Abstract
BACKGROUND: Single lung transplantation (SLT) and double lung transplantation (DLT) are associated with differences in morbidity and mortality, although the effects of transplant type on patient-reported outcomes are not widely reported and conclusions have differed. Previous studies compared mean health-related quality of life (HRQOL) scores but did not evaluate potentially different temporal trajectories in the context of longitudinal follow-up. To address this uncertainty, this study was designed to evaluate longitudinal HRQOL after SLT and DLT with the hypothesis that temporal trajectories differ between SLT and DLT. METHODS: Patients transplanted at a single institution were eligible to be surveyed at 1 month, 3 months, 6 months, and then annually after transplant using the Short Form 36 Health Survey, with longitudinal physical component summary (PCS) and mental component summary (MCS) scores as the primary outcomes. Multivariable mixed-effects models were used to evaluate the effects of transplant type and time posttransplant on longitudinal PCS and MCS after adjusting age, diagnosis, rejection, Lung Allocation Score quartile, and intubation duration. Time by transplant type interaction effects were used to test whether the temporal trajectories of HRQOL differ between SLT and DLT recipients. HRQOL scores were referenced to general population norms (range, 40 to 60; mean, 50 ± 10) using accepted standards for a minimally important difference (½ SD, 5 points). RESULTS: Postoperative surveys (n = 345) were analyzed for 136 patients (52% male, 23% SLT, age 52 ± 13 years, LAS 42 ± 12, follow-up 37 ± 29 months [range, 0.6 to 133]) who underwent lung transplantation between 2005 and 2016. After adjusting for model covariates, overall posttransplant PCS scores have a significant downward trajectory (p = 0.015) whereas MCS scores remain stable (p = 0.593), with both averaging within general population norms. The time by transplant type interaction effect (p = 0.002), however, indicate that posttransplant PCS scores of SLT recipients decline at a rate of 2.4 points per year over the total observation period compared to DLT. At approximately 60 months, the PCS scores of SLT recipients, but not DLT recipients, fall below general population norms. CONCLUSIONS: The trajectory of physical HRQOL in patients receiving SLT declines over time compared with DLT, indicating that, in the longer term, SLT recipients are more likely to have physical HRQOL scores that fall substantively below general population norms. Physical HRQOL after 5 years may be a consideration for lung allocation and patient counseling regarding expectations when recommending SLT or DLT.