September 2017: Abstract Roundup

ACUTE KIDNEY INJURY

Diagnoses Associated with Hospital-Acquired AKI
Clinical Journal of the American Society of Nephrology. 2017;12(6):874-884

Researchers in France conducted a retrospective analysis of the association between hospital-acquired acute kidney injury (AKI) and each International Classification of Diseases-Tenth Revision (ICD-10) category to identify the diagnoses associated with AKI. The analysis included data on hospital stays for 126,736 unique individuals. The analysis was performed by Anne-Sophie Jannot, MD, PhD, et al.

The primary factors associated with hospital-acquired AKI are hemodynamic impairment and surgical procedures, and five clusters of diagnoses were revealed: sepsis, heart diseases, polytrauma, liver disease, and cardiovascular surgery. The ICD-10 code corresponding to AKI was recorded in 30% of the cases with hospital-acquired AKI identified, and in those cases, 20% of the diagnoses associated with hospital-acquired AKI corresponded to kidney disease (tubulointerstitial nephritis, necrotizing vasculitis, or myeloma cast nephrology).

“Our approach, derived from phenome-wide association studies, is a valuable way to comprehensively identify and classify all of the diagnoses and clusters of diagnosis associated with hospital-acquired AKI. Our analysis delivers insights into how diagnoses associated with hospital-acquired AKI evolved over time. On the basis of ICD-10 codes, hospital-acquired AKI appears largely underestimated in this academic hospital,” the researchers said.

CHRONIC KIDNEY DISEASE

Estimating Decline in Kidney Function with Anthropometric Measures of Body Fat 
Clinical Journal of the American Society of Nephrology. 2017;12(6):896-903

Researchers, led by Magdalena Madero, MD, conducted the Health Aging and Body Composition Study designed to compare the association of computed tomography (CT) and anthropometric measures of obesity with kidney outcomes. CT measures included visceral abdominal fat (VAT), subcutaneous adipose tissue (SAT), and intermuscular fat area (IMAT); anthropometric measures included waist circumference (WC) and body mass index (BMI).

The study included 2483 participants; mean age was 74 years, 49% were men, 39% were black, 59% were hypertensive, and 15% were diabetic. Seventeen percent of the study population experienced decline in kidney function; incident chronic kidney disease also occurred in 17% of those at risk. There were associations between decline in kidney function and SAT, VAT, IMAT, BMI, and WC in continuous models. There was a significant association between VAT and CKD with regard to decline in kidney function (P=.01).

In conclusion, the researchers said, “Anthropometric measures of body fat appear to provide as consistent estimates of kidney function decline risk as CT measures in elders.”

Possible Biomarker for Risk of CKD Progression: Growth Differentiation Factor-15
Journal of the American Society of Nephrology. 2017;28(7):2233-2240

Among patients with chronic kidney disease (CKD), elevations in growth differentiation factor-15 (GDF-15) may identify a novel pathway involved in loss of kidney function, according to Viji Nair, PhD, and colleagues. The researchers utilized data from participants in the Clinical Phenotyping and Resource Biobank (C-PROBE) study (n=224) and the Seattle Kidney Study (SKS) (n=297) to test whether there is a correlation between kidney tissue expression of GDF15 mRNA and circulating levels of GFD-15. They also sought to determine whether there is an association between elevations in circulating GFD-15 and decline in kidney function.

Seventy-two (32.1%) of the C-Probe participants and 94 (3.0%) of the SKS participants reached a composite end point of 30% decline in estimated glomerular filtration rate or progression to end-stage renal disease over a median of 1.0 and 2.0 years of follow up, respectively. Following adjustment for potential confounders, there was an association between every doubling of GFD-15 level and a 72% higher and 65% higher risk of progression of kidney disease in C-PROBE and SKS participants, respectively.

“These results show that circulating GDF-15 levels strongly correlated with intrarenal expression of GFD-15 and significantly associated with increased risk of CKD progression in two independent cohorts. Circulating GDF-15 may be a marker for intrarenal GDF-15-related signaling pathways associated with CKD and CKD progression,” the researchers said.

