demonstrates higher rates of mortality associated with COVID-19 among waitlisted candidates and kidney transplant recipients in the United States in 2020.

Uric acid levels have no significant effect on renal function in adult renal transplant recipients: evidence from the symphony study

BACKGROUND AND OBJECTIVES

Uric acid (UA) has been linked to renal damage in experimental models of kidney failure. In humans, no definitive link between UA and renal function has been established, but several epidemiologic studies have suggested that higher UA levels are associated with accelerated loss of renal function, higher incidence of dialysis, and death. Many of the associations have been limited by the colinearity between UA levels and renal function. Renal transplantation is no exception, and limited information is available concerning the independent role of UA on progression of renal function in transplant recipients.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

We investigated the association between UA and renal function progression during the first 3 yr after transplantation, adjusted for baseline renal function, in 1645 patients who were enrolled in the Symphony study.

RESULTS

When corrected for baseline renal function, UA levels 1 mo after transplantation were not associated with 3-yr renal function (P = 0.62). There was a strong colinearity between calculated renal function and UA levels 1 mo after transplantation. In fact, when not corrected for baseline renal function, there was a significant association between UA and renal function at 3 yr (P = 0.005).

CONCLUSIONS

Low renal function is associated with higher UA levels, but higher UA levels are not independently associated with progression of renal dysfunction after kidney transplantation.

Effects of High-Risk Kidneys on Scientific Registry of Transplant Recipients Program Quality Reports

There is a perception that transplanting high-risk kidneys causes programs to be identified as underperforming, thereby increasing the frequency of discards and diminishing access to transplant. Thus, the Organ Procurement and Transplantation Network (OPTN) has considered excluding transplants using kidneys from donors with high Kidney Donor Profile Index (KDPI) scores (≥0.85) when assessing program performance. We examined whether accepting high-risk kidneys (KDPI ≥0.85) for transplant yields worse outcome evaluations. Despite a clear relationship between KDPI and graft failure and mortality, there was no relationship between a program's use of high-KDPI kidneys and poor performance evaluations after risk adjustment. Excluding high-KDPI donor transplants from the June 2015 evaluations did not alter the programs identified as underperforming, because in every case underperforming programs also had worse-than-expected outcomes among lower-risk donor transplants. Finally, we found that hypothetically accepting and transplanting additional kidneys with KDPI similar to that of kidneys currently discarded would not adversely affect program evaluations. Based on the study findings, there is no evidence that programs that accept higher-KDPI kidneys are at greater risk for low performance evaluations, and risk aversion may limit access to transplant for candidates while providing no measurable benefit to program evaluations.

Uric acid: a novel risk factor for acute kidney injury in high-risk cardiac surgery patients?

BACKGROUND

Uric acid has been reported to be a risk factor for the development of chronic kidney disease; however, no study has examined whether uric acid may confer a risk for acute kidney injury.

METHODS

We investigated the relation between serum uric acid and the incidence of postoperative acute kidney injury in patients undergoing high-risk cardiovascular surgery (cardiac valve and aneurysm surgery).

RESULTS

Following cardiovascular surgery, 18 of 58 patients (31%) developed acute kidney injury, with 11 of 24 (45.8%) in the elevated uric acid group (defined as >6 mg/dl) and 7 of 34 (20.5%) in the normal uric acid group (p = 0.05). After controlling for baseline renal function, left ventricular ejection fraction, use of nesiritide, type of surgery, and history of previous surgery, an elevated preoperative uric acid conferred a 4-fold risk for acute kidney injury (OR: 3.98, CI: 1.10-14.33, p = 0.035) and longer hospital stay (36.35 vs. 24.66 days, p = 0.009).

CONCLUSION

This preliminary study suggests that uric acid may be a novel risk factor for acute kidney injury in patients undergoing high-risk cardiovascular surgery.

