Women are less likely to undergo transplants and wait longer. Also, women transplanted with an oversized lung did not show worse survival outcomes, suggesting that size and weight matching may be less stringent in this context.
Study: Increased delay to lung transplantation for women candidates: gender-based disparity matters in the lung transplant trajectory. Image Credit: Golden Dayz/Shutterstock.com
A recent ERJ Open Research study investigated the factors influencing outcome differences between men and women all along the lung transplant (LT) pathway.
Lung transplantation and the role of gender
The field of LT has seen rapid advancements over the last few decades. Surgical techniques, intensive care management, and donor lung utilization and allocation have all improved.
Despite these advances, LT remains fraught with a high mortality and morbidity risk. Understanding key factors such as short—and long-term survival is imperative to predict and potentially improve outcomes.
Gender plays a pivotal role in the field of LT. Recent research has shown that gender differences influence the entire transplantation path, i.e., from waiting list access to post-transplantation outcomes.
Existing LT data from the US shows that women waited longer before transplant, and women had a lower chance of being transplanted than men. Concerning survival post-transplantation, women seem to fare better. However, more studies on varied populations are needed to confirm these results. The literature is also silent on gender heterogeneities both before and after LT.
About the study
The current study used data on French participants extracted from the Cohort in lung transplantation (COLT) database. The objective was to compare men and women at three different periods of the LT process i.e., waiting list, LT itself, and post-transplantation periods, where follow-up was done for up to 10 years.
The data included baseline characteristics such as medical history, pulmonary function tests (PFTs), demographics, and so on.
The underlying diseases were classified as chronic obstructive pulmonary disease (COPD)/emphysema, cystic fibrosis (CF), interstitial lung disease (ILD) (including idiopathic pulmonary fibrosis (IPF)), pulmonary arterial hypertension (PAH), and others.
For every patient, at 3 and 5 years post-LT or at death, the chronic lung allograft dysfunction (CLAD) phenotype was assessed. Lung weight mismatch was calculated as donor weight minus recipient weight. A spline was used to address the non-linear association between overall survival and predicted total lung capacity (pTLC) ratio.
Study findings
The total sample size of 1710 patients included 47% women, and the main underlying disease was COPD/emphysema, followed by ILD and CF. At the time of LT registration, women were younger and presented fewer comorbidities.
Pretransplant anti-HLA antibodies were less prevalent in men for both class I and II. Women were also less likely to be on long-term oxygen therapy.
In the peri-transplantation phase, LT was more often performed in men, i.e., 95.6% versus 91.7% in women. Concerning time on the LT waiting list, women waited for a median of 115 days versus 73 days for men.
Men had more single lung transplantation and less volume reduction than women. Multiple factors had a significant impact on waiting time duration before LT, including gender, age, height, underlying disease, smoking history, and so on.
Factors correlated with a shorter waiting time included listing on the high emergency LT program and male gender. An increased waiting time was associated with the number of pre-transplant class I anti-HLA antibodies and underlying diagnoses of COPD and other diseases.
Women were more frequently transplanted with a male donor than conversely, had a high donor-to-recipient pTLC, received more transplantations with lungs weighing more than 15 kg, and showed higher survival rates post LT. In women, survival at 1 year, 3 years, and 5 years post-LT was 83%, 73%, and 70%.
The figures for men were 79%, 69%, and 61%, respectively. There was no significant gender difference in CLAD prevalence. The main causes of death in both groups were graft failure and infection. Furthermore, there was no difference in bacterial, fungal, or viral infection, but men reported cancer more frequently post-LT.
Multiple factors were associated with post-LT survival, such as the age of the recipient and donor, gender, and donor-recipient pTLC ratio. In multivariable analysis, the factors identified for low survival post-LT were single lung transplantation, male gender, history of ischemic heart disease, COPD, and so on.
Post-LT survival was not significantly different according to donor gender, but this was not the case for recipient gender. Even in the case of gender mismatch, a higher survival was noted in female recipients.
For survival, weight-positive mismatch (donor weight - recipient weight > 15 kg) did not have an impact, but weight-negative mismatch (donor weight - recipient weight < -15 kg) had a negative effect. A significantly lower survival for male recipients with COPD was noted.
Conclusions
In sum, this study highlighted that women waited significantly longer for a LT and were less likely to be transplanted than men.
Furthermore, the survival outcomes when women received an oversized lung were not worse than men, suggesting that weight mismatch and size matching criteria may be less stringent in this context.
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