Utility of the combination of serum highly-sensitive C-reactive protein level at discharge and a risk index in predicting readmission for acute exacerbation of COPD

Abstract

Objective: Frequent readmissions for acute exacerbations of COPD (AECOPD) are an independent risk factor for increased mortality and use of health-care resources. Disease severity and C-reactive protein (CRP) level are validated predictors of long-term prognosis in such patients. This study investigated the utility of combining serum CRP level with the Global Initiative for Chronic Obstructive Lung Disease (GOLD) exacerbation risk classification for predicting readmission for AECOPD.

Methods: This was a prospective observational study of consecutive patients hospitalized for AECOPD at Peking University Third Hospital, in Beijing, China. We assessed patient age; gender; smoking status and history (pack-years); lung function; AECOPD frequency during the last year; quality of life; GOLD risk category (A-D; D indicating the greatest risk); and serum level of high-sensitivity CRP at discharge (hsCRP-D).

Results: The final sample comprised 135 patients. Of those, 71 (52.6%) were readmitted at least once during the 12-month follow-up period. The median (interquartile) time to readmission was 78 days (42-178 days). Multivariate analysis revealed that serum hsCRP-D ≥ 3 mg/L and GOLD category D were independent predictors of readmission (hazard ratio = 3.486; 95% CI: 1.968-6.175; p < 0.001 and hazard ratio = 2.201; 95% CI: 1.342-3.610; p = 0.002, respectively). The ordering of the factor combinations by cumulative readmission risk, from highest to lowest, was as follows: hsCRP-D ≥ 3 mg/L and GOLD category D; hsCRP-D ≥ 3 mg/L and GOLD categories A-C; hsCRP-D < 3 mg/L and GOLD category D; hsCRP-D < 3 mg/L and GOLD categories A-C.

Conclusions: Serum hsCRP-D and GOLD classification are independent predictors of readmission for AECOPD, and their predictive value increases when they are used in combination.

Figure 1. Kaplan-Meier curves showing readmission for acute exacerbation of COPD (AECOPD) during the 12-month follow-up period after the index AECOPD. The curves for readmission are presented for the four subgroups of the patient cohort, categorized on the basis of the patient serum level of high-sensitivity C-reactive protein (hsCRP) at discharge and the Global Initiative for Chronic Obstructive Lung Disease (GOLD) risk category. The order of the groups, ranked from highest to lowest readmission rate (p < 0.001), was as follows: serum hsCRP = 3 mg/L and GOLD category D; serum hsCRP = 3 mg/L and GOLD categories A-C; serum hsCRP < 3 mg/L and GOLD category D; and serum hsCRP < 3 mg/L and GOLD categories A-C.

Figura 1. Curvas de Kaplan-Meier mostrando a reinternação por exacerbação aguda da DPOC (EADPOC) durante o período de 12 meses de acompanhamento após a primeira EADPOC. As curvas de reinternação são apresentadas para os quatro subgrupos da coorte de pacientes, categorizados em função do nível sérico de proteína C reativa de alta sensibilidade (PCRas) no momento da alta e da categoria de risco da Global Initiative for Chronic Obstructive Lung Disease (GOLD). A ordem dos grupos, da maior para a menor taxa de reinternação (p < 0,001), foi a seguinte: PCRas sérica = 3 mg/L e categoria GOLD D; PCRas sérica = 3 mg/L e categoria GOLD A-C; PCRas sérica < 3 mg/L e categoria GOLD D; PCRas sérica < 3 mg/L e categoria GOLD A-C.