The relationship between circulating natural killer cells after reduced intensity conditioning hematopoietic stem cell transplantation and relapse-free survival and graft-versus-host disease

BACKGROUND

Natural killer cells are known to have anti-tumor activity in haploidentical hematopoietic stem cell transplantation. We hypothesized that reconstituted circulating natural killer cells may be associated with improved relapse-free survival after HLA-matched hematopoietic stem cell transplantation.

DESIGN AND METHODS

Serial peripheral blood absolute natural killer cell counts were prospectively measured by flow cytometry of lymphocytes expressing CD56 and CD16 in 167 patients. Cluster analysis was used at engraftment and 60 days post-transplant to distinguish patients with high and low absolute natural killer cell counts. At engraftment 80 patients had high counts (> 22.2/mm3) and 43 had low counts. At 60 days post-transplant 84 patients had high counts (> 18.2/mm3) and 38 had low counts. The primary study end-points were death, relapse and acute graft-versus-host disease. The median follow-up was 373 days (range, 67-1767).

RESULTS

Among patients given reduced intensity conditioning, a low absolute natural killer cell count at 60 days post-transplant was independently associated with relapse [adjusted hazard ratio (AHR) = 28.4, 95% confidence interval (CI) 4.3-186.4] and death (AHR = 17.5, 95% CI 4.3-71.3). Furthermore, patients given reduced intensity conditioning who had a high absolute natural killer cell count at 60 days had a significantly better 1-year survival than those with a low count by Kaplan-Meier analysis (83% vs. 11%, p<0.001). Multivariate analysis confirmed that low 60-day absolute natural killer count in patients given reduced intensity conditioning was independently associated with an increase in relapse or death (AHR = 20.22, 95% CI 4.76-85.40). In contrast, there was no significant association between 60-day absolute natural killer cell counts and clinical outcomes in patients receiving myeloablative conditioning. There was no significant association between absolute natural killer cell count and graft-versus-host disease.

CONCLUSIONS

High natural killer cell reconstitution is associated with reduced relapse and death without an increased incidence of graft-versus-host-disease after reduced intensity conditioning allogeneic hematopoietic stem cell transplantation. Measuring reconstituted natural killer cells expressing CD56(+)/CD16(+) post-transplant may have novel prognostic and therapeutic implications.

Recurrence of IgA Nephropathy after Kidney Transplantation in Adults

BACKGROUND AND OBJECTIVES

In patients with kidney failure due to IgA nephropathy, IgA deposits can recur in a subsequent kidney transplant. The incidence, effect, and risk factors of IgA nephropathy recurrence is unclear, because most studies have been single center and sample sizes are relatively small.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We performed a multicenter, international, retrospective study to determine the incidence, risk factors, and treatment response of recurrent IgA nephropathy after kidney transplantation. Data were collected from all consecutive patients with biopsy-proven IgA nephropathy transplanted between 2005 and 2015, across 16 "The Post-Transplant Glomerular Disease" study centers in Europe, North America, and South America.

RESULTS

Out of 504 transplant recipients with IgA nephropathy, recurrent IgA deposits were identified by kidney biopsy in 82 patients; cumulative incidence of recurrence was 23% at 15 years (95% confidence interval, 14 to 34). Multivariable Cox regression revealed a higher risk for recurrence of IgA deposits in patients with a pre-emptive kidney transplant (hazard ratio, 3.45; 95% confidence interval, 1.31 to 9.17) and in patients with preformed donor-specific antibodies (hazard ratio, 2.59; 95% confidence interval, 1.09 to 6.19). After kidney transplantation, development of de novo donor-specific antibodies was associated with subsequent higher risk of recurrence of IgA nephropathy (hazard ratio, 6.65; 95% confidence interval, 3.33 to 13.27). Immunosuppressive regimen was not associated with recurrent IgA nephropathy in multivariable analysis, including steroid use. Graft loss was higher in patients with recurrence of IgA nephropathy compared with patients without (hazard ratio, 3.69; 95% confidence interval, 2.04 to 6.66), resulting in 32% (95% confidence interval, 50 to 82) graft loss at 8 years after diagnosis of recurrence.

