Studies look at how COVID-19 mortality varied by hospital, over time

Hospital strain seems to be a significant factor in patients' mortality from COVID-19, according to a study analyzing deaths among ICU patients by hospital and another comparing March and April 2020 outcomes to those later in the year.


Two recent studies looked at the variation in mortality rates from COVID-19 and identified some possible explanations.

The first study, published by the American Journal of Critical Care Medicine on April 23, analyzed variation in COVID-19 mortality among 4,019 U.S. ICU patients. It found that mortality rates ranged by hospital from 0% to 82%. However, the variation was significantly attenuated after adjustment for patient- and hospital-level factors, with the greatest changes occurring with adjustment for acute physiology, socioeconomic status, and critical care resource strain. The authors calculated relative contributions to mortality risk: the patient's acute physiology (49%), demographics and comorbidities (20%), socioeconomic status (12%), strain (9%), hospital quality (8%), and treatments (3%). “Our results help explain the wide variation in published mortality rates for critically ill COVID-19 patients and quantify how different factors contribute to an individual patient's mortality,” the authors said. “We found that hospital socioeconomic status, physiology, and hospital strain were the most important factors explaining this variability, while treatments provided to patients contributed least.”

The other study, published by JAMA Network Open on May 3, looked at changes in inpatient mortality from COVID-19 over time. The registry-based retrospective study included 20,736 patients admitted with COVID-19 to 107 acute care hospitals in 31 states from March through November 2020. The overall inpatient mortality rate was 15.8%, but it varied from 19.1% in March and April to 11.9% in May and June to 11.0% in July and August to 10.8% in September through November. The difference in mortality rates between the months of March and April and later months remained significant even after adjustment for patients' age, sex, medical history, and COVID-19 disease severity. The authors concluded that the reduction in inpatient mortality did not appear to be associated with changes in the characteristics of patients being admitted but they did note improvements in treatment over the study period such as glucocorticoids and high-flow nasal oxygen. “Extremely high hospital census or rapid implementation of new isolation and personal protection procedures may have adversely impacted patient outcomes in locations with very high rates of COVID-19 in March and April,” they wrote. “There is an urgent need to identify, share, and implement best practices for hospital care to prevent in-hospital mortality rates from increasing again.”

In other news of the pandemic, internal medicine residencies saw a significant increase in applicants in 2021, according to a research letter published by JAMA Network Open on April 28. The number of applicants increased every year from 2016 to 2021, but the annual increase from 2020 to 2021 (from 23,121 to 24,509 applicants; 6.0% increase) was more than twice that in any prior year studied. From 2020 to 2021, the number of applicants increased substantially for 10 fellowship programs, with the greatest increases in allergy/immunology (24.0%), hospice/palliative care medicine (20.5%), and infectious diseases (17.0%). The mean number of applications submitted per applicant has also increased annually, from 57.8 applications submitted per applicant in 2016 to 71.8 applications in 2021, but saw a particular bump from 2020 to 2021 (7.1 additional applications). “This trend may lead to a more diverse applicant pool; however, there are also potential negative consequences, such as added time for programs to review applications and congestion in the already labor- and time-intensive recruitment process,” the authors said.