Evaluation of trends in organ dysfunction in critically ill patients
may help predict outcome.
To determine the usefulness of repeated measurement the Sequential Organ
Failure Assessment (SOFA) score for prediction of mortality in intensive care
unit (ICU) patients.
Prospective, observational cohort study conducted from April 1 to July
A 31-bed medicosurgical ICU at a university hospital in Belgium.
Three hundred fifty-two consecutive patients (mean age, 59 years) admitted
to the ICU for more than 24 hours for whom the SOFA score was calculated on
admission and every 48 hours until discharge.
Main Outcome Measures
Initial SOFA score (0-24), Δ-SOFA scores (differences between
subsequent scores), and the highest and mean SOFA scores obtained during the
ICU stay and their correlations with mortality.
The initial, highest, and mean SOFA scores correlated well with mortality.
Initial and highest scores of more than 11 or mean scores of more than 5 corresponded
to mortality of more than 80%. The predictive value of the mean score was
independent of the length of ICU stay. In univariate analysis, mean and highest
SOFA scores had the strongest correlation with mortality, followed by Δ-SOFA
and initial SOFA scores. The area under the receiver operating characteristic
curve was largest for highest scores (0.90; SE, 0.02; P<.001 vs initial score). When analyzing trends in the SOFA score
during the first 96 hours, regardless of the initial score, the mortality
rate was at least 50% when the score increased, 27% to 35% when it remained
unchanged, and less than 27% when it decreased. Differences in mortality were
better predicted in the first 48 hours than in the subsequent 48 hours. There
was no significant difference in the length of stay among these groups. Except
for initial scores of more than 11 (mortality rate >90%), a decreasing score
during the first 48 hours was associated with a mortality rate of less than
6%, while an unchanged or increasing score was associated with a mortality
rate of 37% when the initial score was 2 to 7 and 60% when the initial score
was 8 to 11.
Sequential assessment of organ dysfunction during the first few days
of ICU admission is a good indicator of prognosis. Both the mean and highest
SOFA scores are particularly useful predictors of outcome. Independent of
the initial score, an increase in SOFA score during the first 48 hours in
the ICU predicts a mortality rate of at least 50%.