title: Prognostic value of body mass index in transcatheter aortic valve implantation: A "J"-shaped curve.
abstract: OBJECTIVE
  We aimed to determine whether body mass index (BMI) is a prognostic indicator for long-term, all-cause mortality in patients undergoing transcatheter aortic valve implantation (TAVI).
  
  
  BACKGROUND
  Obesity in patients with established cardiovascular disease has previously been identified as an indicator of good prognosis, a phenomenon known as the "obesity paradox". The prognostic significance of BMI in patients with severe aortic stenosis (AoS) undergoing TAVI is a matter of current debate, as published studies are scarce and their results conflicting.
  
  
  METHODS
  This is an observational, retrospective study involving 770 patients who underwent TAVI for AoS. The cohort was divided into three groups based on their BMI: normal weight (≥18.5 to <25kg/m2), overweight (≥25 to <30kg/m2) and obese (≥30kg/m2). The predictive effect of BMI on all-cause mortality 3years following TAVI intervention was analysed using a Cox regression.
  
  
  RESULTS
  155 patients died during follow-up. The overweight group (n=302, 38.97%), experienced a lower mortality rate compared to the normal weight and obese groups (15.9% vs 25.7% and 21.0%, respectively [log-rank p-value=0.036]). After adjustment by logistic EuroSCORE, being overweight was found to be an independent protective factor against mortality (HR: 0.63 [95% CI: 0.42 to 0.94], p=0.024). This was not the case for obesity (HR: 0.92 [95% CI: 0.63 to 1.35], p=0.664). We therefore describe for the first time, a "J-shaped" regression curve describing the relationship between BMI and mortality.
  
  
  CONCLUSIONS
  BMI is a predictive factor of all-cause mortality in AoS patients undergoing TAVI. This relationship takes the form of a "J-shaped" curve in which overweight patients are associated with the lowest mortality rate at follow-up.
authors.affiliation: Complexo Hospitalario Universitario de Santiago de Compostela, A Coruña, Spain; CIBER Cardiovascular (CIBERCV), Spain. Electronic address: ferreiro_44@hotmail.com.
authors.forename: Rocío
authors.initials: R
authors.lastname: González-Ferreiro
authors.affiliation: Hospital Clínico Universitario Virgen de la Victoria de Málaga, Spain.
authors.forename: Antonio J
authors.initials: AJ
authors.lastname: Muñoz-García
authors.affiliation: Complexo Hospitalario Universitario de Santiago de Compostela, A Coruña, Spain.
authors.forename: Diego
authors.initials: D
authors.lastname: López-Otero
authors.affiliation: Hospital Universitario Central de Asturias, Oviedo, Spain.
authors.forename: Pablo
authors.initials: P
authors.lastname: Avanzas
authors.affiliation: Hospital Universitario Central de Asturias, Oviedo, Spain.
authors.forename: Isaac
authors.initials: I
authors.lastname: Pascual
authors.affiliation: Hospital Clínico Universitario Virgen de la Victoria de Málaga, Spain.
authors.forename: Juan H
authors.initials: JH
authors.lastname: Alonso-Briales
authors.affiliation: Complexo Hospitalario Universitario de Santiago de Compostela, A Coruña, Spain; CIBER Cardiovascular (CIBERCV), Spain.
authors.forename: Ramiro
authors.initials: R
authors.lastname: Trillo-Nouche
authors.affiliation: Hospital Universitario Central de Asturias, Oviedo, Spain.
authors.forename: Federico
authors.initials: F
authors.lastname: Pun
authors.affiliation: Hospital Clínico Universitario Virgen de la Victoria de Málaga, Spain.
authors.forename: Manuel F
authors.initials: MF
authors.lastname: Jiménez-Navarro
authors.affiliation: Hospital Clínico Universitario Virgen de la Victoria de Málaga, Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: Hernández-García
authors.affiliation: Hospital Universitario Central de Asturias, Oviedo, Spain.
authors.forename: César
authors.initials: C
authors.lastname: Morís
authors.affiliation: Complexo Hospitalario Universitario de Santiago de Compostela, A Coruña, Spain; CIBER Cardiovascular (CIBERCV), Spain.
authors.forename: José R
authors.initials: JR
authors.lastname: González Juanatey
mesh_terms: D001024:Aortic Valve Stenosis / Q000150:complications / Q000401:mortality / Q000601:surgery*; D015992:Body Mass Index; D002423:Cause of Death / Q000639:trends; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D050177:Overweight / Q000150:complications* / Q000453:epidemiology; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology; D015996:Survival Rate / Q000639:trends; D013997:Time Factors; D065467:Transcatheter Aortic Valve Replacement / Q000379:methods*
keywords: Aortic stenosis; Body mass index; Mortality; Obesity paradox; Transcatheter aortic valve implantation