Waiting time and mortality rate on lung transplant candidates in Japan: a single-center retrospective cohort study

Abstract

Background: As lung transplantation (LTX) is a valuable treatment procedure for end-stage pulmonary disease, delayed referral to a transplant center should be avoided. We aimed to conduct a single-center analysis of the survival time after listing for LTX and waitlist mortality in each disease category in a Japanese population.

Methods: We included patients listed for LTX at Tohoku University Hospital from January 2007 to December 2020 who were followed up until March 2021. Pulmonary disease was categorized into the Obstructive, Vascular, Suppurative, Fibrosis, and Allogeneic groups. Risk factors for waitlist mortality were assessed using a Cox proportional hazards model. The Kaplan-Meier method was used to model time to death.

Results: We included 269 LTX candidates. Of those, 100, 72, and 97 patients were transplanted, waiting, and dead, respectively. The median time to LTX and time to death were 796 days (interquartile range [IQR] 579-1056) and 323 days (IQR 129-528), respectively. The Fibrosis group showed the highest mortality (50.9%; p < .001), followed by the Allogeneic (35.0%), Suppurative (33.3%), Vascular (32.1%), and Obstructive (13.1%) groups. The Fibrosis group showed a remarkable risk for waitlist mortality (hazard ratio 3.32, 95% CI 2.11-4.85).

Conclusions: In Japan, the waiting time is extremely long and candidates with Fibrosis have high mortality. There is a need to document outcomes based on the underlying disease for listed LTX candidates to help determine the optimal timing for listing patients based on the estimated local waiting time.

Keywords: Japan; Japan Organ Transplant Network; Lung transplantation; Mortality; Waiting time.

Fig. 1

Study flow

Fig. 2

Kaplan–Meier analysis to model time to waitlist mortality in lung transplant candidates among the five disease categories. The number of patients at risk was depicted below the x-axis (days post-listing)

Fig. 3

Waitlist mortality of lung transplant candidates with Fibrosis. a Kaplan–Meier analysis to model time to waitlist mortality in lung transplant candidates with IPF and non-IPF ILD. The number of patients at risk was depicted below the x-axis (days post-listing). b Proportion of waitlist mortality in lung transplant candidates with IPF stratified according to % predicted FVC. The number of candidates in each category is shown in parentheses. c Pearson correlation coefficient (r) between the % predicted FVC and survival (time to death).

Fig. 4

Transplant indications reported from ISHLT and JSHLT. The proportion of transplant indications for adult LTX candidates between January 1995 and June 2017 stratified according to the ISHLT registry report, as well as in both adult and pediatric LTX candidates between January 1998 and December 2018 stratified according to the JSHLT registry report. Reference at ISHLT [24] and JSHLT [7]