Using Rescaled Renal Biomarkers to Diagnose Impaired Renal Function
Clinica Chimica Acta. 2017;471:164-170

Equations to estimate glomerular filtration rate (GFR) rely on serum creatinine, a major contributing value in those calculations; equations based on serum cystatin C have also been developed. Hans Pottel, PhD, and colleagues recently conducted a study to examine the relationship between rescaled levels of those renal biomarkers and measured GFR (mGFR).

The study assessed the diagnostic ability of rescaled serum creatinine and rescaled serum cystatin C levels to detect impaired kidney function in 8584 participants from 12 cohorts with measured GFR. The researchers calculated sensitivity and specificity of the rescaled biomarkers to identify kidney disease with reference to a fixed (60 mL/min/1.73 m2) as well as an age-dependent threshold for mGFR.

Results of the study demonstrated that there is a close relationship between the upper reference limit of 1.33 for rescaled renal biomarkers and the age-dependent threshold for defining kidney status by mGFR. Sensitivity and specificity for the rescaled biomarkers is nearly 90% for all ages. Specificity in children and sensitivity in older adults were observed when the fixed threshold of 60 mL/min/1.73 m2 for mGFR was used.

In conclusion, the researchers said, “Impaired kidney function can be diagnosed by rescaled biomarkers instead of eGFR equations using the fixed threshold of 1.33 for all ages, consistent with an age-dependent threshold of mGFR.”

DIALYSIS

2014 Data from the National Healthcare Safety Network Dialysis Event Surveillance
Clinical Journal of the American Society of Nephrology. 2017;12(7):1139-1146

The US Centers for Disease Control and Prevention conducts surveillance to track bloodstream and vascular access infections among people receiving outpatient hemodialysis. Duc B. Nguyen, MD, and colleagues summarized 2014 data submitted to the National Healthcare Safety Network Dialysis Event Surveillance in a report in the Clinical Journal of the American Society of Nephrology. There are three types of events reported by dialysis facilities: (1) bloodstream infections; (2) intravenous antimicrobial starts; and (3) pus, redness, or increased swelling at the hemodialysis vascular access site.

The network received dialysis event data in 2014 from 6005 outpatient dialysis facilities. A total of 160,971 events were reported, including bloodstream infections (n=29,516); intravenous antimicrobial starts (n=149,722;) and pus, redness, or increased swelling at the site of hemodialysis vascular access (n=38,310). Of the 29,516 bloodstream infections, 76.5% (n=22,576) were considered related to vascular access. Most of the bloodstream infections (63.0%) and access-related bloodstream infections (69.8%) occurred in patients with a central venous catheter.

In summary, the researchers said, “The 2014 National Healthcare Safety Network Dialysis Event data represent nearly all United States outpatient dialysis facilities. Rates of infection and other dialysis events were highest among patients with a central venous catheter compared with other vascular access data. Surveillance data can help define the epidemiology of important infections in this patient population.”

Changes in Frailty Over Time in Patients on Hemodialysis
Clinical Journal of the American Society of Nephrology. 2017;12(7):1100-1108

Patients receiving hemodialysis often experience frailty, leading to adverse outcomes. There are few data relating to changes in frailty over time and the factors associated with those changes. Kirsten L. Johansen, MD, and colleagues conducted an analysis of data from an end-stage renal disease cohort study; study participants had frailty assessments at baseline, and at 12 and 24 months. The distribution of frailty scores was similar at each evaluation. Most scores changed, with patients improving as often as worsening. There were associations between higher frailty scores and Hispanic ethnicity and diabetes; there was an association between higher serum albumin and lower frailty scores. Patients whose serum albumin increased over time were less likely to become frail.

In conclusion, the researchers said, “There was substantial year to year variability in frailty scores, with approximately equal numbers of patients improving and worsening. Markers of inflammation and hospitalization were independently associated with worsening frailty. Studies should examine whether interventions to address inflammation or posthospitalization rehabilitation can improve the trajectory of frailty.”

