title: Unrecognized glucose intolerance is common in pulmonary arterial hypertension.
abstract: BACKGROUND
  Animal and human data suggest insulin resistance is common in pulmonary arterial hypertension (PAH). Although routine assessment of insulin resistance is difficult, hemoglobin A(1c) (HbA(1c)) is a sensitive test to detect diabetes mellitus (DM) and those at high risk for DM. We aimed to define the prevalence of elevated HbA(1c) in PAH patients and to correlate HbA(1c) levels with functional assessment.
  
  
  METHODS
  HbA(1c) was measured in 41 PAH patients without a diagnosis of DM, along with demographic, functional, and hemodynamic data. Using published criteria, HbA(1c) ≤ 5.9% defined normal, 6.0% to 6.4% was glucose intolerance, and ≥ 6.5% was DM.
  
  
  RESULTS
  Twenty-three patients (56%) had HbA(1c) ≥ 6.0%, and 6 (15%) had unrecognized DM (HbA(1c) ≥ 6.5%). Age and body mass index were similar in patients with HbA(1c) ≥ 6.0% vs < 6.0%. There was a trend towards lower mean 6-minute walk distance in patients with elevated HbA(1c) (331.0 ± 126.6 vs 413.6 ± 74.9 meters, p = 0.07). The 6-month event-free survival was not significantly different in patients with elevated HbA(1c).
  
  
  CONCLUSIONS
  Unrecognized glucose intolerance as assessed by HbA(1c) is common in PAH. Further studies are needed to discern if glucose or insulin dysregulation mediates PAH pathogenesis or is secondary to advanced PAH.
authors.affiliation: Division of Allergy, Pulmonary, and Critical Care Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2650, USA. meredith.e.pugh@vanderbilt.edu
authors.forename: Meredith E
authors.initials: ME
authors.lastname: Pugh
authors.forename: Ivan M
authors.initials: IM
authors.lastname: Robbins
authors.forename: Todd W
authors.initials: TW
authors.lastname: Rice
authors.forename: James
authors.initials: J
authors.lastname: West
authors.forename: John H
authors.initials: JH
authors.lastname: Newman
authors.forename: Anna R
authors.initials: AR
authors.lastname: Hemnes
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D015897:Comorbidity; D005260:Female; D018149:Glucose Intolerance / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology*; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis* / Q000453:epidemiology* / Q000503:physiopathology; D007333:Insulin Resistance / Q000502:physiology; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies
chemical_list: D006442:Glycated Hemoglobin