Reply to Soo Hoo and Esquinas: Risk Trajectories of Readmission and Death in the First Year after Hospitalization for Chronic Obstructive Pulmonary Disease: Don’t Shortchange Noninvasive Ventilation

From the Authors:

As has been demonstrated in both randomized trials and through causal inference methods applied to real-world data, the application of noninvasive ventilation can reduce the risk of mortality compared with usual care by approximately 50% among patients hospitalized for severe exacerbation of chronic obstructive pulmonary disease (COPD) (1). In fact, noninvasive ventilation is the only therapy we offer to patients in the inpatient setting that has been shown to have a mortality benefit. It is thus encouraging to note that the use of noninvasive ventilation has increased steadily in recent years, eclipsing invasive ventilation as the initial strategy of choice in the management of acute respiratory failure (2).

Our recent study focused on exploring the dynamic nature of the risk of readmission and death in the year after a hospitalization for COPD (3). Our key finding was that the risk of adverse events remains high for an extended period after hospitalization and that the time required for the risk of readmission to fall by 50% and ultimately plateau is far longer in both absolute and relative terms compared with the risk of death. Moreover, in comparison with elderly Medicare beneficiaries without a history of hospitalization for COPD, the risk of admission and death remains many times higher than that observed in age-matched control subjects even 1 year after discharge. Our analysis highlighted the short- and long-term vulnerability of patients after hospitalization for COPD, particularly among those treated with mechanical ventilation—both invasive and noninvasive—and suggested that care management interventions limited to a brief period after discharge may be insufficient to improve long-term outcomes.

Importantly, our analysis was limited to patients who were discharged alive from the hospital. As Dr. Soo Hoo and Dr. Esquinas note, among patients who survived to discharge, mortality at 1 year was 45.7% in those treated with invasive ventilation as compared with 41.8% in those treated with noninvasive ventilation (an 8.5% relative difference). Conversely, readmission was actually more common among those treated with noninvasive ventilation than among those treated with invasive ventilation. Although these differences were not negligible, the magnitude of the mortality benefit was greatly attenuated compared with estimates derived from studies that included inpatient outcomes. Finally, the figures we created were intended to reveal the daily risk of death and readmission; in this context, the trajectories were nearly indistinguishable, especially with increased time after discharge.