Prostate Advanced Radiation Technologies Investigating Quality of Life (PARTIQoL): A Phase III Randomized Clinical Trial of Proton Therapy vs. IMRT for Low or Intermediate Risk Prostate Cancer

PURPOSE/OBJECTIVE(S)

Prostate cancer is the most common non-cutaneous cancer diagnosed among men in the United States, and the majority of patients are diagnosed with localized disease. Men with localized prostate cancer have several treatment options including external beam radiotherapy with either photons or protons. Proton beam therapy (PBT) has certain dosimetric advantages and the potential to reduce treatment-associated morbidity and improve oncologic outcomes, but current PBT is significantly more costly than intensity-modulated radiotherapy (IMRT). The PARTIQoL trial (NCT01617161) is the first multicenter phase 3 randomized trial comparing protons to photons in the treatment of localized prostate cancer.

MATERIALS/METHODS

Patients with low or intermediate risk prostate cancer (Stage T1c-T2c, PSA < 20, Gleason score ≤ 7) are randomized to receive either PBT or IMRT, with targeted recruitment efforts for minority populations. A companion registry study has concurrently enrolled patients who declined randomization or whose insurance denied coverage for PBT. Patients are stratified by clinical site, age, use of rectal spacer, and fractionation schedule (conventional fractionation: 79.2 Gy in 44 fractions vs moderate hypofractionation: 70.0 Gy in 28 fractions). Participants are followed longitudinally to assess patient-reported outcomes (PROs) of bowel, urinary, and erectile function for 60 months after completion of radiotherapy (with an option for additional follow up through 10 years). Participants may also participate in correlative studies, including serial CT imaging during treatment and analyses of biopsy tissue, blood and urine specimens. The primary objective is to compare PROs of bowel function using the EPIC score at 24 months following completion of radiation. Secondary objectives are to assess treatment-related differences in urinary and erectile functions, adverse events, efficacy endpoints (biochemical control, metastasis-free survival, disease-specific survival, and overall survival), health state utilities, perceptions of care, late effects, cost-effectiveness, association between radiotherapy dose distribution and PROs, and to identify biomarkers of radiation response and toxicity.

RESULTS

The randomized trial has completed accrual, with 450 patients enrolled at 27 sites between June 2012 and November 2021. 20.3% of patients enrolled are non-white. Accrual on the companion registry is active, with 354 patients enrolled as of February 2023.

CONCLUSION

Follow-up for the primary endpoint on the randomized trial will be reached in 2024. The PARTIQoL randomized clinical trial will rigorously assess the clinical benefits of PBT relative to IMRT and results will inform decision making by patients, providers, policymakers, and payers.

5-Year Renal Function Outcomes after SABR for Primary Renal Cell Carcinoma: A Report from the International Radiosurgery Oncology Consortium of the Kidney (IROCK)

PURPOSE/OBJECTIVE(S)

Renal cell carcinoma (RCC) presents uncommonly in patients with a congenital solitary kidney or prior contralateral nephrectomy. The objective of this study was to compare renal function outcomes of stereotactic ablative body radiotherapy (SABR) in patients with solitary vs. bilateral kidneys.

MATERIALS/METHODS

Patients with primary RCC with ≥2 years of follow-up at 12 participating International Radiosurgery Consortium for Kidney (IROCK) institutions were included. Patients with upper tract urothelial carcinoma or metastatic disease were excluded. Renal function was measured by estimated glomerular filtration rate (eGFR). For patients where eGFR was not recorded, Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation was used to estimate eGFR based on known creatinine. Baseline characteristics and renal function outcomes were compared between solitary vs. bilateral kidneys. Multivariable logistic regression was used to identify factors predictive of eGFR decline ≥ 15 mL/min and any eGFR increase evaluated at 1-year post-SABR.

RESULTS

One hundred and ninety patients with solitary (n = 56) or bilateral kidneys (n = 134) underwent SABR and were followed for a median of 5.0 years (IQR: 3.4-6.8). Pre-SABR eGFR (mean ± SD) was similar in patients with solitary (61.1 ± 23.2 mL/min) vs. bilateral kidneys (58.0 ± 22.3 mL/min, p = 0.324). Mean tumor size was 3.70 ± 1.40 cm in solitary and 4.35 ± 2.50 cm in bilateral kidneys (p = 0.026). After SABR, an initial compensatory increase in eGFR was observed in both cohorts (22.7% solitary and 17.7% bilateral at 1 year). This compensatory increase persisted in patients with bilateral but not a solitary kidney (10.3% vs. 0% at 3-years and 21.1% vs. 0% at 5-years, respectively). At 5-years post-SABR, eGFR decreased by -14.5 ± 7.6 in solitary and -13.3 ± 15.9 mL/min in bilateral kidneys (p = 0.665). At all timepoints assessed, there were no significant differences in eGFR decline between solitary vs. bilateral cohorts (all p > 0.05). There were also no significant differences in post-SABR end-stage renal disease (7.1% vs. 6.7%) or dialysis (3.6% vs. 3.7%) in solitary vs. bilateral, respectively. Multivariable analysis demonstrated that increasing tumor size (OR per 1 cm: 1.57; 95% CI: 1.14-2.16, p = 0.006) and baseline eGFR (OR per 10 mL/min: 1.30; 95% CI: 1.02-1.66, p = 0.034) was more likely to be associated with eGFR decline ≥ 15 mL/min. There was no significant association between solitary vs. bilateral kidney and eGFR decline (OR: 1.22; 95% CI: 0.45-3.34, p = 0.693).

CONCLUSION

There was no observed difference between renal function outcomes in patients with a solitary vs. bilateral kidneys. While larger tumor size may increase the risk of eGFR decline post-SABR, treatment of a solitary kidney does not appear to increase the risk of renal dysfunction long-term.

Management and analysis of high-throughput sequence data for infectious animal diseases

Advances in technology and decreasing costs have accelerated the use of high-throughput sequencing (HTS) for both diagnosis and characterisation of infectious animal diseases. High-throughput sequencing offers several advantages over previous techniques, including rapid turnaround times and the ability to resolve single nucleotide changes among samples, both of which are important for epidemiological investigations of outbreaks. However, due to the plethora of genetic data being routinely generated, the storage and analysis of these data are proving challenging in their own right. In this article, the authors provide insight into the aspects of data management and analysis that should be considered before adopting HTS for routine animal health diagnostics. These elements fall largely into three interrelated categories: data storage, data analysis and quality assurance. Each has numerous complexities and may need to be adapted as HTS evolves. Making appropriate strategic decisions about bioinformatic sequence analysis early on in project development will help to avert major issues in the long term.

Relationship between cortical and medullary thickness and glomerular filtration rate among living kidney donors

The relationship between the kidney cortex and medulla is not well understood in healthy populations. This study characterised the relationship between cortical/medullary thickness and measured glomerular filtration rate (GFR) in 390 living kidney donors. A positive relationship was observed between medullary, but not cortical, thickness and GFR. We propose that this reflects a correlation between juxtamedullary nephron number and GFR.

PKR-like ER kinase (PERK) Haplotypes Are Associated with Depressive Symptoms in People with HIV

Background

Depression is a debilitating and difficult-to-treat condition in people with HIV (PWH) despite viral suppression on antiretroviral therapy (ART). Depression is associated with activation of the PKR-like ER kinase (PERK) pathway, which regulates protein synthesis in response to metabolic stress. We evaluated common PERK haplotypes that influence PERK expression in relation to depressed mood in PWH.

Methods

PWH from 6 research centers were enrolled in the study. Genotyping was conducted using targeted sequencing with TaqMan. The major PERK haplotypes A, B, and D were identified. Depressive symptom severity was assessed using the Beck Depression Inventory-II (BDI-II). Covariates including genetically-defined ancestry, demographics, HIV disease/treatment parameters and antidepressant treatments were assessed. Data were analyzed using multivariable regression models.

Results

A total of 287 PWH with a mean (SD) age of 57.1±7.8 years were enrolled. Although the largest ethnic group was non-Hispanic white (n=129, 45.3%), African-American (n=124, 43.5%) and Hispanic (n=30, 10.5%) made up over half the sample. 20.3% were female and 96.5% were virally suppressed. Mean BDI-II was 9.6±9.5, and 28.9% scored above the cutoff for mild depression (BDI-II>13). PERK haplotype frequencies were AA57.8%, AB25.8%, AD 10.1%, and BB4.88%. PERK haplotypes were differentially represented according to genetic ancestry (p=6.84e-6). BDI-II scores were significantly higher in participants with the AB haplotype (F=4.45, p=0.0007).This finding was robust to consideration of potential confounds.

