Serum immunoglobulin G (IgG) levels can help signal which COPD patients are at higher risk for hospitalization, a Chest study found. Researchers analyzed pooled data from 4 large clinical studies of COPD: Azithromycin for Prevention of Exacerbation of COPD (MACRO; ClinicalTrials.gov Identifier: NCT00325897); Simvastatin for the Prevention of Exacerbations in Moderate-to-Severe COPD (STATCOPE; ClinicalTrials.gov Identifier: NCT01061671); Long-Term Oxygen Treatment Trial (LOTT; ClinicalTrials.gov Identifier: NCT00692198); and COPD Activity: Serotonin Transporter, Cytokines and Depression (CASCADE; ClinicalTrials.gov Identifier: NCT01074515). The investigators sought to establish the relationship between hypogammaglobulinemia and risk for hospitalization in patients with COPD. They measured serum IgG levels on baseline samples from the different COPD cohorts. A total of 2259 participants were considered for IgG analysis (MACRO n=976; STACOPE n=653; LOTT n=354; and CASCADE n=276). IgG concentrations were determined by immunonephelometry in the MACRO and STATCOPE cohorts or by mass spectrometry in the LOTT and CASCADE cohorts. Get the full story at Pulmonaryadvisor.com.