Hospitalizations With Secondary Asthma Rising
Asthma is more often a secondary reason for hospitalization than a principal cause in the United States, and the rate of secondary diagnoses is increasing, according to a report.
From 1997 to 2005, adult hospital stays specifically for asthma remained stable, but the number of secondary asthma diagnoses more than doubled, according to “Hospital Stays Related to Asthma for Adults, 2005,” a statistical brief released by the Agency for Healthcare Research and Quality (AHRQ).
Between 2000 and 2005, hospitalizations for asthma increased 18%, from 247,200 to 290,600. However, the number of hospital stays where asthma was secondary rose from 753,800 to 1,609,200, an increase of 113%.
Pneumonia led the list of primary diagnoses for hospital stays with a secondary asthma coding in 2005, accounting for 123,100 or nearly 7.6% of these stays, Chaya T. Merril and colleagues at the AHRQ's Healthcare Cost and Utilization Project (HCUP) reported.
Heart failure and nonspecific chest pain were the next most common principal diagnoses, collectively accounting for 121,100 hospital stays or 7.5% with a secondary asthma diagnosis. Osteoarthritis (specifically, degenerative joint disease) and mood disorders (depression and bipolar disorder) were each noted in 53,000 (3.3%) of the hospital stays.
Patients aged 65 years and older had more than three times the rate of asthma-related hospitalizations, compared with younger patients. The hospitalization rate per 1,000 population for a primary asthma diagnosis was 0.7 for patients aged 18–44 years, 1.6 for patients aged 45–64, and 2.5 for those aged 65 and older.
Rates also were higher among women—about 2.5 times greater than stays for men. Women had a 1.8 per 1,000 population primary asthma hospitalization rate, compared with 0.7 among men.
Of the 1.9 million asthma-related adult hospital stays in 2005, asthma was a principal diagnosis for 15% and a secondary diagnosis for the other 85%. Mean length of stay was 4.1 days for the primary asthma group and 4.9 days for the secondary group.
Data came from the 2005 Nationwide Inpatient Sample, similar nationally representative samples from 1997 to 2004, and supplemental sources. The database includes all patients regardless of insurance type or uninsured status who were admitted to short-term, nonfederal hospitals. Obstetric and gynecologic facilities; ear, nose, and throat hospitals; and orthopedic, cancer, public, and academic medical hospitals are included.
Of the primary asthma inpatient stays, 74% were admissions through an emergency department, compared with 51% of the secondary diagnosis stays. Of the more than 30 million hospital stays in 2005 with no mention of asthma, 48% were emergency department admissions.
Asthma hospitalization rates were higher in poorer areas of the United States, compared with richer regions. Adults living in a zip code with a median annual income below $36,000 had a 63% higher rate of asthma-related hospital stays, compared with those residing in a zip code with a higher median income. Medicare and Medicaid were billed for about 60% of asthma-related stays, according to the report.
After accounting for differences in length of stay, hospitalizations principally for asthma cost an average $1,400 per day, or about $400 less than the estimated $1,800 per day for hospital stays with secondary asthma. Aggregate costs were about $1.6 billion for primary asthma admissions in 2005, compared with $14.4 billion for secondary asthma stays.
Researchers found little variation in hospitalizations by region. After adjusting for regional population differences, they found approximately two principal asthma stays per 1,000 population in the Northeast, Midwest, and South. The rate was lower in the West at 1.4 stays per 1,000 population.
The AHRQ is scheduled to release a second report on pediatric asthma-related hospital stays in August 2008.
The full report is available at www.hcup-us.ahrq.gov/reports/statbriefs/sb54.pdf
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