Holmqvist AS, et al. - Researchers assessed cause-specific late mortality among individuals who have lived 2 years or more after allogeneic blood or marrow transplantation (BMT) performed in childhood. They also determined if rates of late mortality have changed over time. During the past 3 decades, a decrease in late mortality has been observed among children who had allogeneic BMT. However, an elevated risk of late mortality was observed in these patients even 25 years or more after transplantation when compared with the general population, necessitating lifelong follow-up.

Methods

• In this retrospective cohort study performed between January 1, 1974, and December 31, 2010, individuals who lived 2 years or more after undergoing allogeneic BMT performed in childhood were examined.
• Follow-up was performed until December 31, 2016.
• All-cause mortality, relapse-related mortality, and non–relapse-related mortality were assessed.
• Using the National Death Index Plus Program, Accurint databases, and medical records, data on vital status and causes of death were collected.

Results

• According to data, the median age at transplantation was 14.6 years (range, 0-21 years) among 1,388 individuals (559 females and 829 males) who lived 2 years or more after allogeneic BMT performed in childhood.
• A total of 295 deaths occurred, yielding an overall survival rate of 79.3% at 20 years after BMT.
• Infection and/or chronic graft-vs-host disease (121 of 244 [49.6%]), primary disease (60 of 244 [24.6%]), and subsequent malignant neoplasms (45 of 244 [18.4%]) were documented as the leading causes of death.
• In comparison with the general population, a 14.4-fold increased risk for death (95% CI, 12.8-16.1) was reported in the cohort (292 deaths observed; 20.3 deaths expected).
• At 25 years or more after BMT, relative mortality remained elevated (standardized mortality ratio, 2.9; 95% CI, 2.0-4.1).
• The estimated absolute excess risk for death from any cause was 12.0 per 1,000 person-years (95% CI, 10.5-13.5).
• Throughout follow-up, the cumulative incidence of relapse-related mortality was exceeded by the cumulative incidence of non–relapse-related mortality.
• A decrease in the 10-year cumulative incidence of late mortality over time was reported (before 1990, 18.9%; 1990-1999, 12.8%; 2000-2010, 10.9%; P=.002); statistical significance of this decrease persisted even after adjusting for demographic and clinical factors (referent group: <1990; 1990-1999: hazard ratio, 0.64; 95% CI, 0.47-0.89; P=.007; 2000-2010: hazard ratio, 0.49; 95% CI, 0.31-0.76; P=.002; P< .001 for trend).