title: Ventilatory inefficiency in major depressive disorder: a potential adjunct for cardiac risk stratification in depressive disorders?
abstract: BACKGROUND
  Cardiopulmonary exercise testing (CPET) provides insights into ventilatory, cardiac and metabolic dysfunction in heart and lung diseases and might play a role in cardiac risk stratification in major depressive disorder (MDD).
  
  
  OBJECTIVE
  The VE/VCO(2)-slope indicates ventilatory efficiency and has been applied to stratify the cardiac risk in heart failure (HF). Therefore, the current study was conducted to evaluate and classify ventilatory efficiency and its relationship to physical fitness and disease severity in MDD.
  
  
  METHODS
  Exhaustive incremental exercise testing was completed by 15 female MDD patients and pair matched controls. The ventilatory threshold (VT) and the VE/VCO(2)-slope were assessed. Statistical analyses were conducted by means of MANOVAs and follow-up univariate ANOVAs.
  
  
  RESULTS
  In patients with MDD, significant different relative work rates and oxygen uptakes at the VT in comparison to healthy controls were observed. Furthermore, we found an increased VE/VCO(2)-slope in depressed patients. We additionally report an inverse relationship between the VE/VCO(2)-slope and peak power output as well as peak oxygen uptake solely in patients. We did not observe any association of assessed parameters with disease severity.
  
  
  CONCLUSIONS
  CPET measures indicate ventilatory inefficiency in patients with MDD. The elevated VE/VCO(2)-slope indicates that patients with MDD need to ventilate significantly more to a given amount of developing CO(2). Further investigations are needed to verify the application of the ventilatory classification system to stratify cardiovascular risk in depressive disorder.
authors.affiliation: Department of Sports Medicine, Friedrich-Schiller-University Jena, Woellnitzer Strasse 42, D-07749 Jena, Germany. lars.donath@uni-jena.de
authors.forename: Lars
authors.initials: L
authors.lastname: Donath
authors.forename: Christian
authors.initials: C
authors.lastname: Puta
authors.forename: Silke
authors.initials: S
authors.lastname: Boettger
authors.forename: Hans Josef
authors.initials: HJ
authors.lastname: Mueller
authors.forename: Oliver
authors.initials: O
authors.lastname: Faude
authors.forename: Tim
authors.initials: T
authors.lastname: Meyer
authors.forename: Karl-Jürgen
authors.initials: KJ
authors.lastname: Bär
authors.forename: Holger H W
authors.initials: HH
authors.lastname: Gabriel
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D003865:Major Depressive Disorder / Q000150:complications* / Q000503:physiopathology; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D006333:Heart Failure / Q000503:physiopathology; D006801:Humans; D008875:Middle Aged; D010101:Oxygen Consumption; D011569:Psychiatric Status Rating Scales; D012123:Pulmonary Ventilation; D012044:Regression Analysis; D012131:Respiratory Insufficiency / Q000150:complications* / Q000503:physiopathology; D012307:Risk Factors; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires