Temporal trends in hospitalization rates for older adults with chronic obstructive pulmonary disease

Abstract

Background: Over the last 15 years, substantial advances have been made in the treatment of chronic obstructive pulmonary disease (COPD). Little information is available, however, on whether these treatments have resulted in reduced rates of hospitalization and acute exacerbations among COPD patients. This retrospective cohort study examined changes in hospitalization rates among Medicare beneficiaries with COPD from 1999 to 2008.

Methods: We analyzed data from 424,418 fee-for-service Medicare beneficiaries enrolled between 1999 and 2008 who were diagnosed with COPD. We examined temporal changes in the frequency of hospitalization and acute exacerbations among Medicare beneficiaries with COPD.

Results: Over the 10-year study period, the hospitalization rates for COPD patients--adjusted for age, sex, race, socioeconomic status, region, and number of comorbidities--decreased: from 131 to 107 per 100 person-years for all causes (P <.001); from 58 to 44 per 100 person-years for all respiratory causes (P <.001); and from 73 to 63 per 100 person-years for nonrespiratory causes (P <.001). There was no change in prevalence of COPD in the Medicare population over this time. Additionally, the percentage of COPD patients hospitalized with 2 or more acute exacerbations decreased from 5.5% to 4.3% over the 10-year study period (P <.001).

Conclusion: Between 1999 and 2008, hospitalization rates decreased substantially among Medicare beneficiaries diagnosed with COPD.

Figure 1

Number of all cause, all respiratory, and all non-respiratory hospitalizations per 100 person-years among patients with COPD, 1999–2008.

1. Patients with chronic obstructive pulmonary disease (COPD) are defined as: 1) 2 outpatient professional claims, with different dates of service, with a COPD diagnosis listed in any position; 2) one acute care hospitalization with a COPD diagnosis based on International Classification of Diseases, 9th Revision (ICD-9) code 491.x [chronic bronchitis], 492.x [emphysema], or 496 [chronic airway obstruction]) listed in primary position as a discharge diagnosis; or 3) one acute care hospitalization with respiratory failure (518.81, 518.82, 518.84) listed in the primary position as a discharge diagnosis and COPD listed as the secondary diagnosis.

2. For all 3 outcomes, linear contrast was tested in generalized estimating equation (GEE) model and yielded P values of < .0001.

Figure 2

Percent of chronic obstructive pulmonary disease (COPD) patients with 1, 2, or 3 or more hospitalizations for severe exacerbations of COPD, over time. Acute exacerbation of COPD is defined as International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) 491.21 in the primary discharge diagnosis position.