Orthotopic heart transplantation in patients with metabolic risk factors

Background: The aim of this study was to evaluate the impact of metabolic risk factors on mortality rates after orthotopic heart transplantation (OHT).

Methods: Adult patients undergoing OHT between 1998 and 2008 were identified in the United Network for Organ Sharing registry. The impact of metabolic risk factors (hypertension, diabetes mellitus, and obesity) on mortality post-OHT was evaluated in a Cox proportional hazards regression analysis adjusted for other variables associated with survival in univariate analysis (exploratory p value<0.2). Kaplan-Meier survival estimates were compared with the log-rank test.

Results: A total of 15,960 eligible patients underwent OHT during the study period. There were 6,368 (39.9%) patients with none of these risk factors, 6,138 (38.5%) with 1 risk factor, 2,811 (17.6%) with 2 risk factors, and 643 (4.0%) who had all 3 risk factors. After adjusting for other significant variables influencing survival, each individual risk factor independently increased the likelihood of mortality post-OHT (hypertension: HR 1.10 [1.03 to 1.17]; diabetes: HR 1.22[1.13 to 1.31]; obesity: HR 1.17 [1.10 to 1.26], each p<0.01). There was an exponential trend of increasing mortality with the addition of each risk factor (r2=0.99, p<0.001) such that patients with all 3 risk factors had a 63% increased mortality compared with those with no risk factors (HR 1.63 [1.42 to 1.88], p<0.001). There was also a significant trend in declining 5-year survival rates with an increasing number of risk factors: 0 (74.7%), 1 (71.3%), 2 (68.2%), and 3 (63.1%) (p<0.001).

Conclusions: This large-cohort study demonstrates that an increasing number of metabolic risk factors in OHT recipients is associated with exponential increases in postoperative mortality rates.