Multiple Myeloma Outcomes Differ Based on Socioeconomic Factors

Despite the gains made in improving treatment for and care of patients with multiple myeloma (MM), disparities persist based on race and socioeconomic status. In a population-based analysis, Sikander Ailawadhi, MD, of the Division of Hematology/Oncology at the Mayo Clinic in Jacksonville, Florida, and co-authors assessed these discrepancies and observed inferior survival for women, increased costs of care for minorities, and a decrease in mortality for those with higher incomes. The findings were published in Cancer.

Using the National Cancer Institute’s Surveillance, Epidemiology, and End Results Program database, the researchers assessed linked Medicare claims to identify 35,842 cases of primary MM reported between 1991 and 2010. Patients with full Medicare coverage (defined as 12 months of coverage each year) beginning one year prior to diagnosis through the end of 2012 were included. Patients who died within 30 days of an MM diagnosis were excluded from the analysis of complications after diagnosis.

Patients identified as:

  • non-Hispanic white (white; 72%)
  • non-Hispanic black (African-American; 16.2%)
  • Hispanic (7.3%)
  • non-Hispanic Asian/Pacific Islander (Asian; 4.1%)
  • Native American (including “other;” 0.3%)

The researchers collected data on age and year of diagnosis, race, sex, disease complications, and date and cause of death. They also assessed myeloma-defining events (MDEs) of interest: hypercalcemia, renal dysfunction, anemia, bone fracture, and dialysis.

The drug use analysis was limited to 2003 and later because bortezomib – the first proteasome inhibitor for MM – received U.S. Food and Drug Administration approval that year.

During the studied time period, more than half of patients (55%) died because of MM.

The median age at diagnosis was 76 years (range = 18-104 years), and the median follow-up was 1.8 years (range not reported). Women were significantly older at diagnosis, compared with men (median = 77 vs. 75 years; ranges not provided; p<0.001).

The most common MDE before or after MM diagnosis was anemia (17.9% and 25.7%, respectively). The incidence of MDEs increased over time (p<0.001), particularly for hypercalcemia (increased from <0.2% in 1991 to 13.2% in 2006-2010) and bone fractures (increased from 6.6% to 19.2%, respectively).

There were significant differences in all complications at and following diagnosis according to patients’ race (p<0.02), with a high incidence among African-Americans for all MDEs except bone fractures, which were highest among whites. These results suggest “that better MM therapeutics and supportive care lead to less organ damage and possibly more use of dialysis because of longer survival and a willingness to extend supportive care to more patients,” the authors wrote.

Cost of care increased significantly by year of diagnosis, despite adjustment for inflation. Drug claims during the first six months after diagnosis increased sharply, from a median of $230 between 1991 and 1995 to $3,630 between 2006 and 2010 (ranges not reported; p<0.001), and total claims increased from $5,110 to $27,800, respectively (p<0.001).

“There were significant differences in the cost of care by patient race,” the researchers noted.

During the first six months after an MM diagnosis, median drug claims were highest among African-Americans ($1,300) and lowest among Asians ($630; ranges not reported; p=0.009) but increased most steadily among Hispanics (p<0.001).

Drug claims any time after an MM diagnosis were highest among Hispanics ($5,400), followed by Asians ($4,700), African-Americans ($3,900), and whites ($3,300; p<0.001). African-American patients also had the highest number of total claims (p<0.001). “These differences are not clearly explained by disease presentation or complications, because the patterns are not similar to our analysis of MDEs in these patients,” the researchers noted.

In the entire population, overall survival (OS) was 21 percent at five years, 6 percent at 10 years, and 2 percent at 15 years.

People with higher median incomes (>$61,600 vs. ≤$34,700) experienced better OS (hazard ratio [HR] = 0.92; 95% CI 0.87-0.98; p<0.01).

Compared with whites, African-Americans (HR=0.86) and Asians (HR=0.88) had superior OS (p<0.001). Significant differences in OS were observed during various time points, but not during the most recent years (2006-2010), which made the linear trend of OS for all races non-significant over the total study duration (p=0.182).

The following factors were associated with inferior median OS:

  • increased age (HR=1.17; p<0.001)
  • female sex (HR=0.96; p=0.006)
  • earlier year of diagnosis (HR for 2006-2010 = 0.51 [reference category = 1991-1995]; p<0.001)

Of the MDEs, hypercalcemia (HR=1.61; p<0.001), renal dysfunction (HR=1.19; p<0.001), and bone fractures (HR=1.34; p<0.001) were associated with inferior survival.

Almost one-third of patients (32.4%) had a Medicare claim related to anti-MM therapies or hematopoietic cell transplantation (HCT). Overall treatment increased significantly from 29.6 percent in 2003 and 2004 to 63.1 percent in 2009 and 2010 (p<0.001), likely related to the “dramatic” increase in the use of immunomodulatory drugs (IMiDs) and steroids between 2003 to 2004 and 2009 to 2010 (9.5% vs. 29.4% for IMiDs [p<0.001] and 21.5% vs. 499.6% for steroids [p<0.001]).

HCT use increased over time, reaching 14.2 percent in 2009 to 2010. “This increase in HCT use in the Medicare population is likely because of improved supportive care measures as well as earlier treatment for MM leading to the prevention of organ dysfunction and, hence, eligibility for HCT despite patient age in several cases,” the researchers explained. They also observed a “sharp increase” in lenalidomide use, which was considered an expected trend.

“A better understanding and accounting for these factors will ensure that all patients, irrespective of sociodemographic factors, receive benefit from novel therapeutics, health-care access, and health-care use,” the authors concluded.

The study is limited by its reliance on claims-based data, which may have inaccuracies or missing information.

Dr. Ailawadhi reports financial support from Pharmacyclics, Takeda, Amgen, and Novartis.


Reference

Ailawadhi S, Frank RD, Sharma M, et al. Trends in multiple myeloma presentation, management, cost of care, and outcomes in the Medicare population: a comprehensive look at racial disparities. Cancer. 2018 January 23. [Epub ahead of print]

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