CONCLUSIONS

In our international cohort, cumulative risk of IgA nephropathy recurrence increased after transplant and was associated with a 3.7-fold greater risk of graft loss.

Significant Alterations in Reported Clinical Practice Associated with Increased Oversight of Organ Transplant Center Performance

In the past several years, emphasis on quality metrics in the field of organ transplantation has increased significantly, largely because of the new conditions of participation issued by the Centers for Medicare and Medicaid Services. These regulations directly associate patients' outcomes and measured performance of centers with the distribution of public funding to institutions. Moreover, insurers and marketing ventures have used publicly available outcomes data from transplant centers for business decision making and advertisement purposes. We gave a 10-question survey to attendees of the Transplant Management Forum at the 2009 meeting of the United Network for Organ Sharing to ascertain how centers have responded to the increased oversight of performance. Of 63 responses, 55% indicated a low or near low performance rating at their center in the past 3 years. Respondents from low-performing centers were significantly more likely to indicate increased selection criteria for candidates (81% vs 38%, P= .001) and donors (77% vs 31%, P< .001) as well as alterations in clinical protocols (84% vs 52%, P=.007). Among respondents indicating lost insurance contracts (31%), these differences were also highly significant. Based on respondents' perceptions, outcomes of performance evaluations are associated with significant changes in clinical practice at transplant centers. The transplant community and policy makers should practice vigilance that performance evaluations and regulatory oversight do not inadvertently lead to diminished access to care among viable candidates or decreased transplant volume.

A 10-year Analysis of Organ Donation after Cardiac Death in the United States

BACKGROUND

The greatest challenge facing transplantation today is how to increase the number of organ donors. Patients with severe brain injury who are not brain-dead can donate organs after they are removed from a ventilator and allowed to die, termed donation after cardiac death (DCD).

METHODS

We analyzed the database of all organs recovered from deceased donors in the United States from 1994 through 2003 to determine DCD trends in the United States. The database was obtained from the United Network for Organ Sharing (UNOS).

RESULTS

There were 57,681 deceased donors reported from 1994 through 2003. Of these, 1,177 were donors without a heartbeat (DWHB), 55,206 were brain dead donors, and 1,298 were unspecified donors. At least one organ was transplanted from 1010 of the 1177 DWHB. Organ procurement organizations (OPOs) reported 0-212 DWHB accounting for up to 12.3 percent of deceased donors. There was a steady annual increase in the number of DWHB, but in 2003 there were still 19 of 59 OPOs that recovered no DWHB. A total of 2,231 organs were transplanted from the 1,177 DWHB donors, and another 665 organs were recovered for transplantation but not transplanted. The transplanted organs included 1,779 kidneys, 395 livers, 54 pancreata, 2 lungs, and 1 heart. Organs from DWHB can be successfully transplanted.

CONCLUSIONS

Wider use of DWHB has the potential to greatly increase the number of organ transplants performed each year in the United States.

Prognostic importance of serum alkaline phosphatase in CKD stages 3-4 in a clinical population

BACKGROUND

Elevated total serum alkaline phosphatase (ALP) levels have been associated with mortality in the general population and in dialysis patients.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

28,678 patients with chronic kidney disease (CKD) stages 3 and 4 (estimated glomerular filtration rate, 15-59 mL/min/1.73 m(2)) were identified using the Cleveland Clinic CKD Registry. CKD was defined as 2 estimated glomerular filtration rate values <60 mL/min/1.73 m(2) drawn more than 90 days apart using the CKD-EPI (CKD Epidemiology Collaboration) creatinine equation.

PREDICTOR

ALP levels measured using the calorimetric assay were examined as quartiles (quartile [Q]1, <66 U/L; Q2, 66-81 U/L; Q3, 82-101 U/L; and Q4, ≥102 U/L) and as a continuous measure.

OUTCOMES & MEASUREMENTS

All-cause mortality and end-stage renal disease (ESRD) were ascertained using the Social Security Death Index and US Renal Data System.

