Association of Socioeconomic Status (SES) with Outcomes of Autologous Hematopoietic Cell Transplantation (ASCT) for Lymphoma

Healthcare disparities, such as race/ethnicity and SES, can impact access to care and outcomes in cancer patients. ASCT is standard therapy for high-risk relapsed and refractory lymphoma, but is a highly specialized and resource-intensive procedure. The association of race and SES with outcomes in lymphoma patients undergoing ASCT has not been described previously. We conducted a retrospective cohort study of 687 consecutive ASCT recipients with Hodgkins (N=154, 22%) and non-Hodgkins (N=533, 78%) lymphoma transplanted between 2003 and 2013 at our institution. Zip code of residence was used to obtain median annual household income based on 2010 US Census data. Patients were categorized into low SES (<$50,000/yr) and high SES (≥$50,000/yr) based on the household income cutpoint identified by recursive partitioning analysis for predicting survival. Low SES patients were significantly more likely to live further away from our center (median 54 vs 28 miles), belong to non-White racial group (12% vs 3%), have lower performance status score (4% vs 1% with ECOG >1/KPS <80), and have high disease risk at ASCT (9% vs 5%). Patient, disease and transplant characteristics were otherwise comparable. 93% patients received a conditioning regimen consisting of high-dose busalfan, cyclophosphamide and etoposide. Median followup was 53 months. In univariate analysis, low SES patients had significantly higher relapse mortality and lower overall survival (OS) and progression-free survival (PFS) (see table and figures). This was confirmed on multivariable analysis for relapse mortality (for high SES vs. low SES: HR 0.74 [95% CI, 0.54-0.99], P=0.05), OS (HR 0.74 [0.58-0.95], P=0.02) and PFS (HR 0.77 [0.63-0.95], P=0.02). We also conducted an analysis in the subgroup of patients who had survived in remission for ≥1-year post-HCT to investigate whether SES was associated with outcomes following transition from transplant center to community providers (see table and figures). Interestingly, in multivariable analysis, high SES patients had better OS (HR 0.73, P=0.05 vs low SES) that was primarily driven by a lower risk of NRM (HR 0.62, P=0.06). We did not observe any association between race/ethnicity and distance from transplant center with ASCT outcomes in multivariable analysis that included all recipients or in the analysis limited to 1-year survivors. In conclusion, lower SES is associated with poor survival in patients receiving ASCT for lymphoma. Low SES patients have higher risks of relapse related mortality compared to high SES patients. In patients surviving in remission for >1 year, however, mortality in the low SES group in primarily mediated through non-relapse causes. Our study highlights the need for active interventions to mitigate health care disparities in this high risk population.

Table: 5-year outcomes after ASCT for lymphoma by SES

 

Outcomes	All patients, N=687			1-yr survivors, N=551
	Low SES	High SES	P-value	Low SES	High SES	P-value
Relapse mortality	29%	25%	0.03	16%	18%	0.53
NRM	16%	12%	0.18	14%	9%	0.07
OS	55%	64%	0.004	70%	74%	0.07
PFS	41%	47%	0.01	57%	58%	0.25

Figures: OS for all patients and 1-year survivors