Trends in underlying causes of death in allogeneic hematopoietic cell transplant recipients over the last decade.

OBJECTIVES: Improved survival after hematopoietic cell transplantation (HCT) and an increasingly comorbid transplant population may give rise to new trends in the causes of death. METHODS: This study includes all adult allogeneic HCT recipients transplanted at Rigshospitalet between January 1, 2010 and December 31, 2019. Underlying causes of death were determined using the Classification of Death Causes after Transplantation (CLASS) method. RESULTS: Among 802 HCT recipients, 289 died during the study period. The main causes of death were relapse (N = 133, 46.0%), graft-versus-host disease (GvHD) (N = 64, 22.1%) and infections (N = 35, 12.1%). Multivariable analyses showed that with increasing transplant calendar year, a decreased risk of all-cause mortality (HR 0.92, 95% CI 0.87-0.97) and death from GvHD (HR 0.87, 95% CI 0.78-0.97) was identified, but not for other specific causes. Standardized mortality ratios (SMRs) for all-cause mortality decreased from 23.8 (95% CI 19.1-28.5) to 18.4 (95% CI 15.0-21.9) for patients transplanted in 2010-2014 versus 2015-2019, while SMR for patients who died from GvHD decreased from 8.19 (95% CI 5.43-10.94) to 3.65 (95% CI 2.13-5.18). CONCLUSIONS: As risk of all-cause mortality and death from GvHD decreases, death from relapse remains the greatest obstacle in further improvement of survival after HCT.

Trends in underlying causes of death in solid organ transplant recipients between 2010 and 2020: Using the CLASS method for determining specific causes of death.

Monitoring specific underlying causes of death in solid organ transplant (SOT) recipients is important in order to identify emerging trends and health challenges. This retrospective cohort study includes all SOT recipients transplanted at Rigshospitalet between January 1st, 2010 and December 31st, 2019. The underlying cause of death was determined using the newly developed Classification of Death Causes after Transplantation (CLASS) method. Cox regression analyses assessed risk factors for all-cause and cause-specific mortality. Of the 1774 SOT recipients included, 299 patients died during a total of 7511 person-years of follow-up (PYFU) with cancer (N = 57, 19%), graft rejection (N = 55, 18%) and infections (N = 52, 17%) being the most frequent causes of death. We observed a lower risk of all-cause death with increasing transplant calendar year (HR 0.91, 95% CI 0.86-0.96 per 1-year increase), alongside death from graft rejection (HR 0.84 per year, 95% CI 0.74-0.95) and death from infections (HR 0.86 per year, 95% CI 0.77-0.97). Further, there was a trend towards lower cumulative incidence of death from cardiovascular disease, graft failure and cancer in more recent years, while death from other organ specific and non-organ specific causes did not decrease. All-cause mortality among SOT recipients has decreased over the past decade, mainly due to a decrease in graft rejection- and infection-related deaths. Conversely, deaths from a broad range of other causes have remained unchanged, suggesting that cause of death among SOT recipients is increasingly diverse and warrants a multidisciplinary effort and attention in the future.

Classification of death causes after transplantation (CLASS): Evaluation of methodology and initial results.

Correct classification of death causes is an important component of transplant trials.We aimed to develop and validate a system to classify causes of death in hematopoietic stem cell (HSCT) and solid organ (SOT) transplant recipients.Case record forms (CRF) of fatal cases were completed, including investigator-designated cause of death. Deaths occurring in 2010 to 2013 were used for derivation; and were validated by deaths occurring in 2013 to 2015. Underlying cause of death (referred to as recorded underlying cause) was determined through a central adjudication process involving 2 external reviewers, and subsequently compared with the Danish National Death Cause Registry.Three hundred eighty-eight recipients died 2010 to 2015 (196 [51%] SOT and 192 [49%] HSCT). The main recorded underlying causes of death among SOT and HSCT were classified as cancer (20%, 48%), graft rejection/failure/graft-versus-host-disease (35%, 28%), and infections (20%, 11%). Kappa between the investigator-designated and the recorded underlying cause of death was 0.74 (95% CI 0.69-0.80) in derivation and comparable in the validation cohort. Death causes were concordant with the Danish National Death Cause Registry in 37.2% (95% CI 31.5-42.9) and 38.4% (95% CI 28.8-48.0) in the derivation and validation cohorts, respectively.We developed and validated a method to systematically and reliably classify the underlying cause of death among transplant recipients. There was a high degree of discordance between this classification and that in the Danish National Death Cause Registry.