Sepsis Scoring Calculator: Assessing Organ Dysfunction with the SOFA Score

The SOFA score was developed following a consensus meeting in 1994 to objectively describe organ dysfunction over time in groups of patients or individuals. Although initially not designed to predict outcomes, many study teams later found it to be useful in predicting outcomes in various settings, including trauma and sepsis patients. ^[1]
Notably, certain sub-scores, particularly those assessing the respiratory and cardiovascular systems, were also found to be good predictors of mortality.^{[1], [2], [3]}

The task force that defined the SEPSIS-3 criteria noted in their papers that the qSOFA score was better at predicting in-hospital mortality than both the SOFA and the SIRS scores. They also preferred the score for being simple while also not compromising on specificity.^[4]
However, other study groups have mentioned that this score lacks the sensitivity needed for triaging septic patients or determining the need for intensive care. Nevertheless, when combined with the SIRS criteria, it can yield improved results. ^[5]

In one study assessing the utility of the SOFA score on trauma patients, it was significantly associated with mortality, particularly for patients admitted to the ICU. Some components of the score, such as the respiratory and cardiovascular sub-scores, were found to be useful predictors of mortality (non-survivors had an average respiratory score of 2.5 versus 1.6 for the survivors; almost 80% of people that had a cardiovascular score of 3-4 did not survive). ^[2]

The authors noted that current scores used to evaluate trauma severity, such as the APACHE score, RTS, and IIS, have limitations and are primarily focused on assessing mortality rather than guiding individual patient management (the prognostic value of depends on the quality of treatment, they meant to be used in study settings rather than guide the management process for individual patients; also, some components of these scores are difficult to assess, especially in a trauma setting).

They also noted that some treatments that might not decrease mortality rates might still be useful and effective in the long-term (on reducing morbidity and increasing the quality-of-life after the event) and prevous score were not as useful in assessing the performance of such procedures. They further highlighted the relative simplicity and comprehensive focus of the SOFA score, making it a valuable tool for investigating organ dysfunction in trauma patients. Additionally, the authors observed that the score provided persistent assessments, especially for non-survivors in the initial 10 days following admission, with a majority of deaths occurring within this period. ^{[3], [2]}

In one study, the presence of infection on admission in the ICU was associated with higher score for every organ assessed. Later after admission, the score was more likely to increase in non-survivors (44% vs 20%) and more likely to decrease in survivor patients (33% vs 21%). ^[3]

In another study focusing on patients admitted to the ICU, the authors found that initial and highest SOFA scores above 11 or mean scores over 5 corresponded to a mortality rate exceeding 80%. Patients with initial scores above 11 had a mortality rate over 90%. Between these SOFA values, the mean and highest score was better associated with mortality than the initial score or the delta between the scores. ^{[6], [9]} Furthermore, changes in the SOFA score within the first 96 hours were associated with varying mortality rates:

1. If for any reason, the score started increasing in the first 96 hours, these patients would come on to have a mortality of at least 50%.
2. If the score started decreasing in the first 2 days, the mortality rate was shown to be below 6%.
3. If the score didn't change, the mortality rate was around a third (37%), if the initial score was 2-7 and 60% if the score was 8-11. ^[6]

In conclusion, initial SOFA scores after ICU admission are highly associated with mortality risk and can serve as good predictors of outcomes. ^{[7], [8], [9]}

In summary, the SOFA score is a valuable tool for predicting mortality in various settings. It provides a good estimation of mortality, particularly when assessed repeatedly during a patient's hospital stay. The score assesses multiple organ systems, and some of the sub-scores still hold statistical significance, even when taken separately. Additionally, the score has been extensively studied and can provide insights into morbidity, making it useful for evaluating the success of different procedures.