Asthma Surveillance: Characterizing Patients who had Multiple Asthma Emergency Department Visits or Hospitalizations in 2011 and During the 5-Year Period, 2007-2011

BACKGROUND: Visits to emergency rooms and hospitalizations are often indicators of asthma severity or poor asthma control. There is increasing interest in identifying and characterizing patients with repeated asthma healthcare events. The purpose of this analysis of hospital discharge and emergency department (ED) visit data was: (1) to determine the prevalence of patients with single versus multiple visits for primary-diagnosed asthma during 2011 and over the 5-year period 2007-2011; and (2) to characterize the demographics among these patients.

METHODS: We conducted a retrospective analysis of asthma patients using Wisconsin hospital inpatient discharge and ED visit data between 2007 and 2011. Confidential data elements within each data set were used to create a longitudinal patient identifier for linking across hospitals. This ID based on initials, date of birth, sex and zip code of resident was used to identify individual patients with repeat asthma hospitalizations (within the 12 months of calendar year 2011 and five-year period, 2007-2011) and repeat asthma ED visits during 2011. The prevalence and distribution of patients with single versus multiple events were compared by sex, age at initial visit and race.

RESULTS: The 4,704 asthma hospitalizations in 2011 represented 4,063 individual patients, of which 438 (10.8%) had at least one additional hospitalization during that year (8.0% had 2 visits, 2.6% had 3-5 visits and <1% had more than 5 visits). Over five years (2007-2011), the number of patients with repeat visits approached 20%. Of the 15,671 individual patients with asthma ED visits in 2011 (19,280 total visits), 86.2% had a single visit and 13.8% had two or more visits that year. A greater proportion of repeat to single hospitalizations occurred among females, the middle-aged (35-64 years) and non-White race, specifically African Americans and American Indians. With respect to seasonality, patients with repeat events had a greater proportion of ED visits and hospitalizations during summer months.

CONCLUSIONS: By examining repeat hospitalizations and ED visits, asthma management rather than the incidence or diagnosis of the disease can be assessed. Because asthma is widely considered a preventable cause of hospitalization, a readmission may be an indication of failed asthma management. The cost of the initial asthma hospitalization for Wisconsin patients with repeat visits in 2011 was $5.9 million, and the additional visits added $9.1 million. The excess costs show that improvements in asthma management could result in substantial savings, in addition to enhanced quality of life for these patients.