Rates of readmission and death associated with leaving hospital against medical advice: a population-based study

Background:

Leaving hospital against medical advice may have adverse consequences. Previous studies have been limited by evaluating specific types of patients, small sample sizes and incomplete determination of outcomes. We hypothesized that leaving hospital against medical advice would be associated with increases in subsequent readmission and death.

Methods:

In a population-based analysis involving all adults admitted to hospital and discharged alive in Manitoba from Apr. 1, 1990, to Feb. 28, 2009, we evaluated all-cause 90-day mortality and 30-day hospital readmission. We used multivariable regression, adjusted for age, sex, socioeconomic status, year of hospital admission, patient comorbidities, hospital diagnosis, past frequency of admission to hospital, having previously left hospital against medical advice and data clustering (patients with multiple admissions). For readmission, we assessed both between-person and within-person effects of leaving hospital against medical advice.

Results:

Leaving against medical advice occurred in 21 417 of 1 916 104 index hospital admissions (1.1%), and was associated with higher adjusted rates of 90-day mortality (odds ratio [OR] 2.51, 95% confidence interval [CI] 2.18–2.89), and 30-day hospital readmission (within-person OR 2.10, CI 1.99–2.21; between-person OR 3.04, CI 2.79–3.30). In our additional analyses, elevated rates of readmission and death associated with leaving against medical advice were manifest within 1 week and persisted for at least 180 days after discharge.

Interpretation:

Adults who left the hospital against medical advice had higher rates of hospital readmission and death. The persistence of these effects suggests that they are not solely a result of incomplete treatment of acute illness. Interventions aimed at reducing these effects may need to include longitudinal interventions extending beyond admission to hospital.Patients leaving hospital against medical advice have been discussed in the medical literature for more than 50 years.¹ Reported to occur in 1%–2% of patients in general hospitals,^2,3 the numbers are large; in the United States, 368 000 patients left against medical advice in 2007,³ and rates higher than 10% have been documented in certain subgroups, including Canadian patients with HIV and predominantly poor residents of inner city areas.^4,5 The main concern over leaving hospital against medical advice is that it may increase morbidity or mortality. Previous studies attempting to assess this effect^2,4–13 have all been restricted to specific types of patients, and most studies were limited by small sample sizes and incomplete determination of outcomes. In this study, we used data that avoided these limitations to test the hypothesis that patients who leave hospital against medical advice have higher rates of hospital readmission and death.     

Biofilm formation in an experimental water distribution system: the contamination of non-touch sensor taps and the implication for healthcare

Hospital tap water is a recognised source of Pseudomonas aeruginosa. UK guidance documents recommend measures to control/minimise the risk of P. aeruginosa in augmented care units but these are based on limited scientific evidence. An experimental water distribution system was designed to investigate colonisation of hospital tap components. P. aeruginosa was injected into 27 individual tap ‘assemblies’. Taps were subsequently flushed twice daily and contamination levels monitored over two years. Tap assemblies were systematically dismantled and assessed microbiologically and the effect of removing potentially contaminated components was determined. P. aeruginosa was repeatedly recovered from the tap water at levels above the augmented care alert level. The organism was recovered from all dismantled solenoid valves with colonisation of the ethylene propylene diene monomer (EPDM) diaphragm confirmed by microscopy. Removing the solenoid valves reduced P. aeruginosa counts in the water to below detectable levels. This effect was immediate and sustained, implicating the solenoid diaphragm as the primary contamination source.     

An extraction free modified o-phthalaldehyde assay for quantifying residual protein and microbial biofilms on surfaces

Abstract

Biological contamination of surfaces in industry and healthcare is an important vector of disease transmission. Current assays for detecting surface-adherent contamination require extraction of biological soil. However, physical inaccessibility or poor solubility may limit recovery. Here, how the o-phthalaldehyde (OPA) protein assay can be modified to measure residual protein (modeled with bovine serum albumin) or biofilm on a surface without extraction is described. The assay limit of detection (LOD) for protein was 1.6 µg cm^?2. The detection threshold for Staphylococcus epidermis biofilm was 117 µg cm^?2. The clinical utility of the method was demonstrated for measurements taken from clinically used endoscopes. Since this method is more sensitive than extraction-based testing, clinical results should not be compared with conventional benchmarks. By enabling direct detection and quantification of soils in complex or hard-to-reach areas, this method has potential to improve the margin of safety in medical and industrial cleaning processes.     