Conclusion

PERK haplotypes were associated with depressed mood in PWH.Consequently, pharmacological targeting of PERK-related pathways might amelioratedepression in PWH.

Factors associated with hospitalisations and deaths of residential aged care residents with COVID-19 during the Omicron (BA.1) wave in Queensland

OBJECTIVE

To identify characteristics associated with the hospitalisation and death of people with COVID-19 living in residential aged care facilities (RACFs).

DESIGN

Retrospective cohort study.

SETTING, PARTICIPANTS

All confirmed (polymerase chain reaction testing) or probable SARS-CoV-2 infections (rapid antigen tests) in residents of the 86 RACFs in the Metro South Hospital and Health Service area (southeast Queensland), 13 December 2021 - 24 January 2022.

MAIN OUTCOME MEASURES

Hospitalisation within 14 days or death within 28 days of COVID-19 diagnosis.

RESULTS

Of 1071 RACF residents with COVID-19, 151 were hospitalised within 14 days and 126 died within 28 days of diagnosis. Likelihood of death increased with age (per five years: adjusted odds ratio [aOR], 1.38; 95% confidence interval [CI], 1.21-1.57), but not that of hospitalisation. Men were more likely to be hospitalised (aOR, 1.7; 95% CI, 1.2-2.4) or die (aOR, 2.5; 95% CI, 1.7-3.6) than women. The likelihood of hospitalisation was greater for those with dementia (aOR, 1.9; 95% CI, 1.2-3.0), heart failure (aOR, 1.7; 95% CI, 1.1-2.7), chronic kidney disease (aOR, 1.7; 95% CI, 1.1-2.5), or asthma (aOR, 2.2; 95% CI, 1.2-3.8). The likelihood of death was greater for residents with dementia (aOR, 2.2; 95% CI, 1.3-3.7), diabetes mellitus (aOR, 1.9; 95% CI, 1.3-3.0), heart failure (aOR, 2.0; 95% CI, 1.1-3.3), or chronic lung disease (aOR, 1.7; 95% CI, 1.1-2.7). The likelihood of hospitalisation and death were each higher for residents who had received two or fewer vaccine doses than for those who had received three doses.

CONCLUSIONS

Most characteristics that influenced the likelihood of hospitalisation or death of RACF residents with COVID-19 were non-modifiable factors linked with frailty and general health status. Having received three COVID-19 vaccine doses was associated with much lower likelihood of hospitalisation or death.

Combination Dabrafenib and Trametinib Versus Combination Nivolumab and Ipilimumab for Patients With Advanced BRAF-Mutant Melanoma: The DREAMseq Trial-ECOG-ACRIN EA6134

PURPOSE

Combination programmed cell death protein 1/cytotoxic T-cell lymphocyte-4-blockade and dual BRAF/MEK inhibition have each shown significant clinical benefit in patients with BRAFV600-mutant metastatic melanoma, leading to broad regulatory approval. Little prospective data exist to guide the choice of either initial therapy or treatment sequence in this population. This study was conducted to determine which initial treatment or treatment sequence produced the best efficacy.

PATIENTS AND METHODS

In a phase III trial, patients with treatment-naive BRAFV600-mutant metastatic melanoma were randomly assigned to receive either combination nivolumab/ipilimumab (arm A) or dabrafenib/trametinib (arm B) in step 1, and at disease progression were enrolled in step 2 to receive the alternate therapy, dabrafenib/trametinib (arm C) or nivolumab/ipilimumab (arm D). The primary end point was 2-year overall survival (OS). Secondary end points were 3-year OS, objective response rate, response duration, progression-free survival, crossover feasibility, and safety.

RESULTS

A total of 265 patients were enrolled, with 73 going onto step 2 (27 in arm C and 46 in arm D). The study was stopped early by the independent Data Safety Monitoring Committee because of a clinically significant end point being achieved. The 2-year OS for those starting on arm A was 71.8% (95% CI, 62.5 to 79.1) and arm B 51.5% (95% CI, 41.7 to 60.4; log-rank P = .010). Step 1 progression-free survival favored arm A (P = .054). Objective response rates were arm A: 46.0%; arm B: 43.0%; arm C: 47.8%; and arm D: 29.6%. Median duration of response was not reached for arm A and 12.7 months for arm B (P < .001). Crossover occurred in 52% of patients with documented disease progression. Grade ≥ 3 toxicities occurred with similar frequency between arms, and regimen toxicity profiles were as anticipated.

CONCLUSION

Combination nivolumab/ipilimumab followed by BRAF and MEK inhibitor therapy, if necessary, should be the preferred treatment sequence for a large majority of patients.

Two-dimensional correlated spectroscopy distinguishes clear cell renal cell carcinoma from other kidney neoplasms and non-cancer kidney

Background

Routinely used clinical scanners, such as computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound (US), are unable to distinguish between aggressive and indolent tumor subtypes in masses localized to the kidney, often leading to surgical overtreatment. The results of the current investigation demonstrate that chemical differences, detected in human kidney biopsies using two-dimensional COrrelated SpectroscopY (2D L-COSY) and evaluated using multivariate statistical analysis, can distinguish these subtypes.

Methods

One hundred and twenty-six biopsy samples from patients with a confirmed enhancing kidney mass on abdominal imaging were analyzed as part of the training set. A further forty-three samples were used for model validation. In patients undergoing radical nephrectomy, biopsies of non-cancer kidney cortical tissue were also collected as a non-cancer control group. Spectroscopy data were analyzed using multivariate statistical analysis, including principal component analysis (PCA) and orthogonal projection to latent structures with discriminant analysis (OPLS-DA), to identify biomarkers in kidney cancer tissue that was also classified using the gold-standard of histopathology.

Results

The data analysis methodology showed good separation between clear cell renal cell carcinoma (ccRCC) versus non-clear cell RCC (non-ccRCC) and non-cancer cortical tissue from the kidneys of tumor-bearing patients. Variable Importance for the Projection (VIP) values, and OPLS-DA loadings plots were used to identify chemical species that correlated significantly with the histopathological classification. Model validation resulted in the correct classification of 37/43 biopsy samples, which included the correct classification of 15/17 ccRCC biopsies, achieving an overall predictive accuracy of 86%, Those chemical markers with a VIP value >1.2 were further analyzed using univariate statistical analysis. A subgroup analysis of 47 tumor tissues arising from T1 tumors revealed distinct separation between ccRCC and non-ccRCC tissues.

Conclusions

This study provides metabolic insights that could have future diagnostic and/or clinical value. The results of this work demonstrate a clear separation between clear cell and non-ccRCC and non-cancer kidney tissue from tumor-bearing patients. The clinical translation of these results will now require the development of a one-dimensional (1D) magnetic resonance spectroscopy (MRS) protocol, for the kidney, using an in vivo clinical MRI scanner.

Kidney failure, CKD progression and mortality after nephrectomy

Purpose

This study tested the hypothesis that progression of chronic kidney disease (CKD) is less aggressive in patients whose primary cause of CKD was nephrectomy, compared with non-surgical causes.

Methods

A sample of 5983 patients from five specialist nephrology practices was ascertained from the Queensland CKD Registry. Rates of kidney failure/death were compared on primary aetiology of CKD using multivariable Cox proportional hazards models. CKD progression was compared using multivariable linear and logistic regression analyses.

Results

Of 235 patients with an acquired single kidney as their primary cause of CKD, 24 (10%) and 38 (17%) developed kidney failure or died at median [IQR] follow-up times of 12.9 [2.5–31.0] and 33.6 [18.0–57.9] months after recruitment. Among patients with an eGFR < 45 mL/min per 1.73m² at recruitment, patients with diabetic nephropathy and PCKD had the highest rates (per 1000 person-years) of kidney failure (107.8, 95% CI 71.0–163.8; 75.5, 95% CI 65.6–87.1); whereas, patients with glomerulonephritis and an acquired single kidney had lower rates (52.9, 95% CI 38.8–72.1; 34.6, 95% CI 20.5–58.4, respectively). Among patients with an eGFR ≥ 45 mL/min per 1.73m², those with diabetic nephropathy had the highest rates of kidney failure (16.6, 95% CI 92.5–117.3); whereas, those with glomerulonephritis, PCKD and acquired single kidney had a lower risk (11.3, 95% CI 7.1–17.9; 11.7, 95% CI 3.8–36.2; 10.7, 95% CI 4.0–28.4, respectively).

