Patterns of C-reactive protein ratio response in severe community-acquired pneumonia: a cohort study.
Crit Care. 2012 Mar 26;16(2):R53
Authors: Coelho LM, Salluh JI, Soares M, Bozza F, Verdeal JC, Castro-Faria-Neto HC, Lapa E Silva JR, Bozza PT, Povoa P
ABSTRACT: INTRODUCTION: Community-acquired pneumonia (CAP) requiring intensive care unit (ICU) admission remains a severe medical condition, presenting ICU mortality rates reaching 30%. The aim of this study was to assess the value of different patterns of C-reactive protein (CRP)-ratio response to antibiotic therapy in patients with severe CAP requiring ICU admission as an early maker of outcome. METHODS: A total of 191 patients with severe CAP were prospectively included and CRP was sampled every other day from D1 to D7 of antibiotic prescription. CRP-ratio was calculated in relation to D1 CRP concentration. Patients were classified according to an individual pattern of CRP-ratio response with the following criteria: fast response - when D5 CRP was [less than or equal to]0.4 of D1 CRP concentration; slow response - when D5 CRP was >0.4 and D7 [less than or equal to]0.8 of D1 CRP concentration; nonresponse - when D7 CRP was >0.8 of D1 CRP concentration. Comparison between ICU survivors and non-survivors was performed. RESULTS: CRP-ratio from D1 to D7 decreased faster in survivors than in non-survivors (p=0.01). The ability of CRP-ratio by D5 to predict ICU outcome assessed by the area under the ROC curve was 0.73 (95% Confidence Interval, 0.64 - 0.82). By D5, a CRP concentration above 0.5 of the initial level was a marker of poor outcome (sensitivity 0.81, specificity 0.58, positive likelihood ratio 1.93, negative likelihood ratio 0.33). The time-dependent analysis of CRP-ratio of the three patterns (fast response n=66; slow response n=81; nonresponse n=44) was significantly different between groups (p<0.001). The ICU mortality rate was considerably different according to the patterns of CRP-ratio response: fast response 4.8%, slow response 17.3% and nonresponse 36.4% (p<0.001). CONCLUSIONS: In severe CAP, sequential evaluation of CRP-ratio was useful in the early identification of patients with poor outcome. The evaluation of CRP-ratio pattern of response to antibiotics during the first week of therapy was useful in the recognition of the individual clinical evolution.
PMID: 22449513 [PubMed - as supplied by publisher]