Modeling the effects of functional performance and post-transplant comorbidities on health-related quality of life after heart transplantation

Abstract

Background: Health-related quality of life and functional performance are important outcome measures following heart transplantation. This study investigates the impact of pre-transplant functional performance and post-transplant rejection episodes, obesity and osteopenia on post-transplant health-related quality of life and functional performance.

Methods: Functional performance and health-related quality of life were measured in 70 adult heart transplant recipients. A composite health-related quality of life outcome measure was computed via principal component analysis. Iterative, multiple regression-based path analysis was used to develop an integrated model of variables that affect post-transplant functional performance and health-related quality of life.

Results: Functional performance, as measured by the Karnofsky scale, improved markedly during the first 6 months post-transplant and was then sustained for up to 3 years. Rejection Grade > or =2 was negatively associated with health-related quality of life, measured by Short Form-36 and reversed Psychosocial Adjustment to Illness Scale scores. Patients with osteopenia had lower Short Form-36 physical scores and obese patients had lower functional performance. Path analysis demonstrated a negative direct effect of obesity (beta = - 0.28, p < 0.05) on post-transplant functional performance. Post-transplant functional performance had a positive direct effect on the health-related quality of life composite score (beta = 0.48, p < 0.001), and prior rejection episodes grade > or =2 had a negative direct effect on this measure (beta = -0.29, p < 0.05). Either directly or through effects mediated by functional performance, moderate-to-severe rejection, obesity and osteopenia negatively impact health-related quality of life. These findings indicate that efforts should be made to devise immunosuppressive regimens that reduce the incidence of acute rejection, weight gain and osteopenia after heart transplantation.