title: Age-Related Differences in the Rate, Timing, and Diagnosis of 30-Day Readmissions in Hospitalized Adults With Asthma Exacerbation.
abstract: BACKGROUND
  Reducing hospital readmissions has attracted attention from many stakeholders. However, the characteristics of 30-day readmissions after asthma-related hospital admissions in adults are not known. It is also unclear whether older adults are at higher risk of 30-day readmission.
  
  
  OBJECTIVE
  To investigate the rate, timing, and principal diagnosis of 30-day readmissions in adults with asthma and to determine age-related differences.
  
  
  METHODS
  Retrospective cohort study of adults hospitalized for asthma exacerbation using the population-based inpatient samples of three states (California, Florida, and Nebraska) from 2005 through 2011. Patients were categorized into three age groups: younger (18-39 years), middle aged (40-64 years), and older (≥ 65 years) adults. Outcomes were 30-day all-cause readmission rate, timing, and principal diagnosis of readmission.
  
  
  RESULTS
  Of 301,164 asthma-related admissions at risk for 30-day readmission, readmission rate was 14.5%. Compared with younger adults, older adults had significantly higher readmission rates (10.1% vs 16.5%; OR, 2.15 [95% CI, 2.07-2.23]; P < .001). The higher rate attenuated with adjustment (OR, 1.19 [95% CI, 1.13-1.26]; P < .001), indicating that most of the age-related difference is explained by sociodemographics and comorbidities. For all age groups, readmission rate was highest in the first week after discharge and declined thereafter. Overall, only 47.1% of readmissions were assigned respiratory diagnoses (asthma, COPD, pneumonia, and respiratory failure). Older adults were more likely to present with nonrespiratory diagnoses (41.7% vs 53.8%; P < .001).
  
  
  CONCLUSIONS
  After asthma-related admission, 14.5% of patients had 30-day readmission with wide range of principal diagnoses. Compared with younger adults, older adults had higher 30-day readmission rates and proportions of nonrespiratory diagnoses.
authors.affiliation: Department of Emergency Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA. Electronic address: khasegawa1@partners.org.
authors.forename: Kohei
authors.initials: K
authors.lastname: Hasegawa
authors.affiliation: Biostatistics Center, Kurume University, Kurume, Fukuoka, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Gibo
authors.affiliation: Department of Health Policy and Management, Harvard T.H. Chan School of Public Health, Boston, MA.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Tsugawa
authors.affiliation: Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA.
authors.forename: Yuichi J
authors.initials: YJ
authors.lastname: Shimada
authors.affiliation: Department of Emergency Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA; Division of Rheumatology, Allergy, and Immunology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Camargo
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001249:Asthma / Q000453:epidemiology*; D002140:California / Q000453:epidemiology; D015331:Cohort Studies; D015897:Comorbidity; D016208:Databases, Factual; D003863:Depression / Q000453:epidemiology; D003920:Diabetes Mellitus / Q000453:epidemiology; D018450:Disease Progression; D005006:Ethnicity / Q000706:statistics & numerical data*; D005260:Female; D005431:Florida / Q000453:epidemiology; D006333:Heart Failure / Q000453:epidemiology; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007182:Income / Q000706:statistics & numerical data*; D007348:Insurance, Health / Q000706:statistics & numerical data*; D007902:Length of Stay / Q000706:statistics & numerical data; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009329:Nebraska / Q000453:epidemiology; D009765:Obesity / Q000453:epidemiology; D010359:Patient Readmission / Q000706:statistics & numerical data*; D011014:Pneumonia / Q000453:epidemiology*; D016016:Proportional Hazards Models; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology; D051437:Renal Insufficiency / Q000453:epidemiology; D012131:Respiratory Insufficiency / Q000453:epidemiology*; D012189:Retrospective Studies; D019966:Substance-Related Disorders / Q000453:epidemiology; D013997:Time Factors; D055815:Young Adult
keywords: COPD; adults; asthma exacerbation; readmission
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