Socioeconomic Differences in Patient Survival Are Increasing for Acute Myeloid Leukemia and Multiple Myeloma in Sweden

Abstract

Purpose An association between socioeconomic status (SES) and survival in acute myeloid leukemia (AML) and multiple myeloma (MM) has not been established in developed countries. We assessed the impact of SES on survival in two large population-based cohorts of AML and MM patients diagnosed in Sweden 1973 to 2005. Patients and Methods The relative risk of death (all cause and cause specific) in relation to SES was estimated using Cox's proportional hazards regression. We also conducted analyses stratified by calendar periods (1973 to 1979, 1980 to 1989, 1990 to 1999, and 2000 to 2005). Results We identified a total of 9,165 and 14,744 patients with AML and MM, respectively. Overall, higher white-collar workers had a lower mortality than other SES groups for both AML (P = .005) and MM (P < .005). In AML patients, a consistently higher overall mortality was observed in blue-collar workers compared with higher white-collar workers in the last three periods (hazard ratio [HR], 1.26; 95% CI, 1.05 to 1.51; HR, 1.23; 95% CI, 1.05 to 1.45; HR, 1.28; 95% CI, 1.04 to 1.57, respectively). In MM, no difference was observed in the first two calendar periods. However, in 1990 to 1999, self-employed (HR, 1.18; 95% CI, 1.02 to 1.37), blue-collar workers (HR, 1.18; 95% CI, 1.04 to 1.32), and retired (HR, 1.45; 95% CI, 1.16 to 1.80) had a higher mortality compared to higher white-collar workers. In 2000 to 2005, blue-collar workers had a higher mortality (HR, 1.31; 95% CI, 1.07 to 1.60) compared with higher white-collar workers. Conclusion SES was significantly associated with survival in both AML and MM. Most conspicuously, a lower mortality was observed among the highest SES group during more recent calendar periods. Differences in management, comorbidity, and lifestyle, are likely factors to explain these findings.