The use of maximum SOFA score to quantify organ dysfunction/failure in intensive care. Results of a prospective, multicentre study

Objective: To evaluate the performance of total maximum sequential organ fa ilure assessment (SOFA) score and a derived measure, delta SOFA (total maxi mum SOFA score minus admission total SOFA) as a descriptor of multiple orga n dysfunctional/failure in intensive care. Design: Prospective, multicentre and multinational study. Setting: Forty intensive care units (ICUs) from Australia, Europe, North an d South America. Patients: Data on 1,449 patients, evaluated at admission and then consecuti vely every 24 h until ICU discharge (11,417 records) during May 1995. Exclu ded from data collection were all patients with a length of stay in the ICU less than 2 days following uncomplicated scheduled surgery. Main outcome measure: Survival status at ICU discharge. Interventions:The collection of raw data necessary for the computation of a SOFA score on admission and then every 24 h, and basic demographic and cli nical statistics. Measurements and main results: Mean total maximum SOFA score presented a ve ry good correlation to ICU outcome, with mortality rates ranging from 3.2 % in patients without organ failure to 91.3 % in patients with failure of al l the six organs analysed. A maximum score was reached 1.1 +/- 0.2 days aft er ad-mission for all the organ systems analysed. The total maximum SOFA sc ore presented an area under the ROC curve of 0.847 (SE 0.012), which was si gnificantly higher than any of its individual components. The cardiovascula r score (odds ratio 1.68) was associated with the highest relative contribu tion to outcome. No independent contribution could be demonstrated for the hepatic score. No significant interactions were found. Principal components analysis demonstrated the existence of a two-factor st ructure that became clearer when analysis was limited to the presence or ab sence of organ failure (SOFA score greater than or equal to 3 points) durin g the ICU stay. The first factor comprises respiratory, cardiovascular and neurological systems and the second coagulation, hepatic and renal systems. Delta SOFA also presented a good correlation to outcome. The area under the receiver operating characteristic (ROC) curve was 0.742 (SE 0.017) for del ta SOFA, lower than the total maximum SOFA score or admission total SOFA sc ore. The impact of delta SOFA on prognosis remained significant after corre ction for admission total SOFA. Conclusions: The results show that total maximum SOFA score and delta SOFA can be used to quantify the degree of dysfunction/failure already present o n ICU admission, the degree of dysfunction/failure that appears during the ICU stay and the cumulative insult suffered by the patient. These propertie s make it a good instrument to be used in the evaluation of organ dysfuncti on/failure.