Objective: To study the recent trends in asthma hospitalization and mortality rates by age, gender, and race categories in the United States.
Methods: The National Hospital Discharge Survey Database for the years 1995 to 2002 was used to examine trends in asthma hospitalization. An International Classification of Diseases Ninth Revision, Clinical Modification (ICD-9-CM) code of 493.0 was used to identify primary hospitalization for asthma. Hospitalization rates were estimated using U.S. Census Bureau population estimates as denominators. Mortality data was obtained from the Center for Disease Control and Prevention Mortality Database. Death from asthma was identified using ICD-9-CM codes (493.0) for the years between 1995 and 1998 and ICD-10 codes (J45-J45.9) for 1999 and afterwards. Asthma hospitalization and mortality rates were estimated per 10,000 and per 100,000 populations, respectively. Crude relative risks (RR) were estimated to compare risks between various groups.
Results: During the study period the age-adjusted asthma hospitalization rate decreased by 16.3% among white females (from 13.4/10,000 in 1995-1996 to 11.2/10,000 in 2001-2002), and by 7% (from 8.14/10,000 in 1995-1996 to 7.56/10,000 in 2001-2002) among white males. Among blacks the decrease in hospitalization rate was by 13.9% (from 38.18/10,000 in 1995-1996 to 32.86/10,000 in 2001-2002) in males and by 14.4% (from 40.21/10,000 in 1995-1996 to 34.42/10,000 in 2001-2002) in females. A narrowing of the black to white disparity in asthma hospitalization rate was noted for children younger than 10 years of age. On the other hand, the racial disparity among subjects 10 years and older narrowed until 2000 but has started to widen since then. The overall decrease in asthma mortality rate was evident for the age group=5, but remained unchanged for the age group less than five. The age adjusted asthma mortality rate has also decreased by 22.2% in blacks (from 3.33/100,000 in 1995 to 2.59/100,000 in 2001) and by 38.4% in whites (from 1.26/100,000 in 1995 to 0.78/100,000 in 2001).
Conclusion: This study confirms that both asthma hospitalization and mortality rates decreased during the study period and the black to white racial disparity in asthma hospitalization has narrowed for children younger than 10 years of age. For those subjects 10 years and older the racial disparity in hospitalizations narrowed until 2000 but started to widen since then. The widening racial gap in adults is disconcerting and needs further observation to assess its persistence.