Conclusion

Patients who developed CKD after nephrectomy had similar rates of adverse events to most other causes of CKD, except for diabetic nephropathy which was consistently associated with worse outcomes. While CKD after nephrectomy is not the most aggressive cause of kidney disease, it is by no means benign, and is associated with a tangible risk of kidney failure and death, which is comparable to other major causes of CKD.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11255-022-03114-7.

Allograft failure in kidney transplant recipients who developed kidney failure secondary to ANCA-associated vasculitis

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides are uncommon causes of kidney failure. In kidney transplant recipients who developed kidney failure secondary to ANCA-associated vasculitis, disease recurrence is unlikely due to ongoing immunosuppression, and patients generally have good immunological outcomes. This study compared transplant outcomes between ANCA-associated vasculitis and other etiologies of kidney disease. All 18 901 adult kidney transplant recipients (1990-2018) were ascertained from the ANZDATA Registry. Cox proportional hazards models were used to compare allograft failure between etiologies of kidney disease. Of 254 participants whose primary disease was ANCA-associated vasculitis, 95 (37%) developed allograft failure; of those who developed graft failure, 62 (65%) died with a functioning allograft. Compared with patients with IgA nephropathy, those with ANCA-associated vasculitis had higher rates of all-cause allograft failure (HR: 1.4, 95% CI: 1.2-1.7); however, rates of death-censored allograft failure were similar (HR: 1.0, 95% CI: 0.7-1.4). The most frequent causes of death in the ANCA-vasculitis group who died with a functioning graft were infection (23%) and malignancy (36%). Kidney transplant recipients who developed kidney failure secondary to ANCA-associated vasculitis may have had a higher risk of dying due to complications of immunosuppression compared with most other causes of kidney failure; however, they also had lower risks of disease recurrence and rejection.

Variability in surgical management of kidney cancer between urban and rural hospitals in Queensland, Australia: a population-based analysis

Background

International guidelines recommend partial over radical nephrectomy for management of kidney tumours, due to perceived advantages of kidney function preservation. In Queensland, oncological nephrectomy is performed in both metropolitan and rural hospitals. Previous studies have shown that patients from rural areas with kidney tumours are less likely to undergo partial nephrectomy compared with those in major cities. The aim of this study was to investigate patterns of partial nephrectomy according to geographical area, and to identify patient- and health-service-level characteristics associated with partial nephrectomy.

Methods

All 3,799 incident kidney cancer cases in Queensland (Jan 2009 to Dec 2014) were ascertained. Patients aged <18 yrs (n=47), who did not receive surgery (n=988), or had end-stage kidney disease (ESKD) before surgery (n=17) were excluded. The final sample included 2,747 patients. Data were analysed using multivariable logistic regression in order to identify associations with partial nephrectomy.

Results

Of 2,747 patients, 637 (25%) underwent partial nephrectomy. The likelihood of undergoing partial nephrectomy increased with more recent year of surgery (P<0.001) and higher socioeconomic status (P<0.001). The likelihood of undergoing partial nephrectomy decreased for patients managed in lower-volume centres (P=0.004), with increasing age (P<0.001), and hospital location outside of a major city (P<0.001). Overall, the number of nephrectomies, and proportion/number of partial nephrectomies, performed in rural hospitals has increased over the study period.

Conclusions

Our results suggest that, although patients who are managed in major cities are more likely to undergo partial nephrectomy, likelihood of undergoing partial nephrectomy in rural centres is increasing, consistent with international best practice.

Haemodialysis withdrawal in Australia and New Zealand: a binational registry study

BACKGROUND

Withdrawal from dialysis is an increasingly common cause of death in patients with end-stage kidney disease (ESKD). As most published reports of dialysis withdrawal have been outside the Oceania region, the aims of this study were to determine the frequency, temporal pattern and predictors of dialysis withdrawal in Australian and New Zealand patients receiving chronic haemodialysis.

METHODS

This study included all people with ESKD in Australia and New Zealand who commenced chronic haemodialysis between 1 January 1997 and 31 December 2016, using data from the Australia and New Zealand Dialysis and Transplant (ANZDATA) Registry. Competing risk regression models were used to identify predictors of dialysis withdrawal mortality, using non-withdrawal cause of death as the competing risk event.

RESULTS

Among 40 447 people receiving chronic haemodialysis (median age 62 years, 61% male, 9% Indigenous), dialysis withdrawal mortality rates increased from 1.02 per 100 patient-years (11% of all deaths) during the period 1997-2000 to 2.20 per 100 patient-years (32% of all deaths) during 2013-16 (P < 0.001). Variables that were significantly associated with a higher likelihood of haemodialysis withdrawal were older age {≥70 years subdistribution hazard ratio [SHR] 1.77 [95% confidence interval (CI) 1.66-1.89]; reference 60-70 years}, female sex [SHR 1.14 (95% CI 1.09-1.21)], white race [Asian SHR 0.56 (95% CI 0.49-0.65), Aboriginal and Torres Strait Islander SHR 0.83 (95% CI 0.74-0.93), Pacific Islander SHR 0.47 (95% CI 0.39-0.68), reference white race], coronary artery disease [SHR 1.18 (95% CI 1.11-1.25)], cerebrovascular disease [SHR 1.15 (95% CI 1.08-1.23)], chronic lung disease [SHR 1.13 (95% CI 1.06-1.21)] and more recent era [2013-16 SHR 3.96 (95% CI 3.56-4.48); reference 1997-2000].

CONCLUSIONS

Death due to haemodialysis withdrawal has become increasingly common in Australia and New Zealand over time. Predictors of haemodialysis withdrawal include older age, female sex, white race and haemodialysis commencement in a more recent era.

A Simple Clinical Tool for Stratifying Risk of Clinically Significant CKD after Nephrectomy: Development and Multinational Validation

BACKGROUND

Clinically significant CKD following surgery for kidney cancer is associated with increased morbidity and mortality, but identifying patients at increased CKD risk remains difficult. Simple methods to stratify risk of clinically significant CKD after nephrectomy are needed.

METHODS

To develop a tool for stratifying patients' risk of CKD arising after surgery for kidney cancer, we tested models in a population-based cohort of 699 patients with kidney cancer in Queensland, Australia (2012-2013). We validated these models in a population-based cohort of 423 patients from Victoria, Australia, and in patient cohorts from single centers in Queensland, Scotland, and England. Eligible patients had two functioning kidneys and a preoperative eGFR ≥60 ml/min per 1.73 m². The main outcome was incident eGFR <45 ml/min per 1.73 m² at 12 months postnephrectomy. We used prespecified predictors-age ≥65 years old, diabetes mellitus, preoperative eGFR, and nephrectomy type (partial/radical)-to fit logistic regression models and grouped patients according to degree of risk of clinically significant CKD (negligible, low, moderate, or high risk).

RESULTS

Absolute risks of stage 3b or higher CKD were <2%, 3% to 14%, 21% to 26%, and 46% to 69% across the four strata of negligible, low, moderate, and high risk, respectively. The negative predictive value of the negligible risk category was 98.9% for clinically significant CKD. The c statistic for this score ranged from 0.84 to 0.88 across derivation and validation cohorts.

CONCLUSIONS

Our simple scoring system can reproducibly stratify postnephrectomy CKD risk on the basis of readily available parameters. This clinical tool's quantitative assessment of CKD risk may be weighed against other considerations when planning management of kidney tumors and help inform shared decision making between clinicians and patients.

Kidney cancer biobanking: considerations for a single institutional biorepository

The Princess Alexandra Hospital Kidney Cancer Biobank, housed at the Translational Research Institute in Brisbane, is an Australian biorepository which contains fixed and fresh-frozen cancer and non-cancer kidney tissue, perinephric fat, urine and peripheral blood. The patient samples are linked to de-identified clinical information via a secure database. Participants undergoing nephrectomy for suspected renal malignancy are recruited prospectively. Recruitment began in 2013 and the biobank currently contains biofluids, tissue and clinical information for more than 330 participants. This biobank contains linked de-identified clinical data, which provide comprehensive information about biospecimens, and information about clinical outcomes.

