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New SOFA version could streamline outcomes research



A simplified version of the Sequential Organ Failure Assessment (SOFA) criteria, known as eSOFA, has the potential to make it easier for hospitals to benchmark sepsis outcomes and quality of care, and could propel new sepsis research. The new method replaces some of SOFA’s more subjective criteria with objective measures.

Dr. Chanu Rhee of Harvard Medical School, Boston

Dr. Chanu Rhee

eSOFA relies on electronic health records to reduce reliance on administrative records, which suffer from cross-hospital variability in diagnosis and coding practices, as well as changes in these practices over time. The diagnosis of sepsis itself is also highly subjective. Instead, eSOFA determines dysfunction in six organ systems, indicated by use of vasopressors and mechanical ventilation, and the presence of abnormal laboratory values.

“The SOFA score includes measures like the Glasgow Coma Scale, which undoubtedly at the bedside is a very important clinical sign, but when trying to implement something that is objective for purposes of retrospective case counting and standardization, it can be problematic. The measures we chose [for eSOFA] are concrete, important maneuvers that were initiated by clinicians,” Chanu Rhee, MD, said in an interview.

Dr. Rhee is assistant professor of population medicine at Harvard Medical School and Brigham and Women’s Hospital, Boston. He presented the results of the study at the Critical Care Congress sponsored by the Society of Critical Care Medicine, and the work was simultaneously published online in Critical Care Medicine.

Key elements of SOFA that pose challenges for administrative data include: PaO2/FiO2, which are not routinely measured, and can be difficult to assign to arterial or venous samples; inconsistency in blood pressure and transient increases in vasopressor dose; the subjectivity of the Glasgow Coma Scale, which is also difficult to assess in sedated patients; and inconsistent urine output.

eSOFA introduced new measures for various organ functions, including cardiovascular (vasopressor initiation), pulmonary (mechanical ventilation initiation), renal (doubling of creatinine levels or a 50% or greater decrease in estimated glomerular filtration rate, compared with baseline), hepatic (bilirubin levels greater than or equal to 2.0 mg/dL and at least doubled from baseline), coagulation (platelet count less than 100 cells/mcL and at least a 50% decrease from a baseline of at least 100 cells/mcL), and neurological (lactate greater than or equal to 2.0 mmol/L).

“[eSOFA] opens a window into inter-facility comparisons that has not been possible to do. It’s really critical to ask, ‘How am I doing compared to my peer institutions?’ If you’re doing worse, you can look at the whole spectrum of things to try to drive improvements in care,” said Dr. Rhee.

The new tool isn’t just limited to quality improvement research. Shaeesta Khan, MD, assistant professor of critical care medicine at Geisinger Medical Center,Danville, Pa., has found eSOFA to be useful in her research into how genetic polymorphisms play a role in sepsis outcomes. Geisinger has a large population of patients with completed whole genome sequencing, and Dr. Khan began by trying to glean sepsis outcomes from administrative data.

“I explained SOFA scores to our data broker, and he pulled up 3,000 patients and gave everybody a SOFA score based on the algorithm he created, and it was all over the chart. Once I started doing chart review and phenotype verification, it was just a nightmare,” Dr. Khan said in an interview.

After struggling with the project, one of her mentors put her in touch with one of Dr. Rhee’s colleagues, and she asked the data broker to modify the eSOFA algorithm to fit her specific criteria. “It was a blessing,” she said.

Now, she has data from 5,000 patients with sepsis and sequenced DNA, and can begin comparing outcomes and genetic variants. About 20 candidate genes for sepsis outcomes have been identified to date, but she has a particular interest in PCSK9, which is an innate immune system regulator. She hopes to present results at CCC49 in 2020.


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