African Americans in VA system demonstrate better multiple myeloma outcomes than Caucasians
African American patients with multiple myeloma demonstrated superior OS compared with Caucasian patients in a VA setting with equal treatment access, according to a study published in Blood.
Multiple myeloma, which accounts for 1.8% of malignancies in the U.S., is more common among African Americans than Caucasians, according to study background.
“Recent studies have found significant and increasing racial disparities in OS since the introduction of high-dose and novel agent-based therapies,” Nathanael R. Fillmore, associate director for machine learning and predictive analytics at Massachusetts Veterans Epidemiology Research and Information Center of VA Boston Healthcare System and instructor in medicine at Harvard Medical School, and colleagues wrote. “Limited access to novel therapies has been considered partly responsible for the lower OS in African Americans, and a number of studies have reported such racial disparity in the utilization of both novel therapies and transplant.”
Fillmore and colleagues identified 15,717 patients with multiple myeloma who received treatment in the VA health care system between 2000 and 2017. The study population included 3,254 African Americans (median age at diagnosis, 65.5 years; 96.6% men) and 8,845 Caucasians (median age at diagnosis, 70.1 years; 98.3% men).
Median OS was 4.62 years (95% CI, 4.5-4.74).
The researchers found that age at diagnosis was a significant factor in OS; median OS declined from 7.5 years among patients diagnosed in their 40s to 5.9 years for those diagnosed in their 50s, 5.2 years for those diagnosed in their 60s, 3.5 years for those diagnosed in their 70s, and 2.6 years for those diagnosed in their 80s (P < .001).
Results of an analysis by race showed median OS of 5.07 years (95% CI, 4.7-5.44) among African Americans vs. 4.52 years (95% CI, 4.38-4.65) among Caucasians (P < .001).
In an analysis stratified by age at diagnosis, African American patients aged younger than 65 years demonstrated significantly higher median OS (7.07 years; 95% CI, 6.36-7.7) than Caucasians (5.83 years; 95% CI, 5.44-6.09; P < .001). Patients aged 65 years or older had comparable median OS across race (3.69 years for African Americans vs. 4.04 years for Caucasians).
A Cox analysis including age as a continuous-time covariate showed African American patients aged younger than 65 years had a significant reduction in age-adjusted risk for death than Caucasian patients (HR = 0.86; 95% CI, 0.79-0.94). Researchers observed no significant difference in age-adjusted risk for death by race among patients aged 65 years or older (HR = 1.05; 95% CI, 0.98-1.13).
To assess the possible influence of health care access on this patient population, the researchers examined use of new agents and stem cell transplantation. They found no racial disparity at the VA in terms of overall use of novel therapies, including immunomodulatory or proteasome agents, with similar proportions of African Americans and Caucasians receiving these therapies at induction (82.5% vs. 81.5%) and over a lifetime (90.8% vs. 90.2%). Stem cell transplantation rates also appeared similar between the racial groups (10.1% vs. 9.1%).
Researchers did, however, observe significant differences between races in of the type of novel agent used. Bortezomib (Velcade, Millennium/Takeda), with and without lenalidomide (Revlimid, Celgene), was more frequently used among African Americans, whereas thalidomide (Thalomid, Celgene) was more prevalent among Caucasians. However, researchers could not attribute the superior survival among younger African Americans vs. Caucasians to any of these differences.
A multivariate Cox analysis confirmed the independent association of African American race with a significantly lower mortality risk among patients aged younger than 65 years (HR = 0.79; 95% CI, 0.72-0.87), even after adjustment for age, gender, rurality, income, stage, transplant and type of therapy used at induction. The analysis showed no such association among patients aged 65 years and older (HR = 0.99; 95% CI, 0.92-1.07).
“These results suggest that in the VA system, with lack of significant racial difference in utilization of novel therapies or stem cell transplant in multiple myeloma, OS may be superior in African American patients, particularly in the younger population,” the researchers wrote. “Taken with previous research in other health care systems that does demonstrate disparities, our study suggests disparity to be primarily due to socioeconomic factors. Furthermore, the improved outcome in African American [patients with] multiple myeloma also raises an important question about possible differences in disease biology. This is relevant as incidence of multiple myeloma is twofold higher in both men and women, in African American compared to Caucasian patients.” – by Jennifer Byrne
Disclosure s : Fillmore reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.