title: The association between obesity, mortality and filling pressures in pulmonary hypertension patients; the "obesity paradox".
abstract: BACKGROUND
  The term "obesity paradox", refers to lower mortality rates in obese patients, and is evident in various chronic cardiovascular disorders. There is however, only scarce data regarding the clinical implication of obesity and pulmonary hypertension (PH). Therefore, in the current study, we evaluated the possible prognostic implications of obesity in PH patients.
  
  
  METHODS
  We assessed 105 consecutive PH patients for clinical and hemodynamic parameters, focusing on the possible association between Body Mass Index (BMI) and mortality. Follow-up period was 19 ± 13 months.
  
  
  RESULTS
  Sixty-one patients (58%) had pre-capillary PH and 39 patients (37%) out-of-proportion post-capillary PH. During follow-up period, 30 patients (29%) died. Death was associated with reduced functional-class, inverse-relation with BMI, higher pulmonary artery and right atrial pressures, pulmonary vascular resistance and signs of right ventricular failure. In multivariate analysis, obesity (BMI ≥ 30 kg/m²), was the variable most significantly correlated with improved survival [H.R 0.2, 95% C.I 0.1-0.6; p = 0.004], even after adjustment for baseline characteristics. Obese and very-obese (BMI ≥ 35 kg/m²) patients had significantly less mortality rates during follow-up (12% and 8%, respectively) than non-obese patients (41%), p = 0.01. The tendency of survival benefit for the obese vs. non-obese patients was maintained both in the pre-capillary (10% vs. 46% mortality, p = 0.008) and disproportional post-capillary PH patients (11% vs. 40% mortality, p = 0.04).
  
  
  CONCLUSIONS
  Obesity was significantly associated with lower mortality in both pre-capillary and disproportional post-capillary PH patients. It seems that in PH, similarly to other chronic clinical cardiovascular disease states, there may be a protective effect of obesity, compatible with the "obesity paradox".
authors.affiliation: Department of Cardiovascular Medicine, Lady Davis Carmel Medical Center, and Ruth and Bruce Rappaport School of Medicine, Technion-Israel Institute of Technology, Haifa, Israel. barakzmd@gmail.com
authors.forename: Barak
authors.initials: B
authors.lastname: Zafrir
authors.forename: Yochai
authors.initials: Y
authors.lastname: Adir
authors.forename: Waseem
authors.initials: W
authors.lastname: Shehadeh
authors.forename: Michal
authors.initials: M
authors.lastname: Shteinberg
authors.forename: Nabia
authors.initials: N
authors.lastname: Salman
authors.forename: Offer
authors.initials: O
authors.lastname: Amir
mesh_terms: D000368:Aged; D062185:Atrial Pressure / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D015992:Body Mass Index; D005260:Female; D005500:Follow-Up Studies; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D006976:Hypertension, Pulmonary / Q000150:complications* / Q000503:physiopathology; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications* / Q000503:physiopathology; D011379:Prognosis; D011651:Pulmonary Artery / Q000503:physiopathology; D014655:Vascular Resistance / Q000502:physiology