title: Effect of pregnancy in asthma on health care use and perinatal outcomes.
abstract: BACKGROUND
  It is generally known that pregnancy in asthmatic patients increases the risk of asthma exacerbations and poor perinatal outcomes. However, the effect of pregnancy in asthmatic patients on health care use is not known well. In addition, its effect on perinatal outcomes is still controversial because of study limitations caused by ethical issues. National Health Insurance claim data are an ideal resource for studying real-world health care use patterns of asthma.
  
  
  OBJECTIVE
  We sought to evaluate the effect of pregnancy on asthma in terms of asthma-related health care use and prescription patterns in concert with the effect of asthma exacerbations on adverse pregnancy outcomes.
  
  
  METHODS
  Among all asthmatic patients in the Korean National Health Insurance claim database from January 2009 to December 2013, pregnant women who delivered in 2011 with pre-existing asthma were enrolled. Analyses included asthma-related health care use and prescription patterns compared between pregnant asthmatic women and nonpregnant female asthmatic control subjects, as well as within the pregnant subjects from before pregnancy throughout postpartum periods. In addition, the association between asthma exacerbation during pregnancy and adverse pregnancy outcomes was assessed.
  
  
  RESULTS
  A total of 3,357 pregnant asthmatic patients were compared with 50,355 nonpregnant asthmatic patients, and 10,311 pregnant patients were included to determine the effect of asthma exacerbations on adverse pregnancy outcome in the study. Pregnant asthmatic patients underwent more asthma-related hospitalizations (1.3% vs 0.8%, P = .005) but had significantly fewer outpatient visits and prescriptions for most asthma medications than nonpregnant asthmatic patients. The proportion of patients ever hospitalized gradually increased throughout pregnancy (first trimester, 0.2%; second trimester, 0.5%; and third trimester, 0.7%; P = .018). The prevalence of asthma exacerbation during pregnancy was 5.3%, and the patients who had acute exacerbation during pregnancy had significantly higher asthma-related health care use in terms of hospitalization, intensive care unit admission, and emergency department and outpatient visits within 1 year before delivery than those who had not. However, asthma exacerbation during pregnancy was not significantly related to adverse perinatal outcomes, except for cesarean section (27.1% vs 18.9%, P < .001). All exacerbations were managed with systemic corticosteroids, and the patients who ever experienced acute exacerbations maintained asthma medications, including inhaled corticosteroid-based inhalers, throughout the pregnancy period.
  
  
  CONCLUSIONS
  Pregnancy profoundly affects asthma-related health care use but to a different degree depending on whether the patient experienced an exacerbation. Asthma exacerbation during pregnancy is not associated with adverse pregnancy outcomes while managed appropriately with systemic corticosteroids. However, further studies are needed to clarify the effect of asthma control on perinatal outcome and delivery method.
authors.affiliation: Department of Allergy and Clinical Immunology, Asthma Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea; Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu, Korea.
authors.forename: Sujeong
authors.initials: S
authors.lastname: Kim
authors.affiliation: National Evidence-based Healthcare Collaborating Agency, Seoul, Korea; Department of Nursing, College of Medicine, Chosun University, Gwangju, Korea.
authors.forename: Jinhee
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Allergy and Clinical Immunology, Asthma Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: So Young
authors.initials: SY
authors.lastname: Park
authors.affiliation: Korea Institute of Drug Safety and Risk Management, Seoul, Korea.
authors.forename: Hye-Yeon
authors.initials: HY
authors.lastname: Um
authors.affiliation: National Evidence-based Healthcare Collaborating Agency, Seoul, Korea.
authors.forename: Kyoungjoo
authors.initials: K
authors.lastname: Kim
authors.affiliation: National Evidence-based Healthcare Collaborating Agency, Seoul, Korea.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Kim
authors.affiliation: Department of Statistics, Dongguk University, Seoul, Korea.
authors.forename: Yunjin
authors.initials: Y
authors.lastname: Park
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, Asan Medical Center, Seoul, Korea.
authors.forename: Seunghee
authors.initials: S
authors.lastname: Baek
authors.affiliation: Department of Allergy and Clinical Immunology, Asthma Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Sun-Young
authors.initials: SY
authors.lastname: Yoon
authors.affiliation: Department of Allergy and Clinical Immunology, Asthma Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Hyouk-Soo
authors.initials: HS
authors.lastname: Kwon
authors.affiliation: Department of Allergy and Clinical Immunology, Asthma Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: You Sook
authors.initials: YS
authors.lastname: Cho
authors.affiliation: Department of Allergy and Clinical Immunology, Asthma Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Hee-Bom
authors.initials: HB
authors.lastname: Moon
authors.affiliation: Department of Allergy and Clinical Immunology, Asthma Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea. Electronic address: tbkim@amc.seoul.kr.
authors.forename: Tae-Bum
authors.initials: TB
authors.lastname: Kim
mesh_terms: D000328:Adult; D001249:Asthma / Q000453:epidemiology*; D002585:Cesarean Section / Q000706:statistics & numerical data*; D018450:Disease Progression; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007345:Insurance Claim Review; D008875:Middle Aged; D009313:National Health Programs; D010342:Patient Acceptance of Health Care / Q000706:statistics & numerical data*; D010818:Practice Patterns, Physicians'; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology*; D011256:Pregnancy Outcome; D015995:Prevalence; D056910:Republic of Korea / Q000453:epidemiology; D055815:Young Adult
keywords: Asthma; health care; insurance claim review; pregnancy