GERIATRIC NEPHROLOGY

Palliative Care Consultations for Patients with Renal Disease versus Other Illnesses
Clinical Journal of the American Society of Nephrology. 2017;12(7):1085-1089

According to Vanessa Grubbs, MD, MPH, and colleagues, patients with end-stage renal disease receive palliative care less often that patients with other serious illnesses. Dr. Grubb et al. conducted an observational study designed to compare characteristics and outcomes of hospitalized patients in the United States who had a palliative care consultation for renal disease versus other serious illnesses.

Of 33,183 patients in a database collected by the Palliative Care Quality Network on patients who had a palliative care consultation, the researchers identified 1057 patients who had renal disease as the primary reason for the consultation. Mean age for those with renal disease was 71.9 years versus 72.8 years for patients with other serious illnesses.

At the time of the consultation, both groups of patients had similarly low mean Palliative Performance Scale scores and reported similar levels of anxiety (moderate to severe). With the exception of anxiety, the symptoms improved similarly following consultation regardless of diagnosis. Although change in code status was also similar between the two groups, fewer patients in the renal disease group were referred to hospice compared with patients with other serious illnesses (30.7% vs 37.6%, respectively; P<.001).

In summary, the researchers said, “Hospitalized patients with renal disease referred for palliative care consultation had similar palliative care needs, improved symptom management, and clarification of care as those with other serious illnesses.”

TRANSPLANTATION

Alemtuzumab Prior to Kidney Transplantation in Pediatric Patients
Pediatric Transplantation. doi: 10.1111/petr.12941

A recent single-center, retrospective review was conducted by Michael M. Kaabak, MD, and colleagues to test the hypothesis that administration of alemtuzumab several weeks prior to kidney transplantation in pediatric patients (7 months-18 years of age) could eradicate peripheral lymphatic cells and promote donor-specific acceptance. The patients received a kidney transplant between September 2006 and April 2010.

Immunosuppression protocol included two 30 mg doses of alemtuzumab: one given 12 to 29 days before transplantation and one at the time of transplantation. Maintenance immunosuppression was based on a combination of low-dose calcineurin inhibitor and mycophenolate, with steroids tapered over the first 5 days post-transplantation. Follow-up continued for 7.8 years, and protocol biopsies were taken at 1 month, and 1, 3, and 5 years following transplantation.

Kaplan-Meier 8-year patient and graft survival rates in the patients treated with cyclosporine were 82.0 and 71.6, respectively; in patients treated with tacrolimus, 8-year patient and survival rates were 97.2 and 83.8, respectively. Thirty-five percent of patients treated with cyclosporine developed biopsy-proven acute rejection, compared with 8% of those treated with tacrolimus.

In conclusion, the researchers said, “Alemtuzumab pretreatment prior to living related donor kidney transplantation, followed by maintenance immunosuppression with tacrolimus and mycophenolate mofetil, is associated with reasonable long-term results in pediatric patients.”

Comparison of Outcomes between Antibody Induction Therapies after Transplantation
Journal of the American Society of Nephrology. 2017;28(7):2188-2200

Recipients of kidney transplantation often receive antibody induction. Neel Koyawala and colleagues utilized data from the Procurement and Transplantation Network linked with Medicare claims to compare outcomes between three induction therapies for kidney transplant recipients. The primary outcomes of interest were death and death or allograft failure. Secondary outcomes included death or sepsis, death or lymphoma, death or melanoma, and healthcare resource utilization within 1 year.

The researchers generated 1:1 pairs of alemtuzumab-rabbit antihymocyte globulin (rATG) (n=5330 pairs) and basiliximab-rATG (n=9378 pairs) recipients. Compared with rATG recipients, alemtuzumab recipients had higher risk of death and death or allograft failure (hazard ratio [HR], 1.14; 95% confidence interval [CI], 1.03-1.26; P<.01) and death or allograft failure (HR, 1.18; 95% CI, 1.09-1.28; P<.001). Compared with rATG recipients, basiliximab recipients had higher risk of death (HR, 1.08; 95% CI, 1.01-1.16; P=.03) and death or lymphoma (HR, 1.12; 95% CI, 1.01-1.23; P=.03).

“This observational evidence indicates that, compared with alemtuzumab and basiliximab, rATG associates with lower risk of adverse outcomes, including mortality,” the researchers said.