Survival and cause of death in patients with refractory anemias.

Abstract

7033 Background: Despite its common occurrence, there are few large population-based studies on low-grade myelodysplastic syndromes (MDS). We evaluated the outcomes for the two low-risk MDS subtypes. Methods: The Surveillance, Epidemiology and End Results (SEER) database was searched for patients with refractory anemia (RA) or RA with ringed sideroblasts (RARS), diagnosed between 2001 and 2009 with complete demographic information. Incidence rates were calculated from SEERStat 7.1. Overall survival (OS) and disease-specific survival (DSS) were calculated from diagnosis to death from any cause and death from MDS or acute leukemia, respectively. Univariate survival was estimated by the Kaplan-Meier method and curves compared by log rank. Univariate and multivariable Hazard ratios (HR) were calculated by Cox Proportional Hazards. Results: Among the 6,505 patients who met the inclusion criteria, there were 3,866 (59%) RA and 2,639 (41%) RARS. Age-adjusted incidence rates per 100,000 population for RA and RARS were 0.55 and 0.44 respectively. Medians OS for RA and RARS were 39 and 48 months respectively. Although RARS was associated with improved 5-year OS compared to RA (41.3% vs 37.7%; HR 0.86; 95% CI 0.81-0.92, p < 0.0001), there were no differences in 5-year DSS (74.2% vs 76.3%; HR 1.01, 95% CI 0.90-1.14, p = 0.41). Altogether, 2,112 deaths were accrued among RA patients and 1,352 among the RARS subclass. The number of deaths due to MDS or acute leukemia were 610 (28.8%) in RA and 457 (33.8%) in RARS. Acute leukemia was the cause of death in 190 (9.0%) RA patients and in 143 (10.6%) of RARS patients. Cardiovascular disease accounted for 25% of total deaths in RA and RARS. After adjusted for age, gender, race and year of diagnosis, RARS was associated with increased OS (HR 0.81; 0.76-0.87; p < 0.0001) but not DSS (HR 0.95; 0.84-1.07, p = 0.41). Conclusions: Both RA and RARS are indolent diseases with a high 5-year DSS and death occurring mostly from other causes, particularly cardiovascular disease. Although RARS was associated with better 5-year OS compared to RA, there were no differences in 5-year DSS.