title: Donor-recipient size matching and mortality in heart transplantation: Influence of body mass index and gender.
abstract: BACKGROUND
  The International Society for Heart and Lung Transplantation (ISHLT) guidelines advise against inappropriate weight match (IWM) for heart transplant, defined as donor weight <70% of recipient's weight. Few studies have explored in detail this size-matching recommendation, especially with regard to body mass index (BMI) and gender matching. We aimed to determine whether any difference could be observed between size-matching in obese and non-obese recipients with regard to mortality after cardiac transplantation.
  
  
  METHODS
  Data from 52,455 adult heart transplants (recipients ≥18 years of age) between 1994 and 2013 were obtained from the ISHLT Registry. We defined the following subgroups of patients based on BMI: underweight, BMI <18.5; non-obese, BMI 18.5 to 30; and obese, BMI >30. The end-points were all-cause 30-day mortality and cumulative mortality.
  
  
  RESULTS
  IWM was associated with increased 30-day mortality (odds ratio [OR] = 1.20, 95% confidence interval [CI] 1.01 to 1.43, p = 0.041) and cumulative mortality (hazard ratio [HR] = 1.14, 95% CI 1.07 to 1.22, p < 0.001). In non-obese recipients, IWM was associated with increased 30-day mortality (OR = 1.89, 95% CI 1.48 to 2.41, p < 0.001) as well as cumulative mortality (HR = 1.27, 95% CI 1.15 to 1.41, p < 0.001), whereas, for obese recipients, IWM was not associated with 30-day or cumulative mortality. Male recipients of female allografts (HR = 1.08, 95% CI 1.04 to 1.12, p < 0.001) as well as female recipients of male allografts (HR = 1.07, 95% CI 1.02 to 1.13, p = 0.003) had increased cumulative mortality compared with gender-matched transplants. There was no interaction between IWM and gender mismatch.
  
  
  CONCLUSIONS
  Our results indicate that donor weight <70% of recipient weight increases mortality in non-obese heart transplant recipients, but not in obese transplant recipients. Gender mismatch increases mortality independently of weight match.
authors.affiliation: Department of Clinical Sciences Lund, Cardiothoracic Surgery, Lund University and Skåne University Hospital, Lund, Sweden.
authors.forename: Henrik
authors.initials: H
authors.lastname: Bergenfeldt
authors.affiliation: Division of Cardiovascular Medicine, University of Utah School of Medicine, Salt Lake City, Utah, USA; International Society for Heart and Lung Transplantation, Dallas, Texas, USA.
authors.forename: Josef
authors.initials: J
authors.lastname: Stehlik
authors.affiliation: Department of Laboratory Medicine, Lund, Clinical Chemistry and Pharmacology, Lund University and Skåne University Hospital, Lund, Sweden; and.
authors.forename: Peter
authors.initials: P
authors.lastname: Höglund
authors.affiliation: Department of Clinical Sciences Lund, Surgery, Lund University and Skåne University Hospital, Lund, Sweden.
authors.forename: Bodil
authors.initials: B
authors.lastname: Andersson
authors.affiliation: Department of Clinical Sciences Lund, Cardiothoracic Surgery, Lund University and Skåne University Hospital, Lund, Sweden. Electronic address: johan.nilsson@med.lu.se.
authors.forename: Johan
authors.initials: J
authors.lastname: Nilsson
mesh_terms: D000328:Adult; D015992:Body Mass Index; D001835:Body Weight; D005260:Female; D016027:Heart Transplantation / Q000379:methods / Q000401:mortality*; D006801:Humans; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D011379:Prognosis; D016016:Proportional Hazards Models; D012042:Registries; D012189:Retrospective Studies; D012737:Sex Factors; D016019:Survival Analysis; D013548:Sweden; D009927:Tissue and Organ Procurement; D066027:Transplant Recipients; D016896:Treatment Outcome
keywords: body mass index; gender-matching; heart transplantation; obesity; size matching; survival