Breeding distribution,population size and conservation of the Greyheaded Gull Larus cirrocephalus in southern Africa

Brooke, R.K., Allan, D.G., Cooper, J., Cyrus, D.P., Dean, W.R.J., Dyer, B.M., Martin, A.P. & Taylor, R.H. 1999. Breeding distribution, population size and conservation of the Greyheaded Gull Larus cirrocephalus in southern Africa. Ostrich 70 (3&4): 157–163.

The Greyheaded Gull Larus cirrocephalus occurs throughout southern Africa, both coastally and inland, and has bred at one time or another at 67 known localities since the 1860s. Most of these sites have been occupied by small numbers of birds, even single pairs, and for only one or a few years. The two principal breeding areas are the East Rand in Gauteng and Lake St Lucia in KwaZulu-Natal, both in South Africa. The next most important sites are Walvis Bay, Namibia and Lake Ngami, Botswana. The total southern African breeding population is estimated as about 2000 pairs. The Greyheaded Gull is not a threatened species in southern Africa, with 27 breeding sites supporting more than half the breeding population within formally conserved areas.     

Detection of Proton Movement Directly across Viral Membranes To Identify Novel Influenza Virus M2 Inhibitors

The influenza virus M2 protein is a well-validated yet underexploited proton-selective ion channel essential for influenza virus infectivity. Because M2 is a toxic viral ion channel, existing M2 inhibitors have been discovered through live virus inhibition or medicinal chemistry rather than M2-targeted high-throughput screening (HTS), and direct measurement of its activity has been limited to live cells or reconstituted lipid bilayers. Here, we describe a cell-free ion channel assay in which M2 ion channels are incorporated into virus-like particles (VLPs) and proton conductance is measured directly across the viral lipid bilayer, detecting changes in membrane potential, ion permeability, and ion channel function. Using this approach in high-throughput screening of over 100,000 compounds, we identified 19 M2-specific inhibitors, including two novel chemical scaffolds that inhibit both M2 function and influenza virus infectivity. Counterscreening for nonspecific disruption of viral bilayer ion permeability also identified a broad-spectrum antiviral compound that acts by disrupting the integrity of the viral membrane. In addition to its application to M2 and potentially other ion channels, this technology enables direct measurement of the electrochemical and biophysical characteristics of viral membranes.     

Naturally Acquired Picornavirus Infections in Primates at the Dhaka Zoo

The conditions in densely populated Bangladesh favor picornavirus transmission, resulting in a high rate of infection in the human population. Data suggest that nonhuman primates (NHP) may play a role in the maintenance and transmission of diverse picornaviruses in Bangladesh. At the Dhaka Zoo, multiple NHP species are caged in close proximity. Their proximity to other species and to humans, both zoo workers and visitors, provides the potential for cross-species transmission. To investigate possible interspecies and intraspecies transmission of picornaviruses among NHP, we collected fecal specimens from nine NHP taxa at the Dhaka Zoo at three time points, August 2007, January 2008, and June 2008. Specimens were screened using real-time PCR for the genera Enterovirus, Parechovirus, and Sapelovirus, and positive samples were typed by VP1 sequencing. Fifty-two picornaviruses comprising 10 distinct serotypes were detected in 83 fecal samples. Four of these serotypes, simian virus 19 (SV19), baboon enterovirus (BaEV), enterovirus 112 (EV112), and EV115, have been solely associated with infection in NHP. EV112, EV115, and SV19 accounted for 88% of all picornaviruses detected. Over 80% of samples from cages housing rhesus macaques, olive baboons, or hamadryas baboons were positive for a picornavirus, while no picornaviruses were detected in samples from capped langurs or vervet monkeys. In contrast to our findings among synanthropic NHP in Bangladesh where 100% of the picornaviruses detected were of human serotypes, in the zoo population, only 15% of picornaviruses detected in NHP were of human origin. Specific serotypes tended to persist over time, suggesting either persistent infection of individuals or cycles of reinfection.     