RESULTS

After a median follow-up of 2.2 years, 588 patients progressed to ESRD and 4,755 died. There was a graded increase in risk of mortality with higher ALP quartiles (Q2, Q3, and Q4) compared to the reference quartile (Q1) after adjusting for demographics, comorbid conditions, use of relevant medications, and liver function test results. The highest ALP quartile was associated with an HR for ESRD of 1.38 (95% CI, 1.09-1.76). Each 1-SD (42.7 U/L) higher ALP level was associated with 15% (95% CI, 1.09-1.22) and 16% (95% CI, 1.14-1.18) increased risk of ESRD and mortality, respectively.

LIMITATIONS

Single-center observational study; lack of complete data, including parathyroid hormone level, for all study participants, and attrition bias.

CONCLUSIONS

Higher serum ALP levels in patients with CKD stages 3-4 were associated independently with all-cause mortality and ESRD.

The association of community health indicators with outcomes for kidney transplant recipients in the United States

OBJECTIVE

To evaluate the association of community health indicators with outcomes for kidney transplant recipients.

DESIGN

Retrospective observational cohort study using multivariable Cox proportional hazards models.

SETTING

Transplant recipients in the United States from the Scientific Registry of Transplant Recipients merged with health indicators compiled from several national databases and the Centers for Disease Control and Prevention, including the National Center for Health Statistics, the Behavioral Risk Factor Surveillance System, and the National Center for Chronic Disease Prevention and Health Promotion.

PATIENTS

A total of 100 164 living and deceased donor adult (aged 18 years) kidney transplant recipients who underwent a transplant between January 1, 2004, and December 31, 2010.

MAIN OUTCOME MEASURES

Risk-adjusted time to posttransplant mortality and graft loss.

RESULTS

Multiple health indicators from recipients' residence were independently associated with outcomes, including low birth weight, preventable hospitalizations, inactivity rate, and smoking and obesity prevalence. Recipients in the highest-risk counties were more likely to be African American (adjusted odds ratio, 1.59, 95% CI, 1.51-1.68), to be younger (aged 18-39 years; 1.46; 1.32-1.60), to have lower educational attainment (<high school; 1.84; 1.62-2.08), and to have public insurance (1.46; 1.38-1.54). Proportions of recipients from higher-risk counties varied dramatically by center and region. There was an independent graded effect between health indicators and posttransplant mortality, including notable hazard associated with the highest-risk counties (adjusted hazard ratio, 1.26; 95% CI, 1.13-1.40).

CONCLUSIONS

In a national cohort of patients undergoing complex medical procedures, health indicators from patients' communities are strong independent predictors of all-cause mortality. Findings highlight the importance of community conditions for risk stratification of patients and development of individualized treatment protocols. Findings also demonstrate that standard risk adjustment does not capture important factors that may affect unbiased performance evaluations of transplant centers.

Adiposity measures, lean body mass, physical activity and mortality: NHANES 1999-2004

Background

Obesity and physical inactivity are major public health problems. We studied the associations between measures of adiposity, lean body mass, leisure time physical activity (LTPA), and death in those with and without chronic kidney disease (CKD).

Methods

Associations between body mass index (BMI), waist circumference (WC), percent body fat, lean body mass (assessed with Dual-Energy X-ray Absorptiometry[DEXA]), leisure time physical activity (LTPA) and death were examined using the National Health and Nutrition Examination Surveys (NHANES 1999–2004). All-cause mortality was ascertained by linkage of NHANES files with the National Death Index.

Results

9,433 non-CKD participants and 2,153 CKD participants who had fat mass measured using DEXA, BMI, WC, LTPA and mortality data were included. After adjusting for demographics, comorbid conditions, kidney function measures, C-Reactive Protein (CRP), and sodium intake there was no significant risk for death noted with higher WC, fat mass and BMI in those with and without CKD. When examining normal, overweight, and obese groups based on BMI criteria, being overweight (BMI 25–29.9 kg/m²) was associated with lower risk of death in those without CKD (Hazard ratio 0.62, 95% CI 0.40, 0.95). Higher lean body mass was associated with lower risk for death in those without kidney disease but not in the CKD population. There was a significantly higher risk for death among those who did not meet the minimum LTPA goals compared to those who met or exceeded the recommended activity levels (>450 MET/min/week) in those with and without CKD (CKD Hazard ratio: 1.36, 95% CI 1.003, 1.85; non-CKD HR 1.65, 95% CI 1.21, 2.26).

