C-reactive protein for discriminating treatment failure from slow responding pneumonia.
BACKGROUND
The management of patients with community-acquired pneumonia (CAP) who fail to improve constitutes a challenge for clinicians. This study investigated the usefulness of C-reactive protein (CRP) changes in discriminating true treatment failure from slow response to treatment.


METHODS
This prospective multicenter observational study investigated the behavior of plasma CRP levels on days 1 and 4 in hospitalized patients with CAP. We identified non-responding patients as those who had not reached clinical stability by day 4. Among them, true treatment failure and slow response situations were defined when initial therapy had to be changed or not after day 4 by attending clinicians, respectively.


RESULTS
By day 4, 78 (27.4%) out of 285 patients had not reached clinical stability. Among them, 56 (71.8%) patients were cured without changes in initial therapy (mortality 0.0%), and in 22 (28.2%) patients, the initial empirical therapy needed to be changed (mortality 40.9%). By day 4, CRP levels fell in 52 (92.9%) slow responding and only in 7 (31.8%) late treatment failure patients (p<0.001). A model developed including CRP behavior and respiratory rate at day 4 identified treatment failure patients with an area under the Receiver Operating Characteristic curve of 0.87 (CI 95%, 0.78-0.96).


CONCLUSIONS
Changes in CRP levels are useful to discriminate between true treatment failure and slow response to treatment and can help clinicians in management decisions when CAP patients fail to improve.
Hospital Universitari Arnau de Vilanova, Institut de Recerca Biomèdica de Lleida, Lleida, Spain. agustinruiz@saludalia.com
Agustín
A
Ruiz-González
Miquel
M
Falguera
José Manuel
JM
Porcel
Montserrat
M
Martínez-Alonso
Pamela
P
Cabezas
Paloma
P
Geijo
Ramón
R
Boixeda
Carlos
C
Dueñas
Arola
A
Armengou
Josep Antoni
JA
Capdevila
Regino
R
Serrano
D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism*; D023521:Chlamydophila Infections / Q000188:drug therapy / Q000401:mortality; D016993:Chlamydophila pneumoniae / Q000187:drug effects; D017714:Community-Acquired Infections / Q000188:drug therapy* / Q000401:mortality; D016997:Coxiella burnetii / Q000187:drug effects; D016903:Drug Monitoring / Q000379:methods*; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D016952:Legionella pneumophila / Q000187:drug effects; D007877:Legionnaires' Disease / Q000188:drug therapy / Q000401:mortality; D008297:Male; D008875:Middle Aged; D009177:Mycoplasma pneumoniae / Q000187:drug effects; D011008:Pneumococcal Infections / Q000188:drug therapy / Q000401:mortality; D018410:Pneumonia, Bacterial / Q000188:drug therapy* / Q000401:mortality; D011019:Pneumonia, Mycoplasma / Q000188:drug therapy / Q000401:mortality; D011778:Q Fever / Q000188:drug therapy / Q000401:mortality; D013296:Streptococcus pneumoniae / Q000187:drug effects; D017211:Treatment Failure
D000900:Anti-Bacterial Agents; D015415:Biomarkers; D002097:C-Reactive Protein