Molecular details of membrane fluidity changes during apoptosis and relationship to phospholipase A2 activity

Secretory phospholipase A₂ exhibits much greater activity toward apoptotic versus healthy cells. Various plasma membrane changes responsible for this phenomenon have been proposed, including biophysical alterations described as “membrane fluidity” and “order.” Understanding of these membrane perturbations was refined by applying studies with model membranes to fluorescence measurements during thapsigargin-induced apoptosis of S49 cells using probes specific for the plasma membrane: Patman and trimethylammonium-diphenylhexatriene. Alterations in emission properties of these probes corresponded with enhanced susceptibility of the cells to hydrolysis by secretory phospholipase A₂. By applying a quantitative model, additional information was extracted from the kinetics of Patman equilibration with the membrane. Taken together, these data suggested that the phospholipids of apoptotic membranes display greater spacing between adjacent headgroups, reduced interactions between neighboring lipid tails, and increased penetration of water among the heads. The phase transition of artificial bilayers was used to calibrate quantitatively the relationship between probe fluorescence and the energy of interlipid interactions. This analysis was applied to results from apoptotic cells to estimate the frequency with which phospholipids protrude sufficiently at the membrane surface to enter the enzyme's active site. The data suggested that this frequency increases 50–100-fold as membranes become susceptible to hydrolysis during apoptosis.     

Speciation of antimony in natural waters : the determination of Sb(III) and Sb(V) by continuous flow hydride generation-atomic absorption spectrometry

Abstract

A new procedure for the speciation of dissolved antimony is described. This makes use of complexation with citrate to prevent, preferentially, the formation of hydride from Sb(V) and allow the selective determination of Sb(III) to be made by continuous flow hydride generation - atomic absorption spectrometry. When the citric acid (12% m/V) is replaced by potassium iodide (3% m/V), total antimony is determined and the concentration of Sb(V) can be obtained by difference. The determination of the antimony species is dominated in this new procedure by the complexation of Sb(V) with citrate and the effect of pH is limited to a minor, re-inforcing role. This permits acidification to be made with hydrochloric acid. The principal interfering species in the determination of total antimony and Sb(III) is Fe³⁺, with Fe²⁺, Cu²⁺ and Ni²⁺ showing lesser effects on Sb(III). The technique is applied successfully to synthetic mixtures and to natural waters from the environment of a disused antimony mine.

The characteristic concentration obtained for antimony was 0.7 ng mL^–1 and the detection limit 1 ng mL^–1.     

Bioinformatic Identification and Analysis of Extensins in the Plant Kingdom

Extensins (EXTs) are a family of plant cell wall hydroxyproline-rich glycoproteins (HRGPs) that are implicated to play important roles in plant growth, development, and defense. Structurally, EXTs are characterized by the repeated occurrence of serine (Ser) followed by three to five prolines (Pro) residues, which are hydroxylated as hydroxyproline (Hyp) and glycosylated. Some EXTs have Tyrosine (Tyr)-X-Tyr (where X can be any amino acid) motifs that are responsible for intramolecular or intermolecular cross-linkings. EXTs can be divided into several classes: classical EXTs, short EXTs, leucine-rich repeat extensins (LRXs), proline-rich extensin-like receptor kinases (PERKs), formin-homolog EXTs (FH EXTs), chimeric EXTs, and long chimeric EXTs. To guide future research on the EXTs and understand evolutionary history of EXTs in the plant kingdom, a bioinformatics study was conducted to identify and classify EXTs from 16 fully sequenced plant genomes, including Ostreococcus lucimarinus, Chlamydomonas reinhardtii, Volvox carteri, Klebsormidium flaccidum, Physcomitrella patens, Selaginella moellendorffii, Pinus taeda, Picea abies, Brachypodium distachyon, Zea mays, Oryza sativa, Glycine max, Medicago truncatula, Brassica rapa, Solanum lycopersicum, and Solanum tuberosum, to supplement data previously obtained from Arabidopsis thaliana and Populus trichocarpa. A total of 758 EXTs were newly identified, including 87 classical EXTs, 97 short EXTs, 61 LRXs, 75 PERKs, 54 FH EXTs, 38 long chimeric EXTs, and 346 other chimeric EXTs. Several notable findings were made: (1) classical EXTs were likely derived after the terrestrialization of plants; (2) LRXs, PERKs, and FHs were derived earlier than classical EXTs; (3) monocots have few classical EXTs; (4) Eudicots have the greatest number of classical EXTs and Tyr-X-Tyr cross-linking motifs are predominantly in classical EXTs; (5) green algae have no classical EXTs but have a number of long chimeric EXTs that are absent in embryophytes. Furthermore, phylogenetic analysis was conducted of LRXs, PERKs and FH EXTs, which shed light on the evolution of three EXT classes.