Youngest, oldest adults experience lowest survival rate after lung transplantation
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Age appears to be “the most reliable and important risk factor” for mortality after lung transplantation among U.S. adults, according to data published in Chest.
“The age of lung transplant patients continues to increase in the U.S.; however, clinicians had conflicting findings in the scientific literature about the impact of age on survival after lung transplantation. In the past decade, the proportion of patients aged 65 years and older has increased from 14.6% of recipients in 2008 to 30.1% in 2017. Multiple U.S. and international studies demonstrated increased posttransplant mortality among older lung transplant recipients, but others did not,” Maryam Valapour, MD, MPP, director of the lung transplant outcomes at Cleveland Clinic and senior lung transplant investigator for the U.S. Scientific Registry of Transplant Recipients (SRTR), wrote in an email to Healio Pulmonology.
“The problem with many of the prior analyses was that they were limited by their design. These designs did not account for center-specific practice variation, used variable age classification and had measurements spanning changes in lung allocation systems. We sought to resolve these methodologic issues to definitively answer the question of impact of age on survival after lung transplant,” she said.
Using data from the SRTR, Valapour and colleagues identified all lung transplant recipients aged at least 18 years between 2006 and 2015. Of the 14,253 patients included in the analysis, 7.7% were younger than 30 years, 29.5% were aged 30 to 55 years and 62.8% were older than 55 years, with a median age at transplant of 59 years and a median posttransplant survival of 5.6 years.
Of all factors analyzed, age emerged as the most significant risk factor for death at all timepoints after transplant, with the youngest and oldest having worse survival than middle-aged patients. In a risk-adjusted model for a hypothetical patient with median values for all model variables, 1-year predicted survival was 93.9% for a patient aged 20 years, 96.1% for a patient aged 45 years and 92.8% for a patient aged 65 years. Similarly, 5-year predicted survival was 64.5% for a patient aged 20 years, 81.2% for a patient aged 45 years and 71.5% for a patient aged 65 years.
These findings, Valapour noted, were somewhat surprising.
“While we expected to find that older patients have decreased survival after transplant, our observation of decreased survival in younger adult recipients was not expected,” she said.
Parametric and nonparametric modeling also identified age as the most important risk factor for survival after transplant and the interaction between age and risk factors for death suggested that age improves the predictive ability of most variables.
In addition to age, risk factors for death for all patients included higher creatinine, single lung transplant, hospitalization before transplant and increased bilirubin.
Valapour said the clinical importance of these findings is twofold.
“First, it will help clinicians inform patients more accurately about their expected survival after transplant, allowing patients to make more informed decisions. Second, clinicians can use our finding that risk factors for death differ by age to identify and intervene in a targeted way to improve survival after transplant for all patients,” she told Healio Pulmonology.
Notably, the researchers also found that risk factors associated with death varied across age categories, but social determinants, including lower education and government insurance, disproportionately affected patients younger than 30 years.
“It is important to better understand how social determinants of health play such a significant role in the mortality for our young patients,” Valapour said. – by Melissa Foster
For more information:
Maryam Valapour, MD, MPP, can be reached at valapom@ccf.org; Twitter: @MValapour.
Disclosure: Valapour reports no relevant financial disclosures.