Tumor size and postoperative kidney function following radical nephrectomy

Background: Chronic kidney disease (CKD) following nephrectomy for kidney tumors is common, and both patient and tumor characteristics may affect postoperative kidney function. Several studies have reported that surgery for large tumors is associated with a lower likelihood of postoperative CKD, but others have reported CKD to be more common before surgery in patients with large tumors. Objective: The aim of this study was to clarify inconsistencies in the literature regarding the prognostic significance of tumor size for postoperative kidney function. Study design and setting: We analyzed data from 944 kidney cancer patients managed with radical nephrectomy between January 2012 and December 2013, and 242 living kidney donors who underwent surgery between January 2011 and December 2014 in the Australian states of Queensland and Victoria. Multivariable logistic regression was used to assess the primary outcome of CKD upstaging. Structural equation modeling was used to evaluate causal models, to delineate the influence of patient and tumor characteristics on postoperative kidney function. Results: We determined that a significant interaction between age and tumor size (P=0.03) led to the observed inverse association between large tumor size and CKD upstaging, and was accentuated by other forms of selection bias. Subgrouping patients by age and tumor size demonstrated that all patients aged ≥65 years were at increased risk of CKD upstaging, regardless of tumor size. Risk of CKD upstaging was comparable between age-matched living donors and kidney cancer patients. Conclusion: Larger tumors are unlikely to confer a protective effect with respect to postoperative kidney function. The reason for the previously reported inconsistency is likely a combination of the analytical approach and selection bias.

Utility of cytokeratin 7, S100A1 and caveolin-1 as immunohistochemical biomarkers to differentiate chromophobe renal cell carcinoma from renal oncocytoma

Background

Differentiation of chromophobe renal cell carcinoma (chRCC) from benign renal oncocytoma (RO) can be challenging especially when there are overlapping histological and morphological features. In this study we have investigated immunohistochemical biomarkers (cytokeratin 7/CK7, Caveolin-1/Cav-1 and S100 calcium-binding protein A1/S100A1) to aid in this difficult differentiation and attempted to validate their use in human renal tumour tissue to assess their discriminatory ability, particularly for chRCC and RO, in an Australian cohort of patients.

Methods

Retrospective study was carried out of archived formalin-fixed paraffin-embedded renal tumours from tumour nephrectomy specimens of 75 patients: 30 chRCC, 15 RO and 30 clear cell RCC (ccRCC). Sections were cut and immunostained with specific polyclonal antibodies of CK7, Cav-1 and S100A1. Morphometry was used to determine expression patterns of the biomarkers using Aperio ImageScope. Results were assessed with student t-test and ANOVA with significance at P<0.05.

Results

From this cohort, male-to-female ratio was 1.9:1. Median age was 64 (45-88 years) and median tumour size was 3.8 cm (range, 1.2-18 cm). There were 47 (62.7%) T1, 7 T2, 20 T3 and one T4 stage of RCC; with 2 patients presenting with M1 stage. There was significantly higher CK7 expression in chRCC compared to RO (P=0.03), and chRCC also had a different staining pattern and higher expression of Cav-1 compared to RO. There was higher expression of S100A1 in RO compared to chRCC.

Conclusions

Immunohistochemical staining and standard morphometry of CK7, Cav-1 and S100A1 can aid in the differentiation of chRCC and RO. This may guide clinicians in management of patients when faced with difficult diagnostic histological distinction between the two tumour subtypes.

Chronic kidney disease after nephrectomy: a clinically-significant entity?

Worldwide, the kidney is the ninth and 14th most common primary site of cancer in men and women respectively. Surgical management with either radical or partial nephrectomy is the mainstay of treatment. Surgical resection of functional kidney parenchyma is associated with reductions in glomerular filtration rate, and can lead to the development of chronic kidney disease (CKD); however, there is currently debate as to whether CKD secondary to surgical removal of a kidney is of clinical significance. Here, it will be argued that CKD is of clinical significance regardless of aetiology, due to the higher cardiovascular and mortality risk which is associated with low glomerular filtration rate.

Incident Chronic Kidney Disease After Radical Nephrectomy for Renal Cell Carcinoma

BACKGROUND

Chronic kidney disease (CKD) after surgery for kidney cancer is common, and is associated with increased morbidity and mortality. This study aimed to identify factors associated with incident CKD in patients managed with radical nephrectomy.

PATIENTS AND METHODS

All patients diagnosed with renal cell carcinoma between January 2012 and December 2013 were ascertained from state-based cancer registries in Queensland and Victoria. Information on patient, tumor, and health service characteristics was obtained via chart review. Multivariable logistic regression was used to evaluate exposures associated with incident CKD (estimated glomerular filtration rate [eGFR] <60 mL per minute per 1.73 m²) at 12 months after nephrectomy.

RESULTS

Older age (adjusted odds ratio [aOR] per 5-year increase, 1.5; 95% confidence interval [CI], 1.4-1.6), male sex (aOR, 1.4; 95% CI, 1.0-2.0), obese compared with not obese (aOR, 1.8; 95% CI, 1.2-2.7), rural compared with urban place of residence (aOR, 1.8; 95% CI, 1.1-3.0) were associated with a higher risk of incident CKD. Lower preoperative eGFR was also associated with a higher risk of incident CKD. Management in private compared with public hospitals was also associated with a higher risk of CKD (aOR, 1.6; 95% CI, 1.2-2.2). Factors related to tumor size and cancer severity were also associated with worse postoperative kidney function, although it is likely this was a consequence of selection bias.

CONCLUSION

Patient characteristics have the strongest associations with incident CKD after radical nephrectomy. Potential risk factors were reasonably similar to recognized CKD risk factors for the general population. Patients who undergo nephrectomy who have CKD risk factors might benefit from ongoing postoperative screening for deterioration of kidney function.

GRP78 expression in tumor and perinephric adipose tissue is not an optimal risk stratification marker for clear cell renal cell carcinoma

Objective

Clear cell renal cell carcinoma (ccRCC) is the most common subtype of kidney cancer, which is difficult to treat and lacks a reliable prognostic marker. A previous study showed that the endoplasmic reticulum stress marker, glucose-regulated-protein-78 (GRP78), is a potential prognostic marker for ccRCC. The present study aimed to: (1) examine whether GRP78 was upregulated in ccRCC compared with matched non-neoplastic renal tissue; and (2) investigate whether GRP78 expression in ccRCC tissue or perinephric adipose tissue has any association with ccRCC aggressiveness.

Methods

A retrospective cross-sectional study of 267 patients who underwent nephrectomy for renal tumors between June 2013 and October 2017 was conducted at Princess Alexandra Hospital, Brisbane, Australia. Software-assisted quantification of average grey value of staining intensity (staining intensity method) and proportion of positive pixels (positive pixel method) was applied to measure expression of GRP78 in archived specimens of renal tumor tissues (n = 114), adjacent non-neoplastic renal tissues (n = 68), and perinephric adipose tissues (n = 60) in participants diagnosed with ccRCC.

Results

GRP78 was not upregulated in renal tumor tissue compared with paired normal renal tissue. In tumor tissue, GRP78 expression did not show any association with ccRCC aggressiveness using either quantification method. In adipose tissue, downregulation of GRP78 demonstrated poor correlation with increased probability of metastasis, with one unit increase in average grey value of GRP78 staining weakly correlating with a 17% increase in the odds ratio of metastasis (95% confidence interval: 0.99 to 1.38, p = 0.07).

Conclusion

GRP78 is not valuable as a risk stratification marker for ccRCC.

Chronic kidney cortical damage is associated with baseline kidney function and albuminuria in patients managed with radical nephrectomy for kidney tumours

This study evaluated the relationship between histological markers of chronic kidney damage in patients undergoing radical nephrectomy for kidney tumours and preoperative kidney function, degree of albuminuria, and changes in glomerular volume. A schema to grade chronic kidney damage could be used to identify patients at risk of developing CKD following nephrectomy. Non-neoplastic cortical tissue was sourced from 150 patients undergoing radical nephrectomy for suspected kidney cancer. This tissue was evaluated for indicators of chronic damage, specifically: glomerulosclerosis, arteriosclerosis, interstitial fibrosis, and tubular atrophy. Glomerular volume was determined using the Weibel and Gomez method. Associations between these parameters and both estimated glomerular filtration rate (eGFR) and albumin-creatinine ratio (ACR) were determined using either a Mann-Whitney U-test or a Kruskal-Wallis ANOVA. Associations between both eGFR and ACR and glomerular volume were assessed using linear regression. eGFR was inversely associated with the degree of glomerulosclerosis (p < 0.001), vascular narrowing (p = 0.002), tubular atrophy (p < 0.001), and interstitial fibrosis (p < 0.001). ACR was associated only with the degree of interstitial fibrosis (p = 0.02) and tubular atrophy (p = 0.02). Glomerular volume was greater for males, diabetics, hypertensive patients, and patients with a greater degree of interstitial fibrosis. Glomerular volume was positively associated with ACR. A schema to grade chronic damage was developed. The proposed schema is associated with baseline clinical indices of kidney function and damage. Longitudinal validation is necessary to determine the prognostic utility of this schema.

