Admission lactate predicts poor prognosis independently of the CRB/CURB-65 scores in community-acquired pneumonia

Objectives:

Community-acquired pneumonia (CAP) is associated with a high risk of respiratory failure or septic organ dysfunction. Lactate is an established early marker of prognosis and sepsis severity, but few data exist in patients with CAP.

Methods:

We performed a retrospective cohort study of consecutive adult CAP patients without treatment restrictions or direct ICU admission. Lactate was measured as point of care test within the capillary admission blood gas analysis and its prognostic value was compared to the CRB/CURB-65 criteria by multivariate and ROC curve analysis. The primary endpoint was the combination of need for mechanical ventilation, vasopressors, ICU admission or hospital mortality.

Results:

Of 303 included patients, 75 (25%) met the primary endpoint. After ROC analysis, lactate predicted the primary endpoint (AUC 0.67) with an optimal cut-off of > 1.8 mmol/l. Of the 76 patients presenting with lactate above this threshold, 35 (46%) met the primary endpoint. After multivariate analysis, the predictive value of lactate was independent of the CRB/CURB-65-scores. The addition of lactate > 1.8 mmol/l to the CRB/CURB-65 scores resulted in significantly improved AUCs (0.69 to 0.74, p = 0.005 and 0.71 to 0.75, p = 0.008, respectively). Fourteen of 33 (42%) and 11 of 28 (39%) patients meeting the endpoint despite presenting with 0 or 1 CRB-65/CURB-65 criteria had lactate > 1.8 mmol/l.

Conclusions:

Admission lactate levels significantly improved the prognostic value of the CRB/CURB-65 scores in CAP patients. Lactate therefore should be considered as rapid, cheap and broadly available additional criterion for the assessment of risk in patients with CAP.