Outcomes of patients receiving maintenance dialysis admitted over weekends.

BACKGROUND: Hospital admissions over weekends have been associated with worse outcomes in different patient populations. The cause of this difference in outcomes remains unclear; however, different staffing patterns over weekends have been speculated to contribute. We evaluated outcomes in patients on maintenance dialysis therapy admitted over weekends using a national database. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: We included nonelective admissions of adult patients (≥18 years) on maintenance dialysis therapy (n = 3,278,572) identified using appropriate International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes for 2005-2009 using the Nationwide Inpatient Sample database. PREDICTOR: Weekend versus weekday admission. OUTCOMES: The primary outcome measure was all-cause in-hospital mortality. Secondary outcomes included mortality by day 3 of admission, length of hospital stay, time to death, and discharge disposition. MEASUREMENTS: We adjusted for patient and hospital characteristics, payer, year, comorbid conditions, and primary discharge diagnosis common to maintenance dialysis patients. RESULTS: There were an estimated 704,491 admissions over weekends versus 2,574,081 over weekdays. Unadjusted all-cause in-hospital mortality was 40,666 (5.8%) for weekend admissions in comparison to 138,517 (5.4%) for weekday admissions (P < 0.001). In a multivariable model, patients admitted over weekends had higher all-cause in-hospital mortality (OR, 1.06; 95% CI, 1.01-1.10) in comparison to those admitted over weekdays and higher mortality during the first 3 days of admission (OR, 1.18; 95% CI, 1.10-1.26). Patients admitted over weekends were less likely to be discharged to home, had longer hospital stays, and had shorter times to death compared with those admitted over weekdays on adjusted analysis. LIMITATIONS: Use of ICD-9-CM codes to identify patients, defining weekend as midnight Friday to midnight Sunday. CONCLUSIONS: Maintenance dialysis patients admitted over weekends have increased mortality rates and longer lengths of stay compared with those admitted over weekdays. Further studies are needed to identify the reasons for worse outcomes for weekend admissions in this patient population.

Renal dysfunction is common among adults after palliation for previous tetralogy of Fallot.

Long-term survival after tetralogy of Fallot (TOF) repair is excellent. However, little is published regarding late noncardiac complications. This study aimed to determine the prevalence and risk factors for renal dysfunction among adults after TOF repair. For this study, 56 adult patients with complete repair of TOF were identified, and their charts were retrospectively reviewed. An estimated glomerular filtration rate (eGFR) for each patient was calculated using the Modification of Diet in Renal Disease formula (MDRD). Using each patient's eGFR, he or she was classified into stages based on the National Kidney Foundation chronic kidney disease (CKD) staging. Clinical parameters were compared among patients with and those without renal dysfunction to identify risk factors for renal impairment. The median estimated eGFR rate for the cohort was 78 ml/min/1.73 m(2). Based on the National Kidney Foundation CKD staging system, 54 % of the patients had at least stage 2 chronic renal disease. The risk factors identified were hypertension (p < 0.01), type 2 diabetes mellitus (p < 0.05), longer follow-up evaluation (p < 0.005), older age at complete repair (p < 0.05), and use of daily diuretics (p < 0.05). After repair of TOF, renal dysfunction is common at late follow-up evaluation. The study findings show the importance of routine assessment of renal function and the need to limit or avoid future episodes of acute kidney injury in this at-risk population.

Hypergraph coloring complexes.

The aim of this paper is to generalize the notion of the coloring complex of a graph to hypergraphs. We present three different interpretations of those complexes-a purely combinatorial one and two geometric ones. It is shown, that most of the properties, which are known to be true for coloring complexes of graphs, break down in this more general setting, e.g., Cohen-Macaulayness and partitionability. Nevertheless, we are able to provide bounds for the [Formula: see text]- and [Formula: see text]-vectors of those complexes which yield new bounds on chromatic polynomials of hypergraphs. Moreover, though it is proven that the coloring complex of a hypergraph has a wedge decomposition, we provide an example showing that in general this decomposition is not homotopy equivalent to a wedge of spheres. In addition, we can completely characterize those hypergraphs whose coloring complex is connected.

Urinary exosomal expression of activator of G protein signaling 3 in polycystic kidney disease.

