Prospective multicenter study of relapse following emergency department treatment of COPD exacerbation

Study objectives: To determine the incidence and risk factors of relapse after an emergency department (ED) visit for COPD exacerbation. Design: Prospective cohort study as part of the Multicenter Airway Research Collaboration. Setting: Twenty-nine North American EDs. Patients: ED patients with COPD exacerbations, age greater than or equal to 55 years. For the present analysis of post-ED relapse, the cohort was restricted to COPD patients who had been discharged from the ED directly to home. Measurements and results: Eligible patients underwent a structured interview to assess their demographic characteristics, COPD history, and details of the current COPD exacerbation. Data on ED medical management and disposition were obtained by chart review. Patients were contacted by telephone 2 weeks later regarding incident relapse events (ie, urgent clinic or ED visit for worsening COPD). The cohort consisted of 140 COPD patients. Over the next 2 weeks, patients demonstrated a consistent daily relapse rate that summed to 21% (95% confidence interval, 15 to 28%) at day 14. In a multivariate model, the significant risk factors for relapse were the number of urgent clinic or ED visits for COPD exacerbation in the past year (odds ratio [OR], 1.49 [per five visits]), self-reported activity limitation during the past 24 h (OR, 2.93 [per unit on scale of 1 [none] to 4 [severe]), and respiratory rate at ED presentation (OR, 1.76 [per 5 breaths/min]). Conclusions: Among patients discharged to home after ED treatment of a COPD exacerbation, one in five patients will experience an urgent/emergent relapse event during the next 2 weeks. Both chronic factors (ie, a history of urgent clinic or ED visits) and acute factors (ie, activity limitations and initial respiratory rate) are associated with increased risk. Further research should focus on ways to decrease the relapse rate among these high-risk patients. The clinicians may wish to consider these historical factors when making ED decisions.