Consecutive Measures of CRP Correlate with Length of Hospital Stay in Patients with Community-Acquired Pneumonia.

Background: Accurate diagnosis of community acquired pneumonia (CAP) is crucial to its proper management and to combating antibiotic resistance. Levels of C-reactive protein (CRP) have been shown to distinguish pneumonia from other pathological conditions and can be used to control the severity of infection during admission.
Objectives: To investigate an association between consecutive measurements of CRP and the severity of CAP in hospitalized patients.
Methods: A total of 500 patients with CAP were admitted to the hospital. Traditional markers of inflammation including CRP, leukocyte count, body temperature, were measured on the first, second, and fifth days of hospitalization. Correlations between these measures and the length of the hospital stay were calculated.
Results: Mean levels of CRP, body temperature, and leukocyte count were significantly lower on the second day after hospital admission and even lower on the fifth day. A positive correlation of medium strength was found between the level of CRP on the second day of hospitalization and the length of hospital stay (P < 0.001, rs = 0.447), and a negative correlation was noted between the decrease in CRP level from the first to second day and the length of hospital stay.
Conclusions: CRP levels correlated with body temperature and leukocyte count, traditional markers of inflammation. A greater decrease in CRP level between the first and second day of hospitalization was associated with shorter hospital stay and rapid improvement. These findings support the use of CRP as a marker for the severity and complication of CAP.