End-Stage Kidney Disease following Surgical Management of Kidney Cancer

BACKGROUND AND OBJECTIVES

We investigated the incidence of ESKD after surgical management of kidney cancer in the Australian state of Queensland, and described patterns in the initiation of kidney replacement therapy resulting from kidney cancer across Australia.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

All newly diagnosed cases of kidney cancer in the Australian state of Queensland between January of 2009 and December of 2014 were ascertained through the Queensland Cancer Registry. There were 2739 patients included in our analysis. Patients who developed ESKD were identified using international classification of disease-10-coded hospital administrative data. Incidence rate and 3-year cumulative incidence were calculated, and multivariable Cox proportional hazards models were used to identify factors associated with ESKD. Additional descriptive analysis was undertaken of Australian population data.

RESULTS

The incidence rate of ESKD in all patients was 4.9 (95% confidence interval [95% CI], 3.9 to 6.2) per 1000 patient-years. The 3-year cumulative incidence was 1.7%, 1.9%, and 1.0% for all patients, and patients managed with radical or partial nephrectomy, respectively. Apart from preoperative kidney disease, exposures associated with increased ESKD risk were age≥65 years (adjusted hazard ratio [aHR], 2.0; 95% CI, 1.2 to 3.2), male sex (aHR, 2.3; 95% CI, 1.3 to 4.3), preoperative diabetes (aHR, 1.8; 95% CI, 1.0 to 3.3), American Society of Anesthesiologists classification ≥3 (aHR, 4.0; 95% CI, 2.2 to 7.4), socioeconomic disadvantage (aHR, 1.6; 95% CI, 0.9 to 2.7), and postoperative length of hospitalization ≥6 days (aHR, 2.1; 95% CI, 1.4 to 3.0). Australia-wide trends indicate that the rate of kidney replacement therapy after oncologic nephrectomy doubled between 1995 and 2015, from 0.3 to 0.6 per 100,000 per year.

CONCLUSIONS

In Queensland between 2009 and 2014, one in 53 patients managed with radical nephrectomy and one in 100 patients managed with partial nephrectomy developed ESKD within 3 years of surgery.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2018_09_28_CJASNPodcast_18_1_.mp3.

Longitudinal study on the occurrence in pigs of colistin-resistant Escherichia coli carrying mcr-1 following the cessation of use of colistin

AIMS

In 2015, colistin-resistant Escherichia coli and Salmonella with the mcr-1 gene were isolated from a pig farm in Great Britain. Pigs were subsequently monitored over a ~20-month period for the occurrence of mcr-1-mediated colistin resistance and the risk of mcr-1 E. coli entering the food chain was assessed.

METHODS AND RESULTS

Pig faeces and slurry were cultured for colistin-resistant E. coli and Salmonella, tested for the mcr-1 gene by PCR and selected isolates were further analysed. Seventy-eight per cent of faecal samples (n = 275) from pigs yielded mcr-1 E. coli after selective culture, but in positive samples only 0·2-1·3% of the total E. coli carried mcr-1. Twenty months after the initial sampling, faecal samples (n = 59) were negative for E. coli carrying mcr-1.

CONCLUSIONS

The risk to public health from porcine E. coli carrying mcr-1 was assessed as very low. Twenty months after cessation of colistin use, E. coli carrying mcr-1 was not detected in pig faeces on a farm where it was previously present.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results suggest that cessation of colistin use may help over time to reduce or possibly eliminate mcr-1 E. coli on pig farms where it occurs.

Predictors of new-onset chronic kidney disease in patients managed surgically for T1a renal cell carcinoma: An Australian population-based analysis

BACKGROUND

New-onset chronic kidney disease (CKD) following surgical management of kidney tumors is common. This study evaluated risk factors for new-onset CKD after nephrectomy for T1a renal cell carcinoma (RCC) in an Australian population-based cohort.

METHODS

There were 551 RCC patients from the Australian states of Queensland and Victoria included in this study. The primary outcome was new-onset CKD (eGFR <60 mL/min per 1.73 m² ) and the secondary outcome was new-onset moderate-severe CKD (<45 mL/min per 1.73 m² ). Multivariable logistic regression was used to evaluate associations between patient, tumor and health-service characteristics and these outcomes.

RESULTS

Forty percent (219/551) of patients developed new-onset CKD, and 12% (68/551) experienced new-onset moderate-severe CKD. Risk factors for new-onset CKD were age, lower preoperative eGFR, tumor size >20 mm, radical nephrectomy, lower hospital caseloads (<20 cases/year), and rural place of residence. The associations between rural place of residence and low center volume were a consequence of higher radical nephrectomy rates.

CONCLUSION

Risk factors for CKD after nephrectomy generally relate to worse baseline health, or likelihood of undergoing radical nephrectomy. Surgeons in rural centres and hospitals with low caseloads may benefit from formalized integration with specialist centers for continued professional development and case-conferencing, to assist in management decisions.

Outcome Measures Used to Report Kidney Function in Studies Investigating Surgical Management of Kidney Tumours: A Systematic Review

CONTEXT

Most practice decisions relevant to preserving kidney function in patients managed surgically for kidney tumours are driven by observational studies. A wide range of outcome measures are used in these studies, which reduces comparability and increases the risk of reporting bias.

OBJECTIVE

To comprehensively and succinctly describe the outcomes used to evaluate kidney function in studies evaluating surgical management of kidney tumours.

EVIDENCE ACQUISITION

Electronic search of the PubMed database was conducted to identify studies with at least one measure of kidney function in patients managed surgically for kidney tumours, published between January 2000 and September 2017. Abstracts were initially screened for eligibility. Full texts of articles were then evaluated in more detail for inclusion. A narrative synthesis of the evidence was conducted.

EVIDENCE SYNTHESIS

A total of 312 studies, involving 127905 participants, were included in this review. Most were retrospective (n=274) studies and conducted in a single centre (n=264). Overall, 78 unique outcome measures were identified, which were grouped into six outcome categories. Absolute postoperative kidney function (n=187), relative kidney function (n=181), and postoperative chronic kidney disease (n=131) were most frequently reported. Kidney function was predominantly quantified using estimated glomerular filtration rate or creatinine clearance (n=255), most using the modification of diet in renal disease equation (n=182). Only 70 studies provided rationale for specific outcome measures used.

CONCLUSIONS

There is significant variability in the reporting and quantification of kidney function in studies evaluating patients managed surgically for kidney tumours. A standardised approach to measuring and reporting kidney function will increase the effectiveness of outcomes reported and improve relevance of research findings within a clinical context.

PATIENT SUMMARY

Although we know that the removal of a kidney can reduce kidney function, clinical significance of various approaches is a matter of debate. This article demonstrates significant variability in the way kidney function was reported across all studies of patients with kidney cancer undergoing surgery, indicating a need for standardisation.

Indoxyl Sulfate Induces Apoptosis and Hypertrophy in Human Kidney Proximal Tubular Cells

Indoxyl sulfate (IS) is a protein-bound uremic toxin that accumulates in patients with declining kidney function. Although generally thought of as a consequence of declining kidney function, emerging evidence demonstrates direct cytotoxic role of IS on endothelial cells and cardiomyocytes, largely through the expression of pro-inflammatory and pro-fibrotic factors. The direct toxicity of IS on human kidney proximal tubular epithelial cells (PTECs) remains a matter of debate. The current study explored the effect of IS on primary cultures of human PTECs and HK-2, an immortalized human PTEC line. Pathologically relevant concentrations of IS induced apoptosis and increased the expression of the proapoptotic molecule Bax in both cell types. IS impaired mitochondrial metabolic activity and induced cellular hypertrophy. Furthermore, statistically significant upregulation of pro-fibrotic (transforming growth factor-β, fibronectin) and pro-inflammatory molecules (interleukin-6, interleukin-8, and tumor necrosis factor-α) in response to IS was observed. Albumin had no influence on the toxicity of IS. The results of this study suggest that IS directly induced a pro-inflammatory and pro-fibrotic phenotype in proximal tubular cells. In light of the associated apoptosis, hypertrophy, and metabolic dysfunction, this study demonstrates that IS may play a role in the progression of chronic kidney disease.

