Lactate improves SAPS 3 prognostication

Lactate concentration is known to be a strong predictor of mortality, but is not included in any of the major intensive care scorings systems such as the Simplified Acute Physiology Score (SAPS 3). The objective of this study was to investigate the prognostic value of lactate concentration when combined with SAPS 3.

In the period of 2008 to June 2017 the general intensive care unit at Skåne University Hospital in Lund, Sweden had 5141 first-time admissions. Of these, 3039 patients had lactate concentrations analysed within 1 h of admission.

As expected, lactate concentration was found to be strongly related to 30-day mortality. Lactate concentration was found to be a SAPS 3 independent predictor of mortality (odds ratio 1.08, 95% confidence interval 1.05-1.11, P < 0.001), but did not improve the area under the receiver operating characteristic curve (AUC) (AUC 78.9% vs. 78.7%, P = 0.053). However, we found that lactate added prognostic value to SAPS 3 for patients with cardiac arrest (AUC 79.6% vs. 76.4%, P = 0.0082) and sepsis (AUC 75.1% vs. 72.7%, P = 0.033).

Even compared to our current prognostication model, SAPS 3, lactate concentration was found to be an independent predictor for all diagnoses, cardiac arrest and sepsis. The addition of lactate concentration level improved the AUC for cardiac arrest and sepsis, but not for all diagnoses.