Racial and Ethnic Disparities Have a Significant Impact on the Outcomes of Patients with Myelodysplastic Syndromes: A Population-Based Study

Background Race and ethnic differences affect the disease characteristics and clinical outcomes in many tumors, including acute myeloid leukemia (Byrne et al. AJCO, 2011). While earlier population-based studies reported no significant impact of race on survival outcomes in myelodysplastic syndromes (MDS) (Ma et al. Cancer, 2007), this study had a limited number of patients, short duration of follow-up including patients diagnosed from 2001-2003 prior to the approval and routine use of hypomethylating agents (HMA). We hypothesized that there are racial differences in the clinical characteristics and outcomes of patients with MDS. We thus analyzed the differences in disease characteristics and survival outcomes based on race and ethnic background in patients with MDS over 13 years. Methods We used the Surveillance, Epidemiology, and End Results (SEER) database to identify adult patients diagnosed with MDS between 2004 and 2016. Disease characteristics and patient outcomes were analyzed among three groups based on race/ethnicity: non-Hispanic white (NHW), non-Hispanic black (NHB) and Hispanics, Fisher exact test and chi-square test were used to compare categorical variables. SEER*Stat version 8.3.6 was used to calculate the incidence rate (IR) and incidence rate ratio (IRR) for NHW, NHB, and Hispanics. Univariate survival analysis was estimated using the Kaplan-Meier method, and groups were compared using a log-rank test. Multivariable survival analyses were performed using the Cox-proportional regression model after adjusting for age, gender, insurance status, histologic risk classification, marital status, and treatment with chemotherapy. Cause-specific survival (CSS) was calculated from the date of diagnosis to the date of MDS-related death and compared amongst the three groups. Results A total of 52,031 patients with MDS were included in this study; 83.4% were NHW, 8.5% were NHB, and 8.2% Hispanics. The incidence was 7.81, 6.46, and 5.17 per 100,000 among NHW, NHB, and Hispanic patients, respectively. Compared to NHW, NHB and Hispanic patients had a significantly lower incidence rate among the overall population (p