The Correlates of Kidney Dysfunction – Tumour Nephrectomy Database (CKD-TUNED) Study: Protocol for a Prospective Observational Study

Background:

Tumour nephrectomy conveys a significant risk of adverse renal functional outcomes postoperatively, however there are limited strategies for predicting patients at increased risk of these outcomes. The Correlates of Kidney Dysfunction – Tumour Nephrectomy Database (CKD-TUNED) study is a prospective observational study evaluating the risk of chronic kidney disease and end-stage kidney disease in tumour nephrectomy patients.

Methods:

The CKD-TUNED study involves analysis of clinical data and collection of tissue, urine and blood samples for the purposes of forming a tissue repository resource for future investigation. Recruitment began in 2013 and is expected to continue until 2023, with a projected sample size between 700-1000 subjects.

Results:

All relevant ethics and site-specific approvals have been granted and all relevant infrastructure is in place. Study methods are undergoing validation and refinement. As of June 2017 there are 267 participants enrolled in the study.

Conclusion:

It is anticipated that this study will have the potential to identify risk factors for adverse renal functional outcomes following tumour nephrectomy, which can be used in the development of predictive models with clinical utility, and in turn improve patient outcomes.

Factors associated with acutely elevated serum creatinine following radical tumour nephrectomy: the Correlates of Kidney Dysfunction-Tumour Nephrectomy Database study

BACKGROUND

To identify factors associated with acutely elevated serum creatinine (SCr) within 7 days of radical tumour nephrectomy.

METHODS

The study population consisted of 130 consecutive patients managed for renal tumours. The primary outcome was acute kidney injury (AKI) (defined as SCr increase ≥50% above baseline), assessed using multivariable logistic regression analysis. The secondary outcome was SCr percentage increase, assessed using multivariable linear regression analysis.

RESULTS

Following nephrectomy, the mean percentage increase in SCr in the first week was 55%±29%, and 77 (59%) patients experienced AKI. Independent predictors of AKI post-nephrectomy were male gender [adjusted odds ratio (OR): 2.67; 95% confidence interval (95% CI): 1.01, 6.93], urine albumin-creatinine ratio (OR: 0.66; 95% CI: 0.47, 0.91), preoperative estimated glomerular filtration rate (eGFR) (OR: 1.03; 95% CI: 1.00, 1.05), laparoscopic nephrectomy (OR: 3.02; 95% CI: 1.00, 9.12), and non-clear cell renal cell carcinoma (RCC) (OR: 2.93; 95% CI: 1.04, 8.29). Independent predictors of a SCr increase were male gender (β: 12.0; 95% CI: 2.69, 21.3), urine albumin-creatinine ratio (β: -3.36; 95% CI: -6.55, -0.16), preoperative eGFR (β: 0.38; 95% CI: 0.10, 0.66), laparoscopic nephrectomy (β: 12.7; 95% CI: 1.05, 24.3) and obesity (β: 9.94, 95% CI: 0.61, 19.3).

CONCLUSIONS

Male gender, albuminuria, eGFR and laparoscopic nephrectomy independently associated with acutely elevated serum creatinine following radical tumour nephrectomy.

Engagement and outcomes in a digital Diabetes Prevention Program: 3-year update

OBJECTIVE

Translations of the Diabetes Prevention Program (DPP) have proliferated in recent years, with increasing expansion to digital formats. Although these DPP translations have consistently shown favorable clinical outcomes, long-term data for digital formats are limited. This study's objective was to examine clinical outcomes up to 3 years post-baseline and the relationship between program engagement and clinical outcomes in a digital DPP.

RESEARCH DESIGN AND METHODS

In a single-arm, non-randomized trial, 220 patients previously diagnosed with prediabetes were enrolled in the Omada Health Program, a commercially available, 16-week DPP-based weight loss intervention followed by an ongoing weight maintenance intervention. Changes in body weight and A1c were assessed annually. Relationships between program engagement during the first year and clinical outcomes across 3 years were examined.

RESULTS

Participants were socioeconomically diverse (62% women, 50.2% non-Hispanic white, 51.7% college educated or higher). From baseline to 3 years, those participants who completed four or more lessons and nine or more lessons achieved significant sustained weight loss (-3.0% and -2.9%, respectively) and an absolute reduction in A1c (-0.31 and -0.33, respectively) with an average remission from the prediabetes range to the normal glycemic range. Factor analysis of engagement metrics during the first year revealed two underlying dimensions, one comprising lesson completion and health behavior tracking consistency, and the other comprising website logins and group participation. When these two factors were used to predict weight loss, only the logins and group participation factor was a significant predictor of weight loss at 16 weeks and 1 year.

CONCLUSIONS

This study demonstrates significant long-term reductions in body weight and A1c in a digital DPP and identifies patterns of program engagement that predict weight loss.

Significance of Co-expression of Epidermal Growth Factor Receptor and Ki67 on Clinical Outcome in Patients With Anal Cancer Treated With Chemoradiotherapy: An Analysis of NRG Oncology RTOG 9811

PURPOSE

To measure co-expression of EGFR and Ki67 proteins in pretreatment tumor biopsies of anal cancer patients enrolled on NRG Oncology RTOG 9811, a phase III trial comparing 5-fluorouracil/mitomycin-C/radiation therapy (Arm A) versus 5-fluorouracil/cisplatin/radiation therapy (Arm B), and to correlate expression with clinical outcome.

METHODS AND MATERIALS

EGFR and Ki67 co-expression was measured after constructing a tissue microarray using fluorescence immunohistochemistry and automated quantitative image analysis. The Ki67 score within EGFR high versus low areas (Ki67ratio in EGFR_high:low) in each tumor core was analyzed at the median, quartiles, and as a continuous variable. Associations between the tumor markers and clinical endpoints (overall and disease-free survival, locoregional and colostomy failure, and distant metastases) were explored.

RESULTS

A total of 282 pretreatment tumors were analyzed from NRG Oncology RTOG 9811. Of evaluated specimens, 183 (65%, n=89, Arm A; n=94, Arm B) were eligible and analyzable. There were no significant differences in baseline characteristics or outcomes between analyzable and unanalyzable patient cases. Median follow-up was 6.0 years. On multivariate analysis, after adjusting for gender, patients with Ki67ratio in EGFR_high:low ≥median had worse overall survival (hazard ratio 2.41, 95% confidence interval 1.38-4.19, P=.0019). After adjusting for N stage and largest tumor dimension, patients with Ki67ratio in EGFR_high:low ≥ median had a higher risk of a disease-free failure (hazard ratio 1.85, 95% confidence interval 1.18-2.92, P=.0078). Technical validation with an independent anal cancer patient cohort was performed and shows a very similar biomarker score distribution.

CONCLUSIONS

High Ki67ratio in EGFR_high:low is associated with worse clinical outcome in this subset of patients with anal cancer treated with chemoradiation on NRG Oncology RTOG 9811. Evaluation within a clinical trial will be required to determine whether patients with these tumor characteristics may specifically benefit from an EGFR-targeted therapeutic agent.

Indoxyl sulphate and kidney disease: Causes, consequences and interventions

In the last decade, chronic kidney disease (CKD), defined as reduced renal function (glomerular filtration rate (GFR) < 60 mL/min per 1.73 m(2) ) and/or evidence of kidney damage (typically manifested as albuminuria) for at least 3 months, has become one of the fastest-growing public health concerns worldwide. CKD is characterized by reduced clearance and increased serum accumulation of metabolic waste products (uremic retention solutes). At least 152 uremic retention solutes have been reported. This review focuses on indoxyl sulphate (IS), a protein-bound, tryptophan-derived metabolite that is generated by intestinal micro-organisms (microbiota). Animal studies have demonstrated an association between IS accumulation and increased fibrosis, and oxidative stress. This has been mirrored by in vitro studies, many of which report cytotoxic effects in kidney proximal tubular cells following IS exposure. Clinical studies have associated IS accumulation with deleterious effects, such as kidney functional decline and adverse cardiovascular events, although causality has not been conclusively established. The aims of this review are to: (i) establish factors associated with increased serum accumulation of IS; (ii) report effects of IS accumulation in clinical studies; (iii) critique the reported effects of IS in the kidney, when administered both in vivo and in vitro; and (iv) summarize both established and hypothetical therapeutic options for reducing serum IS or antagonizing its reported downstream effects in the kidney.

