SOFA is superior to MOD score for the determination of non-neurologic organ dysfunction in patients with severe traumatic brain injury: a cohort study

INTRODUCTION: The objective of the present study was to compare the discriminative ability of the Sequential Organ Failure Assessment (SOFA) and Multiple Organ Dysfunction (MOD) scoring systems with respect to hospital mortality and unfavorable neurologic outcome in patients with severe traumatic brain injury admitted to the intensive care unit. METHOD: We performed a prospective cohort study at Foothills Medical Centre, the sole adult tertiary care trauma center servicing southern Alberta (population about 1.3 million). All patients aged 16 years or older with severe traumatic brain injury and intensive care unit length of stay greater than 48 hours between 1 May 2000 and 31 April 2003 were included. Non-neurologic organ dysfunction was measured using the SOFA and MODS scoring systems. Determination of organ dysfunction for each non-neurologic organ system was compared between the two systems by calculating the proportion of patients with SOFA and MOD component score defined organ failure. Consistent with previous literature, organ system failure was defined as a component score of three or greater. RESULTS: The odds of death and unfavorable neurologic outcome in patients with SOFA defined cardiovascular failure were 14.7 times (95% confidence interval [CI] 5.9–36.3) and 7.6 times (95% CI 3.5–16.3) that of those without cardiovascular failure, respectively. The development of SOFA-defined cardiovascular failure was a reasonable discriminator of hospital mortality and unfavorable neurologic outcome (area under the receiver operating characteristic [ROC] curve 0.75 and 0.73, respectively). The odds of death and unfavorable neurologic outcome in patients with MOD-defined cardiovascular failure were 2.6 times (95% CI 1.24–5.26) and 4.1 times (95% CI 1.3–12.4) that of those without cardiovascular failure, respectively. The development of MOD-defined cardiovascular failure was a poor discriminator of hospital mortality and unfavorable neurologic outcome (area under the ROC curve 0.57 and 0.59, respectively). Neither SOFA-defined nor MOD-defined respiratory failure was significantly associated with hospital mortality. CONCLUSION: In patients with brain injury, the SOFA scoring system has superior discriminative ability and stronger association with outcome compared with the MOD scoring system with respect to hospital mortality and unfavorable neurologic outcome.