Conclusions

In a representative sample of the US population, higher LTPA levels and lean body mass were associated with lower mortality in those without kidney disease. In CKD, higher LTPA was associated with lower risk of death. There was no association between adiposity measures and death in those with and without CKD except for lower mortality associated with overweight among those without CKD. The data suggests the need to develop programs to facilitate an increase in physical activity in people with and without kidney disease.

Presence and outcomes of kidney disease in patients with pulmonary hypertension

BACKGROUND AND OBJECTIVES

Pulmonary hypertension is associated with higher mortality rates. The associations of nondialysis-dependent CKD and all-cause mortality in patients with pulmonary hypertension were studied.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The study population included those patients who underwent right heart catheterization for confirmation of pulmonary hypertension between 1996 and January 2011. Pulmonary hypertension was defined as the presence of mean pulmonary artery pressure ≥ 25 mmHg at rest measured by right heart catheterization. CKD was defined as the presence of two measurements of eGFR<60 ml/min per 1.73 m(2) 90 days apart. The risk factors associated with CKD as well as the association between CKD and death in those patients with pulmonary hypertension using logistic regression and Cox proportional hazard models were examined.

RESULTS

Of 1088 patients with pulmonary hypertension, 388 (36%) patients had CKD: 340 patients had stage 3 CKD, and 48 (4%) patients had stage 4 CKD. In the multivariable analysis, older age, higher hemoglobin, and higher mean right atrial pressures were independently associated with CKD. During a median follow-up of 3.2 years (interquartile range=1.5-5.6 years), 559 patients died. After adjusting for relevant covariates, presence of stage 3 CKD (hazard ratio, 1.37; 95% confidence interval, 1.14 to 1.66) and stage 4 CKD (hazard ratio, 2.69; 95% confidence interval, 1.88 to 3.86) was associated with all-cause mortality in those patients with pulmonary hypertension. When eGFR was examined as a continuous measure, a 5 ml/min per 1.73 m(2) lower eGFR was associated with a 5% (95% confidence interval, 1.03 to 1.07) higher hazard for death. This higher risk with CKD was similar irrespective of demographics, left ventricular function, and pulmonary capillary wedge pressure.

CONCLUSION

In a clinical population referred for right heart catheterization, presence of CKD was associated with higher all-cause mortality in those patients with pulmonary hypertension. Mechanisms that may underlie these associations warrant additional studies.

Critical Factors Associated With Missing Follow-Up Data for Living Kidney Donors in the United States

Follow-up care for living kidney donors is an important responsibility of the transplant community. Prior reports indicate incomplete donor follow-up information, which may reflect both donor and transplant center factors. New UNOS regulations require reporting of donor follow-up information by centers for 2 years. We utilized national SRTR data to evaluate donor and center-level factors associated with completed follow-up for donors 2008-2012 (n = 30 026) using multivariable hierarchical logistic models. We compared center follow-up compliance based on current UNOS standards using adjusted and unadjusted models. Complete follow-up at 6, 12, and 24 months was 67%, 60%, and 50% for clinical and 51%, 40%, and 30% for laboratory data, respectively, but have improved over time. Donor risk factors for missing laboratory data included younger age 18-34 (adjusted odds ratio [AOR] = 2.03, 1.58-2.60), black race (AOR = 1.17, 1.05-1.30), lack of insurance (AOR = 1.25, 1.15-1.36), lower educational attainment (AOR = 1.19, 1.06-1.34), >500 miles to center (AOR = 1.78, 1.60-1.98), and centers performing >40 living donor transplants/year (AOR = 2.20, 1.21-3.98). Risk-adjustment moderately shifted classification of center compliance with UNOS standards. There is substantial missing donor follow-up with marked variation by donor characteristics and centers. Although follow-up has improved over time, targeted efforts are needed for donors with selected characteristics and at centers with higher living donor volume. Adding adjustment for donor factors to policies regulating follow-up may function to provide more balanced evaluation of center efforts.

