The impact of inpatient bed capacity on length of stay

Objective

Large reductions in inpatient length of stay and inpatient bed supply have occurred across health systems in recent years. However, the direction of causation between length of stay and bed supply is often overlooked. This study examines the impact of changes to inpatient bed supply, as a result of recession-induced healthcare expenditure changes, on emergency inpatient length of stay in Ireland between 2010 and 2015.

Study design

We analyse all public hospital emergency inpatient discharges in Ireland from 2010 to 2015 using the administrative Hospital In-Patient Enquiry dataset. We use changes to inpatient bed supply across hospitals over time to examine the impact of bed supply on length of stay. Linear, negative binomial, and hospital–month-level fixed effects models are estimated.

Results

U-shaped trends are observed for both average length of stay and inpatient bed supply between 2010 and 2015. A consistently large positive relationship is found between bed supply and length of stay across all regression analyses. Between 2010 and 2012 while length of stay fell by 6.4%, our analyses estimate that approximately 42% (2.7% points) of this reduction was associated with declines in bed supply.

Conclusion

Changes in emergency inpatient length of stay in Ireland between 2010 and 2015 were closely related to changes in bed supply during those years. The use of length of stay as an efficiency measure should be understood in the contextual basis of other health system changes. Lower length of stay may be indicative of the lack of resources or available bed supply as opposed to reduced demand for care or the shifting of care to other settings.

     

Hepatitis B virus-like particles expressing Plasmodium falciparum epitopes induce complement-fixing antibodies against the circumsporozoite protein

The repetitive structure of compact virus-like particles (VLPs) provides high density displays of antigenic sequences, which trigger key parts of the immune system. The hepatitis B virus (HBV) and human papilloma virus (HPV) vaccines exploit the assembly competence of structural proteins, which are the effective immunogenic components of the prophylactic HBV and HPV vaccines, respectively. To optimize vaccine designs and to promote immune responses against protective epitopes, the “Asp-Ala-Asp-Pro” (NANP)-repeat from the Plasmodium falciparum circumsporozoite protein (CSP) was expressed within the exposed, main antigenic site of the small HBV envelope protein (HBsAgS); this differs from the RTS,S vaccine, in which CSP epitopes are fused to the N-terminus of HBsAgS. The chimeric HBsAgS proteins are assembly competent, produce VLPs, and provide a high antigenic density of the NANP repeat sequence. Chimeric VLPs with four or nine NANP-repeats (NANP4 and NANP9, respectively) were expressed in mammalian cells, the HBsAgS- and CSP-specific antigenicity of the VLPs was determined, and the immunogenicity of the VLPs assessed in relation to the induction of anti-HBsAgS and anti-CSP antibody responses. The chimeric VLPs induced high anti-CSP titres in BALB/c mice independent of the number of the NANP repeats. However, the number of NANP repeats influenced the activity of vaccine-induced antibodies measured by complement fixation to CSP, one of the proposed effector mechanisms for Plasmodium neutralization in vivo. Sera from mice immunized with VLPs containing nine NANP repeats performed better in the complement fixation assay than the group with four NANP repeats. The effect of the epitope-specific density on the antibody quality may instruct VLP platform designs to optimize immunological outcomes and vaccine efficacy.     

Predicting the initial spread of novel Asian origin influenza A viruses in the continental USA by wild waterfowl

Using data on waterfowl band recoveries, we identified spatially explicit hotspots of concentrated waterfowl movement to predict occurrence and spatial spread of a novel influenza A virus (clade 2.3.4.4) introduced from Asia by waterfowl from an initial outbreak in North America in November 2014. In response to the outbreak, the hotspots of waterfowl movement were used to help guide sampling for clade 2.3.4.4 viruses in waterfowl as an early warning for the US poultry industry during the outbreak . After surveillance sampling of waterfowl, we tested whether there was greater detection of clade 2.3.4.4 viruses inside hotspots. We found that hotspots defined using kernel density estimates of waterfowl band recoveries worked well in predicting areas with higher prevalence of the viruses in waterfowl. This approach exemplifies the value of ecological knowledge in predicting risk to agricultural security.     

Fluorescence imaging of dental restorations using the VistaCam intra-oral camera

Optical fluorescence imaging methods have a range of forensic applications. The VistaCam system (Dürr Dental) is an existing intra-oral fluorescence camera, which was designed to aid detection of dental caries using 405 nm wavelength light generated by light emitting diodes (LEDs). This study assessed whether this fluorescence imaging device could also be used to recognize dental restorative materials, which is essential for accurate dental charting of deceased persons who are unidentified. The effect of body fluids (saliva and blood) on performance was also assessed. The VistaCam was used on the bench to assess 55 extracted human teeth with restorations, and samples of restorative materials. Readings were first taken in the moist state and then after the application of human saliva or venous blood. Fluorescence scores were compared using one-way ANOVA. Human enamel gave lower fluorescence than restorations. Different tooth-coloured restorative materials gave similar strong fluorescence scores, without statistically significant differences between them. Fluorescence scores were not affected by the presence of ambient fluids (saliva or blood). Using violet 405 nm light to elicit fluorescence may aid in the recognition of dental restorative materials.