Self-Monitoring and Leadership Emergence

The research described here was directed toward furthering our understanding of the antecedents of leadership emergence in groups. Kenny and Zaccaro (1983) have recently speculated that individuals who emerge as leaders may be able to perceive the needs of their group and pattern their own behavior accordingly. Past research strongly supports the notion that individuals who are high self-monitors possess skills corresponding to both these characteristics. Thus the present research examined the relationship between self-monitoring and leadership emergence in a long-term field study of natural groups. The expectation that high self-monitoring would be associated with leadership emergence received strong support. The implications of these results for furthering our understanding of the nature of self-monitoring and leadership are discussed.

Self-Monitoring and Leader Emergence

The present research seeks to further understanding of the relationship between self-monitoring and leader emergence in groups. It does so by focusing on two proposed moderators of this relationship: sex of the group members and nature of the task confronting the group. On the basis of previous research, it was hypothesized that high self-monitoring would be related to leader emergence for males, but not for females, in mixed-sex groups. Further, the relationship between self-monitoring and leader emergence was hypothesized to be stronger for a task providing minimal feedback on the task competence of group members. These hypotheses were tested in a long-term study of natural mixed-sex groups. The sex-moderator hypothesis was supported, but the task-moderator hypothesis was not. Post hoc analyses suggested that high self-monitors emerge as group leaders because they are more adaptive in their behavior than low self-monitors. Both theoretical and practical implications of the results are discussed.

A Process Investigation of Self-Monitoring and Leader Emergence

Although previous research has shown that high self-monitors tend to emerge as group leaders, little is known about the processes by which this personality trait influences leader emergence. Extrapolating from self-monitoring theory (Snyder, 1987), it was postulated that high self-monitors emerge as group leaders because they are sensitive to, and act on, social cues regarding appropriate leader style, whereas low self-monitors emerge as leaders as a function of favorable attitudes toward leadership. Two hypotheses corresponding to these postulates were tested in a laboratory experiment conducted on 68 business students assigned to 4-person problem-solving groups in an organization simulation. Both hypotheses were supported, thus showing the value of self-monitoring theory for furthering the understanding of leader emergence within groups. The implications of these findings for selfmonitoring theory, as well as for the measurement and development of organization leadership, are explored.

Validating Objective Versus Subjective Judgments

Perceivers' interest in social comparison and consistency information for assessing the accuracy of a personal judgment was investigated. Prior to their judging a photograph of a woman, male subjects' perceptions of the causal locus of beauty were manipulated. Subjects were told they would rate the woman again and were asked how interested they were before making their second judgment in seeing (a) additional photographs of the woman (consistency information) and (b) other male subjects' ratings of the woman's attractiveness (consensus or social comparison information). Subjects expressed greater interest in consistency than consensus information. Subjects were more interested in consensus information when they saw beauty as objective than when they saw beauty as subjective. Implications of these results for social comparison theory are discussed.

Self-Monitoring and Leadership Emergence in Groups

The research described here was directed toward furthering our understanding of the antecedents of leadership emergence in groups. In particular, it sought to identify important personality characteristics associated with this phenomenon. Kenny and Zaccaro (1983) have recently speculated that individuals who emerge as leaders may be able to perceive the needs of the group and pattern their own behavior accordingly. Past research strongly supports the notion that individuals who are high in the personality dimension of self-monitoring possess skills corresponding to both these characteristics. The present research examined the effects of self-monitoring on leadership emergence in a study of natural groups. The expectation that high self-monitoring would be associated with leadership emergence was strongly supported for male participants. The implications of these results for increasing our knowledge of the nature of self-monitoring and leadership were discussed.

Brain connectivity reflects human aesthetic responses to music

Humans uniquely appreciate aesthetics, experiencing pleasurable responses to complex stimuli that confer no clear intrinsic value for survival. However, substantial variability exists in the frequency and specificity of aesthetic responses. While pleasure from aesthetics is attributed to the neural circuitry for reward, what accounts for individual differences in aesthetic reward sensitivity remains unclear. Using a combination of survey data, behavioral and psychophysiological measures and diffusion tensor imaging, we found that white matter connectivity between sensory processing areas in the superior temporal gyrus and emotional and social processing areas in the insula and medial prefrontal cortex explains individual differences in reward sensitivity to music. Our findings provide the first evidence for a neural basis of individual differences in sensory access to the reward system, and suggest that social-emotional communication through the auditory channel may offer an evolutionary basis for music making as an aesthetically rewarding function in humans.

Two-week test-retest reliability of the Polar® RS800CX™ to record heart rate variability

Recently, research has validated the use of Polar^® heart rate monitors as a tool to index heart rate variability (HRV). In the current investigation, we sought to evaluate the test-retest reliability of both time and frequency domain measures of HRV using the Polar^® RS800CX^™ . Continuous HRV data were collected as 60 nominally healthy adults underwent a resting and orthostatic stress test. We evaluated reproducibility by means of the interclass correlation coefficient for absolute agreement and consistency, and the standard error of measurement. We found moderate reliable 2-week test-retest reliability of HRV using the Polar^® RS800CX^™ , results that are in line with previous studies that have validated the stability of HRV using other methods of measurement (e.g. electrocardiogram). Additionally, when examining different methods of spectral density estimation, we found that using the auto-regressive transformation method provides the most stable indices of HRV. Taken together, our results suggest that the Polar^® RS800CX^™ is not only a valid method to record HRV, but also a reliable one, particularly when using the auto-regressive transformation method.

Pneumogastric (Vagus) Nerve Activity Indexed by Heart Rate Variability in Chronic Pain Patients Compared to Healthy Controls: A Systematic Review and Meta-Analysis

BACKGROUND

A large body of scientific literature derived from experimental studies emphasizes the vital role of vagal-nociceptive networks in acute pain processing. However, research on vagal activity, indexed by vagally-mediated heart rate variability (vmHRV) in chronic pain patients (CPPs), has not yet been summarized.

OBJECTIVES

To systematically investigate differences in vagus nerve activity indexed by time- and frequency-domain measures of vmHRV in CPPs compared to healthy controls (HCs).

STUDY DESIGN

A systematic review and meta-analysis, including meta-regression on a variety of populations (i.e., clinical etiology) and study-level (i.e., length of HRV recording) covariates.

SETTING

Not applicable (variety of studies included in the meta-analysis).

METHODS

Eight computerized databases (PubMed via MEDLINE, PsycNET, PsycINFO, Embase, CINAHL, Web of Science, PSYNDEX, and the Cochrane Library) in addition to a hand search were systematically screened for eligible studies based on pre-defined inclusion criteria. A meta-analysis on all empirical investigations reporting short- and long-term recordings of continuous time- (root-mean-square of successive R-R-interval differences [RMSSD]) and frequency-domain measures (high-frequency [HF] HRV) of vmHRV in CPPs and HCs was performed. True effect estimates as adjusted standardized mean differences (SMD; Hedges g) combined with inverse variance weights using a random effects model were computed.

RESULTS

CPPs show lower vmHRV than HCs indexed by RMSSD (Z = 5.47, P < .0001; g = -0.24;95% CI [-0.33, -0.16]; k = 25) and HF (Z = 4.54, P < .0001; g = -0.30; 95% CI [-0.44, -0.17]; k = 61).Meta-regression on covariates revealed significant differences by clinical etiology, age, gender, and length of HRV recording.

LIMITATIONS

We did not control for other potential covariates (i.e., duration of chronic pain, medication intake) which may carry potential risk of bias.

CONCLUSION(S)

The present meta-analysis is the most extensive review of the current evidence on vagal activity indexed by vmHRV in CPPs. CPPs were shown to have lower vagal activity, indexed by vmHRV, compared to HCs. Several covariates in this relationship have been identified. Further research is needed to investigate vagal activity in CPPs, in particular prospective and longitudinal follow-up studies are encouraged.

