Socioeconomic Status Influences Long-Term Outcomes in 1-Year Survivors after Allogeneic Hematopoietic Cell Transplantation

Allogeneic hematopoietic cell transplantation (allo HCT) survivors are at risk for long-term mortality from late complications. Low socioeconomic status (SES) has been shown to be associated with health care disparities including poor access and adverse outcomes in a variety of health conditions. Early post-transplant care is typically well coordinated through the patients transplant center. However, as patients transition back to their community providers, it is possible that patients with less resources and poor access to healthcare would be at higher risk for complications and mortality. Hence, we hypothesized that SES would be associated with survival and non-relapse mortality (NRM) in long-term survivors after allo HCT. We studied 283 consecutive allo HCT recipients transplanted between 2003 and 2012 who had survived for at least 1 year in remission. Median annual household income was estimated using Census tract data and from ZIP code of residence at the time of transplant. SES categories were determined by recursive partitioning analysis and were categorized into low SES (<$51,000/yr, N=203) and high SES (≥$51,000/yr, N=80). Low SES patients were more likely to be of non-White race (10% vs. 1%), otherwise there were no notable differences between the two cohorts, including diagnosis, disease status, HCT-Comorbidity Index scores, donor source, graft source and conditioning regimen intensity. In univariate analysis, low SES patients had significantly worse survival (figure) and NRM but comparable incidence of relapse mortality. In multivariate analyses that adjusted for patient, disease and transplant characteristics, patients with low SES had significantly higher risks of all-cause mortality (HR 1.98, 95% CI 1.16-3.37, p=0.012) and NRM (HR 2.22, 95% CI 1.09-4.50, p=0.028), but similar risks of relapse mortality (HR 1.01, 95% CI 0.44-2.34, p=0.97) compared to high SES patients. Common causes of death in low SES and high SES patients included disease relapse (39% vs 47%), infections (20% vs 12%), organ toxicity (17% vs 18%) and chronic graft-versus-host disease (11% vs 18%). In conclusion, 1 year allo HCT survivors with low SES have inferior overall survival that is driven by higher NRM compared to patients with high SES. More research is needed to understand the reasons for these health care disparities and identify interventions to mitigate them.

Figure: Overall survival by SES in 1 year allogeneic HCT survivors