A critical analysis of discovery health's claims-based risk adjustment of mortality rates in South African private sector hospitals

In 2019, Discovery Health published a risk adjustment model to determine standardised mortality rates across South African private hospital systems, with the aim of contributing towards quality improvement in the private healthcare sector. However, the model suffers from limitations due to its design and its reliance on administrative data. The publication's aim of facilitating transparency is unfortunately undermined by shortcomings in reporting. When designing a risk prediction model, patient-proximate variables with a sound theoretical or proven association with the outcome of interest should be used. The addition of key condition-specific clinical data points at the time of hospital admission will dramatically improve model performance. Performance could be further improved by using summary risk prediction scores such as the EUROSCORE II for coronary artery bypass graft surgery or the GRACE risk score for acute coronary syndrome. In general, model reporting should conform to published reporting standards, and attempts should be made to test model validity by using sensitivity analyses. In particular, the limitations of machine learning prediction models should be understood, and these models should be appropriately developed, evaluated and reported.

Transmission of respiratory viruses when using public ground transport: A rapid review to inform public health recommendations during the COVID-19 pandemic

In response to the COVID-19 pandemic, numerous countries worldwide declared national states of emergency and implemented interventions to minimise the risk of transmission among the public. Evidence was needed to inform strategies for limiting COVID-19 transmission on public transport. On 20 March 2020, we searched MEDLINE, CENTRAL, Web of Science and the World Health Organization's database of 'Global research on coronavirus disease (COVID-19)' to conduct a rapid review on interventions that reduce viral transmission on public ground transport. After screening 74 records, we identified 4 eligible studies. These studies suggest an increased risk of viral transmission with public transportation use that may be reduced with improved ventilation. International and national guidelines suggest the following strategies: keep the public informed, stay at home when sick, and minimise public transport use. Where use is unavoidable, environmental control, respiratory etiquette and hand hygiene are recommended, while a risk-based approach needs to guide the use of non-medical masks