The Impact of Marital Status on Hematopoietic Stem Cell Transplant (HCT) Recipient Outcomes: A Surrogate for Consistent Caregiver. a CIBMTR Registry Study

Background

Current literature suggests that the presence and quality of social support may provide meaningful benefits in overall survival of HCT recipients. Further, studies in general oncology and renal transplantation population suggest that married patients have favorable outcomes. Caregivers of HCT recipients are an important source of both instrumental and emotional support, and a reasonable surrogate for presence of social support. Using data from Center for International Blood and Marrow Transplant Research (CIBMTR), we examined the potential influence of marital status (surrogate for caregiver) at the time of HCT on outcomes of HCT.

Methods

Patients, >40 years of age who underwent either autologous or allogeneic-HCT from 2008 to 2015 were included. Marital status was defined as either 1) Married, 2) Single, never married, 3) Separated/divorced, and 4) Widowed. The probability of OS at 5 years, Grade 2-4 acute GVHD at 100 days and chronic GVHD at 2 years were estimated as appropriate using the Kaplan-Meier method with the log-rank test used for univariate comparisons. Multivariate analysis was performed to determine the association of marital status with these outcomes, while adjusting for clinical and sociodemographic variables.

Results

We identified 10,226 allogeneic and 5,714 autologous HCT patients; the median follow-up of survivors was 37 months (range 1-102 months) and 40 months (range 1-106 months) respectively. In the allogeneic population, there were n=7,999 married, n=741 single, n=1,175 separated/divorced and n=311 widowed patients. There were n=4,308, n=478, n=695 and n=233 respectively in the autologous population. The baseline characteristics amongst the 4 groups of marital status were comparable. In the allogeneic population, the 5-year probability of OS, 100-day Grade 2-4 acute GVHD, 2-year probability of chronic GVHD were 38% [95%CI (36-39%)], 16% [95%CI (15-17%)]and 46% [95%CI (45-47%)] respectively; while the 5-year probability of OS in the autologous population was 63% [95%CI (61-64%)].

When compared with married patients, single, separated/divorced and widowed patients were not at an increased risk of death [HR 1.09, 95%CI (0.98-1.2); HR 1.01, 95%CI (0.93-1.09); HR 1.09, 95%CI (0.98-1.2)] in the allogeneic setting. Similarly, there was no association of marital status and OS in the autologous setting [HR 1.10, 95%CI (0.92-1.33); HR 1.17, 95%CI (1.01-1.36); HR 1.08, 95%CI (0.86-1.37)] respectively. In contrast, marital status in the allogeneic setting was associated with an increased risk of grade 2-4 acute GVHD in patients who are divorced/separated as compared to married patients [HR 1.13, 95%CI (1.03-1.24)] but not chronic GVHD [HR 0.90, 95%CI (0.80-1.02); HR 0.94, 95%CI (0.86-1.04); HR 0.82, 95%CI (0.68-0.99)] respectively. We did not identify an interaction between marital status and gender.

Conclusions

Our data suggest the marital status in patients undergoing either autologous or allogeneic HCT is not associated with overall survival or chronic GVHD, while the risk of acute GVHD maybe increased in patients who are divorced/separated. Taken together, the effect of marital status on post-HCT outcomes is negligible when other patient, disease and transplant variables are considered. Alternatively, marital status maybe an imperfect marker for positive social support. Future research should consider measuring social support using validated scales and assess health related quality of life together with health care utilization outcomes to better appreciate the potential impact of social support.