Lung injury prediction scores: Clinical validation and C-reactive protein involvement in high risk patients

A study was made to validate two previously derived lung injury prediction scores (LIPS) for the prediction of acute respiratory distress syndrome (ARDS) in high risk intensive care patients, with the incorporation of C-reactive protein (CRP) for improving score accuracy.

A prospective, observational cohort study was carried out.

A total of 200 patients with APACHE II score ≥15 and at least one ARDS risk factor upon ICU admission were included.

Calculation of LIPS using formulas developed by Cartin-Ceba et al. (2009) and Trillo-Alvarez et al. (2011) (LIPS-2009 and LIPS-2011). C-reactive protein was measured upon admission (CRP-0) and after 48h (CRP-48).

Independent variables: LIPS-2009, LIPS-2011 and CRP values. Dependent variable: development of ARDS.

Eighty-eight patients (44%) developed ARDS after a median (Q₁-Q₃) of 2.5 (1.3-6.8) days. The LIPS-2009 and LIPS-2011 scores were 4 (3-6) and 5 (3.6-6.5) in ARDS patients compared to 2 (1-4) and 3.5 (1.5-4.5) in non-ARDS patients (p<0.001). CRP-48 was 96 (67.5-150.3)mg/L and 48 (24-96)mg/L in the two groups, respectively (p<0.001). ΔCRP (i.e., CRP-48 minus CRP-0) was significantly higher in the ARDS patients (p<0.001). The AUC was 0.740 and 0.738 for LIPS-2011 and LIPS-2009, respectively - the difference being nonsignificant (p=0.9, 0.9 and 0.8 for pairwise comparison of the different ROC curves). Integrating ΔCRP with LIPS-2011 using binary logistic regression analysis identified a new score (LIPS-N) with AUC 0.803, which was significantly higher than the AUC of LIPS-2011 (p=0.01).

Both LIPS scores are equally effective in predicting ARDS in high risk ICU patients. Integrating the change in CRP within the score might improve its accuracy.