CRP and chronic obstructive pulmonary disease: By using Multivariate logistic regression analysis for readmission in COPD patients with or without CAP, it was found that length of hospital stay and C- reactive protein were significant causes with readmission and this was stated in Jing study that systemic inflammatory marker as C- reactive protein was a good predictor for readmission than sputum inflammatory markers [19] and confirmed in Rinne study stated that longer length of hospital stay for COPD hospitalizations was accompanied with a higher risk for readmission [20].