Fructose increases risk for kidney stones: potential role in metabolic syndrome and heat stress

Background

Fructose intake, mainly as table sugar or high fructose corn syrup, has increased in recent decades and is associated with increased risk for kidney stones. We hypothesized that fructose intake alters serum and urinary components involved in stone formation.

Methods

We analyzed a previously published randomized controlled study that included 33 healthy male adults (40–65 years of age) who ingested 200 g of fructose (supplied in a 2-L volume of 10% fructose in water) daily for 2 weeks. Participants were evaluated at the Unit of Nephrology of the Mateo Orfila Hospital in Menorca. Changes in serum levels of magnesium, calcium, uric acid, phosphorus, vitamin D, and intact PTH levels were evaluated. Urine magnesium, calcium, uric acid, phosphorus, citrate, oxalate, sodium, potassium, as well as urinary pH, were measured.

Results

Ingestion of fructose was associated with an increased serum level of uric acid (p < 0.001), a decrease in serum ionized calcium (p = 0.003) with a mild increase in PTH (p < 0.05) and a drop in urinary pH (p = 0.02), an increase in urine oxalate (p = 0.016) and decrease in urinary magnesium (p = 0.003).

Conclusions

Fructose appears to increase urinary stone formation in part via effects on urate metabolism and urinary pH, and also via effects on oxalate. Fructose may be a contributing factor for the development of kidney stones in subjects with metabolic syndrome and those suffering from heat stress.

Trial registration

ClinicalTrials.gov NCT00639756 March 20, 2008.

Interleukin 12 Is Associated with Reduced Relapse without Increased Incidence of Graft-versus-Host Disease after Allogeneic Hematopoietic Stem Cell Transplantation

Interleukin (IL)-12 has antitumor effects in murine studies. To evaluate this clinically, we investigated whether high levels of circulating IL-12 in patients after allogeneic hematopoietic stem cell transplantation (HSCT) are associated with improved relapse-free survival. We prospectively studied 134 patients undergoing HSCT. Median follow-up was 1158 days (range, 70-1792 days). Plasma IL-12 levels were measured before transplantation and on days 0, +4, +7, and +14 after transplantation. The highest levels were seen on days +4 and +7 and were categorized by a cluster analysis of the logarithmically transformed IL-12 concentrations, which were then correlated with relapse-free survival. Forty-six patients had low levels of IL-12 (median, 2 pg/mL; range, 0-6.5 pg/mL), 49 patients had medium levels (median, 20.5 pg/mL; range, 7-75.5 pg/mL), and 25 patients had high levels (median, 181 pg/mL; range, 84-623 pg/mL). Patients with high IL-12 levels before transplantation had the highest increase after transplantation. With a multivariate Cox model for relapse onset, with the low IL-12 level as the reference, patients in the high-IL-12 group had an adjusted hazard ratio of 0.27 (95% confidence interval, 0.09-0.79), and medium group patients had a hazard ratio of 0.65 (95% confidence interval, 0.31-1.36). The incidences of relapse at 500 days by Kaplan-Meier analysis by IL-12 group were 23.0% (high group), 40.3% (medium group), and 48.8% (low group). There was no association between IL-12 levels and the risk of acute graft-versus-host disease (GVHD; P = .51) or chronic GVHD (P = .28). In conclusion, high IL-12 levels after HSCT are associated with improved relapse-free survival without increasing the risk for GVHD. Patients with high pretransplantation IL-12 levels have an increased likelihood of higher posttransplantation IL-12 levels, possibly because of a host-graft interaction, and this may predispose to better clinical outcomes.