Impact of Age and Sex on Outcomes and Hospital Cost of Acute Asthma in the United States, 2011-2012.
BACKGROUND
Worldwide, asthma is a leading cause of morbidity, mortality and economic burden, with significant gender and racial disparities. However, little attention has been given to the independent role of age on lifetime asthma severity and hospitalization. We aimed to assess the effect of age, gender, race and ethnicity on indicators of asthma severity including asthma related hospitalization, mortality, hospital cost, and the rate of respiratory failure.


METHODS
We analyzed the 2011 and 2012 Healthcare Cost and Utilization Project- National Inpatient Sample (NIS). We validated and extended those results using the National Heart, Lung, and Blood Institute-Severe Asthma Research Program (SARP; 2002-2011) database. Severe asthma was prospectively defined using the stringent American Thoracic Society (ATS) definition.


RESULTS
Hospitalization for asthma was reported in 372,685 encounters in 2012 and 368,528 in 2011. The yearly aggregate cost exceeded $2 billion. There were distinct bimodal distributions for hospitalization age, with an initial peak at 5 years and a second at 50 years. Likewise, this bimodal age distribution of patients with severe asthma was identified using SARP. Males comprised the majority of individuals in the first peak, but women in the second. Aggregate hospital cost mirrored the bimodal peak distribution. The probability of respiratory failure increased with age until the age of 60, after which it continued to increase in men, but not in women.


CONCLUSIONS
Severe asthma is primarily a disease of young boys and middle age women. Greater understanding of the biology of lung aging and influence of sex hormones will allow us to plan for targeted interventions during these times in order to reduce the personal and societal burdens of asthma.
Department of Pathobiology, Lerner Research Institute, and Respiratory Institute, Cleveland Clinic, Cleveland, Ohio, United States of America.
Joe G
JG
Zein
Department of Outcomes Research, Anesthesiology Institute, Cleveland Clinic, Cleveland, Ohio, United States of America.
Belinda L
BL
Udeh
Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia, United States of America.
W Gerald
WG
Teague
Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, Ohio, United States of America.
Siran M
SM
Koroukian
Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, Ohio, United States of America.
Nicholas K
NK
Schlitz
Center for Genomics and Personalized Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America.
Eugene R
ER
Bleecker
Department of Medicine, the University of Wisconsin, School of Medicine and Public Health, Madison, Wisconsin, United States of America.
William B
WB
Busse
Department of Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America.
William J
WJ
Calhoun
Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America.
Mario
M
Castro
Department of Pathobiology, Lerner Research Institute, and Respiratory Institute, Cleveland Clinic, Cleveland, Ohio, United States of America.
Suzy A
SA
Comhair
Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, United States of America.
Anne M
AM
Fitzpatrick
Pulmonary Division, Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts, United States of America.
Elliot
E
Israel
The Asthma Institute, the University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
Sally E
SE
Wenzel
The Asthma Institute, the University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
Fernando
F
Holguin
Department of Pediatric, Rainbow Babies & Children's Hospital, Cleveland, Ohio, United States of America.
Benjamin M
BM
Gaston
Department of Pathobiology, Lerner Research Institute, and Respiratory Institute, Cleveland Clinic, Cleveland, Ohio, United States of America.
Serpil C
SC
Erzurum
D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001249:Asthma / Q000191:economics* / Q000453:epidemiology* / Q000401:mortality; D002648:Child; D005260:Female; D017721:Hospital Costs; D006760:Hospitalization / Q000191:economics; D006801:Humans; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D014481:United States / Q000453:epidemiology; D055815:Young Adult