A Validated Smartphone-Based Assessment of Gait and Gait Variability in Parkinson's Disease

Background

A well-established connection exists between increased gait variability and greater fall likelihood in Parkinson’s disease (PD); however, a portable, validated means of quantifying gait variability (and testing the efficacy of any intervention) remains lacking. Furthermore, although rhythmic auditory cueing continues to receive attention as a promising gait therapy for PD, its widespread delivery remains bottlenecked. The present paper describes a smartphone-based mobile application (“SmartMOVE”) to address both needs.

Methods

The accuracy of smartphone-based gait analysis (utilizing the smartphone’s built-in tri-axial accelerometer and gyroscope to calculate successive step times and step lengths) was validated against two heel contact–based measurement devices: heel-mounted footswitch sensors (to capture step times) and an instrumented pressure sensor mat (to capture step lengths). 12 PD patients and 12 age-matched healthy controls walked along a 26-m path during self-paced and metronome-cued conditions, with all three devices recording simultaneously.

Results

Four outcome measures of gait and gait variability were calculated. Mixed-factorial analysis of variance revealed several instances in which between-group differences (e.g., increased gait variability in PD patients relative to healthy controls) yielded medium-to-large effect sizes (eta-squared values), and cueing-mediated changes (e.g., decreased gait variability when PD patients walked with auditory cues) yielded small-to-medium effect sizes—while at the same time, device-related measurement error yielded small-to-negligible effect sizes.

Conclusion

These findings highlight specific opportunities for smartphone-based gait analysis to serve as an alternative to conventional gait analysis methods (e.g., footswitch systems or sensor-embedded walkways), particularly when those methods are cost-prohibitive, cumbersome, or inconvenient.

Quantifying auditory temporal stability in a large database of recorded music

“Moving to the beat” is both one of the most basic and one of the most profound means by which humans (and a few other species) interact with music. Computer algorithms that detect the precise temporal location of beats (i.e., pulses of musical “energy”) in recorded music have important practical applications, such as the creation of playlists with a particular tempo for rehabilitation (e.g., rhythmic gait training), exercise (e.g., jogging), or entertainment (e.g., continuous dance mixes). Although several such algorithms return simple point estimates of an audio file’s temporal structure (e.g., “average tempo”, “time signature”), none has sought to quantify the temporal stability of a series of detected beats. Such a method-a “Balanced Evaluation of Auditory Temporal Stability” (BEATS)–is proposed here, and is illustrated using the Million Song Dataset (a collection of audio features and music metadata for nearly one million audio files). A publically accessible web interface is also presented, which combines the thresholdable statistics of BEATS with queryable metadata terms, fostering potential avenues of research and facilitating the creation of highly personalized music playlists for clinical or recreational applications.

Brain morphometric correlates of metabolic variables in HIV: the CHARTER study

Obesity and other metabolic variables are associated with abnormal brain structural volumes and cognitive dysfunction in HIV-uninfected populations. Since individuals with HIV infection on combined antiretroviral therapy (CART) often have systemic metabolic abnormalities and changes in brain morphology and function, we examined associations among brain volumes and metabolic factors in the multisite CNS HIV AntiRetroviral Therapy Effects Research (CHARTER) cohort, cross-sectional study of 222 HIV-infected individuals. Metabolic variables included body mass index (BMI), total blood cholesterol (C), low- and high-density lipoprotein C (LDL-C and HDL-C), blood pressure, random blood glucose, and diabetes. MRI measured volumes of cerebral white matter, abnormal white matter, cortical and subcortical gray matter, and ventricular and sulcal CSF. Multiple linear regression models allowed us to examine metabolic variables separately and in combination to predict each regional volume. Greater BMI was associated with smaller cortical gray and larger white matter volumes. Higher total cholesterol (C) levels were associated with smaller cortex volumes; higher LDL-C was associated with larger cerebral white matter volumes, while higher HDL-C levels were associated with larger sulci. Higher blood glucose levels and diabetes were associated with more abnormal white matter. Multiple atherogenic metabolic factors contribute to regional brain volumes in HIV-infected, CART-treated patients, reflecting associations similar to those found in HIV-uninfected individuals. These risk factors may accelerate cerebral atherosclerosis and consequent brain alterations and cognitive dysfunction.

Body mass index is related to autonomic nervous system activity as measured by heart rate variability--a replication using short term measurements

OBJECTIVES

The present analysis is a replication of previous findings presenting first evidence of an association between body mass index (BMI) and autonomic nervous system (ANS) activity as measured by heart rate variability (HRV), in healthy non-obese adults.

DESIGN

A total of fifty-nine apparently healthy male (M) and female (F) individuals (M/F = 15/44) were included in the trial. HRV data for analysis was derived from 5 minutes of baseline recordings, while the subject was sitting on a comfortable chair. Subjects' body measures (weight and height) were taken and BMI was obtained according to common calculation (kg/m²).

RESULTS

BMI was inversely related to pNN50 and RMSSD components of HRV. Statistically significant differences between stratified groups (BMI<20, BMI 20-25, BMI >25) only occurred for analysis of pNN50 components. The pNN50 components and RMSSD are strongly associated with cardiac vagal influence, and thus represents parasympathetic activity.

CONCLUSIONS

The present data supports previous findings, that sympatho-vagal balance is related to BMI in non-obese, healthy individuals, providing evidence for a prominent role of the vagus nerve in the modulation of the energy expenditure of the human organism. Furthermore, this relation can be observed in short term recordings of HRV of 5 minutes in length.

Development of a time-stepping sediment budget model for assessing land use impacts in large river basins

The use of river basin modelling to guide mitigation of non-point source pollution of wetlands, estuaries and coastal waters has become widespread. To assess and simulate the impacts of alternate land use or climate scenarios on river washload requires modelling techniques that represent sediment sources and transport at the time scales of system response. Building on the mean-annual SedNet model, we propose a new D-SedNet model which constructs daily budgets of fine sediment sources, transport and deposition for each link in a river network. Erosion rates (hillslope, gully and streambank erosion) and fine sediment sinks (floodplains and reservoirs) are disaggregated from mean annual rates based on daily rainfall and runoff. The model is evaluated in the Burdekin basin in tropical Australia, where policy targets have been set for reducing sediment and nutrient loads to the Great Barrier Reef (GBR) lagoon from grazing and cropping land. D-SedNet predicted annual loads with similar performance to that of a sediment rating curve calibrated to monitored suspended sediment concentrations. Relative to a 22-year reference load time series at the basin outlet derived from a dynamic general additive model based on monitoring data, D-SedNet had a median absolute error of 68% compared with 112% for the rating curve. RMS error was slightly higher for D-SedNet than for the rating curve due to large relative errors on small loads in several drought years. This accuracy is similar to existing agricultural system models used in arable or humid environments. Predicted river loads were sensitive to ground vegetation cover. We conclude that the river network sediment budget model provides some capacity for predicting load time-series independent of monitoring data in ungauged basins, and for evaluating the impact of land management on river sediment load time-series, which is challenging across large regions in data-poor environments.

The effect of anxiety on heart rate variability, depression, and sleep in chronic obstructive pulmonary disease

OBJECTIVES

The current study investigates heart rate variability (HRV) responses to a psychosocial stressor in chronic obstructive pulmonary disease (COPD) patients, and the potential role of anxiety as a confounding factor in this relationship. Additionally, this study also investigates the influence of anxiety on sleep and depressive symptoms among COPD patients.

METHODS

The study utilized a 2 (disease status)×2 (anxiety group) factorial design examining HRV associated with anxiety symptoms and COPD during a standardized acute social stress task. Participants (mean age 59.1±11.2 years; 50% female) completed pulmonary function testing, HRV monitoring, and self-report questionnaires assessing psychological factors. 30 COPD patients were age- and gender-matched with 30 healthy controls.

RESULTS

HRV response to a psychosocial stressor among participants with higher anxiety (both COPD and healthy) reflected autonomic dysregulation in both time and frequency domains that was not evident among non-anxious participants. COPD participants with higher anxiety reported greater symptoms of depression and poorer sleep quality than did COPD participants with low anxiety.

CONCLUSIONS

Anxiety is associated with dysregulated HRV response to a psychosocial stressor, but the negative influence of anxiety and COPD on autonomic function did not appear to be additive. Comorbid anxiety in patients with COPD is associated with increased behavioral and psychological symptoms of distress.