OBJECTIVE: PKD is a genetic disease that is characterized by abnormally proliferative epithelial cells in the kidney and liver. Urinary exosomes have been previously examined as a source of unique proteins that may be used to diagnose and monitor the progression of PKD. Previous studies by our group have shown that AGS3, which is a receptor-independent regulator G-proteins, was markedly upregulated in RTECs during kidney injury including PKD. In this study, our goal was to determine whether AGS3 could be measured in exosomes using animals and humans with PKD. RESULTS: In our study, urinary exosomes were isolated from PCK rats and the control Sprague-Dawley (SD) rats. AGS3 expression was significantly increased (P < 0.05) in PKD versus SD rats at 16 weeks of age. This increase was detectable in a time-dependent manner from 8 weeks of age and peaked at ~ 16-20 weeks (length of study). Similarly, in exosomes from human urine samples with PKD, AGS3 expression was significantly increased (P < 0.05) compared to healthy human controls where AGS3 was largely undetectable. In conclusion, the detection of AGS3 in urinary exosomes may be a novel biomarker for PKD, and provide new insight into the biology of tubular epithelial cell function during cystic disease progression.

Urinary interleukin-18 and urinary neutrophil gelatinase-associated lipocalin predict acute kidney injury following pulmonary valve replacement prior to serum creatinine.

BACKGROUND: It is becoming increasingly recognized that manifestations of congenital heart disease (CHD) extend beyond the cardiovascular system. The factors contributing to renal dysfunction in patients with CHD are multifactorial, with acute kidney injury (AKI) at time of cardiac surgery playing a major role. AKI is often diagnosed based on changes in serum creatinine and estimated glomerular filtration rate (eGFR). Such measurements are often late and imprecise. Recent data indicate that urinary biomarkers interleukin-18 (IL-18) and neutrophil gelatinase-associated lipocalin (NGAL) are earlier markers of AKI. We sought to determine the efficacy of urinary IL-18 and NGAL for detecting early AKI in patients undergoing surgical pulmonary valve replacement (PVR). METHODS: Twenty patients presenting for surgical PVR with a history of previous repair of a conotruncal anomaly were enrolled. Preoperative clinical data were measured and urine samples and serum creatinine were collected at 6, 12, 24, and 72 hours post bypass. Urine was evaluated for NGAL and IL-18. AKI was determined using the Risk, Injury, Failure, Loss and End Stage Renal Disease (RIFLE) classification system. RESULTS: Using the RIFLE classification system, seven patients (35%) were found to have AKI defined as a drop in the eGFR or an increase in serum creatinine. All seven patients with AKI had marked increase from preoperative baseline in urine IL-18 (sixfold) and NGAL (26-fold). Using NGAL and IL-18, AKI was detected at 6 hours postoperatively, resulting in AKI being identified 12-36 hours prior to detection by conventional methods. No preoperative predictors for AKI were identified. CONCLUSION: Both NGAL and IL-18 are early predictive biomarkers of AKI, and both increase in tandem after surgical PVR. Importantly, both rise before an increase in creatinine or a decrease in eGFR is present. Monitoring both biomarkers may allow for earlier detection and subsequent interventions to prevent AKI at time of surgery for CHD.

BK virus nephritis after renal transplantation.

BK virus nephritis is an increasing problem and is posing a threat to improving renal transplant graft survival. The pathogenesis of this condition remains to be investigated. Higher prevalence of BK virus infection in recent years has been correlated with declining acute rejection rates and the use of potent immunosuppressive agents. Patients with this infection usually have asymptomatic viremia and/or nephritis with or without worsening of renal function. The diagnosis of this disease is based on detecting the virus or its effects in urine, blood, and renal tissue. In the past, approximately 30 to 60% of patients with BK virus nephritis developed graft failure. In recent years, the combination of early detection, prompt diagnosis, and therapies including preventive measures have resulted in better outcomes.

Outcomes in patients with chronic kidney disease referred late to nephrologists: a meta-analysis.

PURPOSE: The study purpose was to compare differences in mortality and the duration of hospitalization in patients with chronic kidney disease who are referred early versus late to nephrologists. METHODS: We searched English-language literature from 1980 through December 2005, along with national conference proceedings, the Web of Science Citation Index, and reference lists of all included studies. Twenty-two studies with a total sample size of 12,749 met inclusion criteria. RESULTS: There was significantly increased overall mortality in the late referral group as compared with the early referral group (relative risk 1.99; 95% confidence interval [CI], 1.66 to 2.39, P <.0001). The duration of hospital stay, at the time of initiation of renal replacement therapy, was greater in the late referred group by an average of 12 days (95% CI, 8.0 to 16.1, P=.0007). Significant heterogeneity was detected for both outcomes. CONCLUSION: Timing of referral emerged to be a significant factor impacting homogeneity in the mortality outcome. Our results suggest significantly higher mortality and increased early hospitalization of chronic kidney disease subjects referred late to nephrologists as compared with earlier referred subjects.