Scale that measures organ dysfunction in critically ill patients is updated after nearly 30 years and incorporates modern technologies in intensive care medicine 

Recently published in JAMA and developed with the participation of researchers from the D’Or Institute for Research and Education (IDOR), the new Sequential Organ Failure Assessment 2 (SOFA-2) score updates one of the main tools used worldwide to assess the severity of patients admitted to Intensive Care Units (ICUs). The update revises thresholds, adds criteria, and integrates technologies that did not exist or were not widely used when the original SOFA was created in 1996. 

Dr. Jorge Salluh, researcher at IDOR and member of the study’s Coordinating Committee, led the project’s data and validation group. “This study was decisive in modifying the score because it brought together several important conditions. The first was a large number of specialists in intensive care, statistics, epidemiology, Big Data, and other areas. The second was the creation of a very robust methodology, so that the study was not based solely on expert opinion, but on in-depth research supported by multiple systematic reviews and meta-analyses using current data,” he states. 

Why update SOFA now 

Today, it would likely seem strange to navigate a car trip using a printed map from 30 years ago. Yet, in a way, that is what ICUs around the world had been doing until last week when it came to classifying the severity of critically ill patients on an international scale. 

SOFA is a daily score applied to ICU patients to assess the function of six body systems: brain, liver, kidney, hemostasis (related to coagulation), respiratory system, and cardiovascular system. Each system receives a score from 0 to 4, resulting in a total score ranging from 0 to 24. The higher the score, the more severe the clinical condition. 

With advances in intensive care medicine, new drugs, devices, and organ support strategies have dramatically changed the treatment of critically ill patients. The original SOFA, created before the widespread use of the internet, clearly did not keep pace with this evolution. 

The consequence was that patients with very different clinical conditions sometimes received similar scores, making it difficult to compare cases, follow clinical progression over time, and even build comparable scientific studies across countries and hospitals. 

How SOFA-2 was developed 

The creation of SOFA-2 had been under discussion among physicians and researchers for years, but its recent definition is the result of an international effort. More than 60 intensive care specialists participated in a structured collaborative process, identifying new classification needs and working toward global scientific consensus. 

Afterward, the score was tested in databases covering more than 1,300 ICUs across 9 countries between 2014 and 2023. In total, more than 3.3 million hospitalizations were analyzed—an extensive validation ensuring that SOFA-2 is applicable in different contexts, from highly equipped centers to resource-limited settings. 

Why did it take 30 years to update SOFA? 

Because SOFA-1 was simple to use and adopted worldwide, the update needed to be scientifically robust and globally applicable, which only became possible with current technologies and the large volume of data used in this study. 

“Various articles over recent years have pointed out the need to update the score, due to major developments in monitoring, diagnosis, and treatment of critically ill patients. However, updating an accessible and globally used scale is challenging, especially when the necessary tools were not yet available. In recent years, we have seen accelerated data integration thanks to artificial intelligence and Big Data, which provided the ideal conditions to reevaluate SOFA,” explains Dr. Jorge Salluh, who was part of the Steering Committee and led the data and validation group. 

In other words, updating SOFA-1 to SOFA-2 was not simply a matter of revising a catalog, but of creating a new system of classification that incorporates new technologies, devices, and drugs developed over three decades, and that functions in ICUs worldwide, from the smallest to the most advanced. 

What changes in clinical practice 

Although the same six organ systems are maintained, the way they are scored has been updated to reflect contemporary practice. 

Respiratory system:
Now incorporates modern support modalities, such as non-invasive ventilation and ECMO, a procedure that temporarily replaces lung function. Oxygenation thresholds have also been adjusted. 

Cardiovascular system:
In addition to doses of norepinephrine and epinephrine, the score now includes other vasopressors and mechanical circulatory support devices, allowing a more precise description of shock. 

Kidneys:
Beyond creatinine and urine output, the use of renal replacement therapy (dialysis) now receives scoring, including in chronic cases. 

Brain:
SOFA-2 introduces the detection of delirium, which often goes unnoticed but is a strong indicator of neurological dysfunction in ICUs. 

A new era for classifying critically ill patients 

The main purpose of SOFA-2 is not to independently predict mortality risk, but to provide a standardized and updated language for measuring organ dysfunction over time. This allows more consistent comparisons among teams, hospitals, studies, and countries. 

By updating one of its most widely used tools, intensive care medicine takes an important step toward aligning scientific knowledge, clinical practice, and emerging technologies. SOFA-2 reflects the current reality of ICUs and prepares the field for new research, protocols, and care policies. 

“An important highlight is that real-world data were analyzed—not information from controlled environments, but from the daily routine of ICUs in several countries with high, medium, and low income. We now have a very robust score. Everything that was not present in the original score is present today in SOFA-2, which we have just published,” Salluh emphasizes.