Inequities of ICU care for First Nations

RISK of death and 12-month mortality among critically ill patients admitted to the intensive care unit are higher for Indigenous than non-Indigenous people, according to research published today by the MJA.

“Rates of ill-health are higher and life expectancy lower for indigenous peoples than for other people in many countries,” wrote the researchers, led by Dr Paul Secombe, an intensivist at Alice Springs Hospital and Adjunct Lecturer at Monash University.

“Further, critical illness is associated with significant morbidity, and mortality following intensive care unit (ICU) care is higher than the general population death rate.

“However, few investigations of longer term outcomes have been published, particularly for critically ill Aboriginal and Torres Strait Islander (Indigenous) Australians.”

Secombe and colleagues set out to compare longer term (12-month) mortality outcomes for Indigenous and non-Indigenous people admitted to ICUs in Australia. They analysed data from all admissions of adults (16 years or older) to Australian ICUs from 1 January 2017 to 31 December 2019, recorded in the Australian and New Zealand Intensive Care Society (ANZICS) Adult Patient Database (APD).

“The APD recorded 330 712 eligible ICU admissions during 2017–2019 (65% of all ICU admissions registered), of which 11 322 were of Indigenous people (3.4%),” they reported.

“Median age at admission was lower for Indigenous patients (51.2 [IQR, 36.7–63.6] years) than for non-Indigenous patients (66.5 [IQR, 52.7–76.1] years). Unadjusted mortality risk was similar for Indigenous and non-Indigenous patients (hazard ratio, 1.01; 95% CI, 0.97–1.06), but was higher for Indigenous patients after adjusting for age, admission diagnosis, illness severity, hospital type, jurisdiction, remoteness and socio-economic status (adjusted hazard ratio, 1.20; 95% CI, 1.14–1.27). Twelve-month mortality was higher for Indigenous than non-Indigenous patients (adjusted odds ratio, 1.24; 95% CI, 1.16–1.33).

“Hospital mortality does not include the full mortality burden of critical illness,” Secombe and colleagues wrote.

“After taking the lower median age of Indigenous ICU patients into account, their mortality outcomes are significantly poorer than for non-Indigenous patients.”

The authors concluded that their findings suggested that critical illness may contribute to earlier death among Indigenous Australians, and “consequently to lower life expectancy”.

“It is likely that the difference is less directly attributable to the ICU admission than to a complex interplay between pre- and post-hospitalisation factors, socio-economic disadvantage, remoteness, and chronic disease trajectory,” they wrote.

“Primary and public health interventions for preventing and managing chronic disease could reduce the incidence of early death.

“Although in-hospital mortality is similar for Indigenous and non-Indigenous ICU patients, longer term risk of death and 12-month mortality are each higher for Indigenous than non-Indigenous people.

“Further, as the median age of Indigenous patients is about 15 years lower than for non-Indigenous ICU patients, the differences for critically ill Indigenous people are even more marked after adjusting for age and other factors.”

Changes to bat habitats facilitate Hendra virus spillover risk

Research from Griffith University, published in Nature, examined 25 years of data on land-use change, bat behaviour, and spillover of Hendra virus from bats to horses in subtropical Australia and revealed that human activities are causing bats to adopt behaviours previously linked to short-term nutritional stress, and that this change in behaviour is increasing risk of Hendra virus spillover. Previous correlational studies associate spillover with broad-scale habitat destruction and encroachment of people into natural landscapes, increasing opportunities for contact between wildlife, domestic animals and people.  The current study highlights that habitat destruction, agriculture and people were important in broadly determining where risk was high – but not simply because encroachment directly led to increased opportunities for contact as previously assumed.  Instead, the researchers found that flying foxes responded to land-use change by shifting their distribution and invoking behaviours that they would normally use to avoid climate-driven starvation associated with El Niño events, such as feeding on introduced plants in horse paddocks. This was causing them to shift into agricultural areas that did not provide native food over winter.  Extensive clearing of forests that flower in winter has led to a reduction in the number of years when abundant flowering occurs, reducing the reliability of this natural source of protection and increasing the risk of spillovers. “We propose that restoration of this critical habitat will restore functioning ecosystems, improve the health of flying foxes, reduce their reliance on urban and agricultural areas, and protect horses and people against spillover of Hendra and other viruses,” said lead author Dr Peggy Eby, from University of New South Wales.

Nasal vaccine strategy could improve COVID-19 protection

Researchers from the Centenary Institute and the University of Sydney have developed a new nasal vaccination strategy that induces potent lung immunity and protection against the SARS-CoV-2 coronavirus. The approach has been tested successfully in mice and has the potential to be a powerful tool for enhancing protection against COVID-19 infection and minimising ongoing viral spread. Made up of the SARS-CoV-2 spike protein and an adjuvant called Pam2Cys (a molecule that helps stimulate a stronger immune response in the body), that was developed by Professor Richard Payne, NHMRC Investigator in the University of Sydney’s Faculty of Science, the new vaccine was delivered via simply breathing in through the nose. It prompted substantial levels of neutralising antibodies and increased T-cell responses in the lungs and airways of the mice that were tested. In the mice study, the new vaccine was delivered nasally, making its way through the respiratory tract, adhering to the tissues of the nasal cavity, airways and lungs. Testing showed the generation of high levels of protective antibodies in the airways and increased T-cell responses in the lungs (T-cells help destroy SARS-CoV-2 infected cells). Significantly, none of the vaccinated mice became infected with COVID-19. “Our vaccine differs from most current COVID-19 vaccines in that it enables generation of an immune response directly in those areas of the body that are likely to be the first point of contact for the virus – the nose, airway and lungs. This may help explain the vaccine’s effectiveness,” said lead author Dr Anneliese Ashhurst, a research fellow at the University of Sydney and the Centenary Institute. The study was published in Nature Communications.

Subscribe to the free InSight+ weekly newsletter here. It is available to all readers, not just registered medical practitioners.